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CN120425192B - A rare earth-doped copper-nickel temperature-controlled alloy and its preparation method and application - Google Patents

A rare earth-doped copper-nickel temperature-controlled alloy and its preparation method and application

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CN120425192B
CN120425192B CN202510941952.1A CN202510941952A CN120425192B CN 120425192 B CN120425192 B CN 120425192B CN 202510941952 A CN202510941952 A CN 202510941952A CN 120425192 B CN120425192 B CN 120425192B
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alloy
rare earth
nickel
atmosphere
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CN120425192A (en
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李亚军
刘宜强
邬善江
袁海翔
温奇辉
余音宏
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JIANGSU TUNGSTEN & RARE-EARTH PRODUCT QUALITY SUPERVISION TESTING CENTER
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JIANGSU TUNGSTEN & RARE-EARTH PRODUCT QUALITY SUPERVISION TESTING CENTER
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Abstract

The invention belongs to the technical field of alloys, and particularly relates to a rare earth-doped copper-nickel temperature correction alloy, a preparation method and application thereof, wherein the rare earth-doped copper-nickel temperature correction alloy comprises, by mass, 0-99.995% of Ni, 0.005-1.5% of RE, the balance of Cu and unavoidable impurity elements, and the melting point range of the rare earth-doped copper-nickel temperature correction alloy is 1084.6-1455 ℃. And placing a plurality of rare earth-doped copper-nickel temperature correcting alloys in a container to form an alloy temperature correcting device. The alloy temperature correcting device is placed at a position needing temperature correction and measurement, the state of the alloy temperature correcting device is checked afterwards, and the actual temperature of the position where the alloy temperature correcting device is located is judged according to whether the shape of the alloy temperature correcting device changes. The method has the characteristics of rapid detection, convenient and flexible operation, in-situ operation and no need of connection, the melting point of the temperature correcting alloy is not easily influenced by a small amount of oxygen in the atmosphere, is not influenced by various particle radiation and electromagnetic interference and pressure change, is suitable for temperature correction and measurement of various industrial kilns, and ensures the accuracy of temperature measurement in scientific research and production processes.

Description

Rare earth-doped copper-nickel temperature correction alloy and preparation method and application thereof
Technical Field
The invention belongs to the technical field of alloys, and particularly relates to a rare earth-doped copper-nickel temperature correction alloy, a preparation method and application thereof.
Background
The temperature is a physical quantity representing the degree of cold and heat of an object, and reflects the intensity of thermal movement of molecules inside the object in a microscopic manner. Temperature measurement is widely used, for example, to measure the temperature of various gases, liquids, and solids. In equipment such as industrial furnaces and kilns, such as magnetic material sintering furnaces, hard alloy sintering furnaces, ceramic material sintering furnaces and the like, the temperature measurement and control are very critical, and the technology success, the product quality qualification, the equipment energy consumption standard and the like are directly related.
The temperature measurement and control of various industrial furnaces are generally realized by using thermocouples, thermal resistors, optical pyrometers and the like, and the most widely used industrial temperature measurement and control system mainly comprises thermocouples, compensation wires, meters and the like. There are many factors that affect the accuracy of these systems, such as the thermocouple, the compensating wire and the meter have errors, especially after the thermocouple is used for a period of time, the thermocouple wire is irresistible and unavoidable in degradation due to high temperature volatilization, oxidation, external corrosion and pollution, grain structure change and other reasons, so that the thermoelectric characteristics of the thermocouple gradually change, and thus the temperature measuring and controlling system has larger errors. Thermocouples, meters and the like are also susceptible to interference by external factors such as neutron radiation, electromagnetism and the like, and influence the temperature measurement accuracy.
Pure metals (single element metals) and some alloys have defined melting points, a series of pure metals or alloys with different melting points are placed in a ceramic or glass container, the container is placed in an industrial furnace, if the ambient temperature of the container exceeds the melting point of some pure metals or alloys, the container is melted, the shape of the container becomes liquid, the shape change occurs within a few seconds, then the container is cooled to room temperature, and the shape of the container still can be kept after melting, and if the ambient temperature is lower than the melting point of some pure metals or alloys, the pure metals or alloys are not melted, and the shape of the container is not changed obviously. The real temperature of the kiln where the containers are located can be conveniently obtained by directly observing the transparent containers at high temperature or checking the shape change of the pure metals or alloys after cooling to normal temperature and judging whether the pure metals or alloys are melted. For example, the prior art finds that the temperature in the dry quenching furnace is up to more than 1000 ℃, the working temperature of the bracket bricks is difficult to accurately measure by a common temperature measuring method, and the bracket bricks at different positions cannot be properly selected, so that the internal stress is accumulated in the bracket bricks, and finally cracks are generated on the surfaces of the bricks. In order to solve the problems, a temperature measuring device and a temperature measuring method for accurately measuring a three-dimensional temperature field of a bracket brick are proposed, wherein a plurality of metal or alloy blocks with melting points in equal difference rows are placed in a refractory box divided into a plurality of small grids, the refractory box is placed at the position of the bracket brick, the actual temperature of the position of the refractory box can be judged according to whether the metal or alloy is melted or not, namely, the actual temperature is between the melting point of a metal block with the highest melting point and a metal block with the lowest melting point in a metal block without melting, such as a metal block with the melting point of 1045 ℃ in one refractory box, but the metal block with the melting point of 1048 ℃ is not melted, and the temperature of the point can be accurately known to be 1045-1048 ℃ according to whether the metal or the alloy is melted or not. The above technical solution does not mention the specific atmosphere of the environment in which the bracket brick is located and the influence of oxygen possibly present in the atmosphere on the melting point of the temperature-sensing metal.
The reactor core is in a high-emissivity environment or in an extreme environment such as neutron irradiation experiments, and the temperature of the reactor core needs to be monitored by a relatively accurate method. Under severe neutron irradiation conditions, conventional temperature measurement methods such as thermocouples and the like cannot be used normally to accurately measure or evaluate the temperature of the environment. Because the melting point of the metal is not easily affected by high-energy radiation and large-dose neutron radiation, a series of temperature measuring alloys and application methods, such as silver-lithium alloy, antimony-containing alloy, lead-bismuth alloy and the like, are developed at present, and according to the characteristics of shape change, flow and the like of the alloy after melting, the environmental temperature measurement at 180-1200 ℃ under the condition of strong neutron radiation can be realized, so that the problem is solved well. The metal is called as temperature-measuring alloy, usually contains active elements, is easy to react with oxygen in the environment, reduces the temperature-measuring precision of the metal, and even leads the temperature-measuring alloy to be completely ineffective. In order to avoid the problems of oxidization and the like, the temperature measuring alloy is required to be sealed by a quartz tube or an anti-corrosion metal tube, inert gas is filled or vacuumized to manufacture the temperature measuring device, and after the temperature measuring device is used, whether the alloy is melted or not is judged by measuring the gravity center change of the temperature measuring device or checking the state, dripping condition and the like of the temperature measuring alloy by a splitting device, so that a temperature measuring value is obtained. The proposal of completely isolating the influence of oxygen on the alloy melting point in the external environment atmosphere by completely sealing the temperature measuring metal by using the quartz tube or the metal tube has limitation because the kiln is collapsed or burst due to overlarge pressure difference between the inside and the outside of the temperature measuring device when the high-temperature high-pressure and high-temperature high-vacuum atmosphere is changed, and the temperature measuring device is in failure risk.
The industrial furnace generally uses a temperature measuring and controlling system to realize an automatic heating function, but as the service time of temperature measuring and controlling system components such as a temperature sensor is increased, the system error is gradually increased, so that the temperature displayed and controlled by the system is gradually deviated from the actual temperature, and if the temperature calibration and compensation are not performed in time, the actual temperatures of various industrial furnaces are gradually deviated from target values (the temperatures required by the process), so that the quality and performance of products are fluctuated. Therefore, in order to ensure the accuracy and reliability of the measurement accuracy and temperature measurement of the industrial furnace temperature measuring and controlling system, the furnace in use needs to be calibrated at regular or irregular intervals, the probe of the existing temperature measuring system is far away from the position of the furnace where the processed material is placed, the real temperature of the processed material cannot be usually detected, and a method for detecting the real temperature of the material is needed to be developed.
In order to comprehensively and accurately monitor and calibrate the kiln temperature and ensure uniformity of an internal temperature field, and ensure stable product quality, the aerospace industry and the automobile industry widely adopt on-site high-temperature measurement calibration procedures to calibrate the industrial kiln temperature periodically, namely AMS2750 and CQI-9 respectively. Both of these procedures specify the requirements for instrumentation, hot working equipment, thermocouples, temperature uniformity measurements, and system accuracy testing. According to the regulation requirements, a square long body or a cylinder-shaped bracket is required to be erected in the furnace, a plurality of calibration thermocouples are installed on the bracket, and are connected with a calibration instrument outside the furnace by using wires to perform on-site calibration on the temperature and uniformity of the furnace. The calibration method can calibrate the furnace temperature and the temperature uniformity at the same time, has the defects that the calibration procedure is relatively complex, the professional training is needed for operators, the normal production of the furnace kiln is needed to be interrupted, the furnace kiln is emptied, the bracket and the temperature calibration equipment are installed, and the like, a large amount of energy sources are wasted during the calibration, the workload is large, the calibration cost is high, the calibration thermocouple and the connecting wire are directly installed in the furnace, and the heat insulation of the connecting wire is difficult under the high-temperature environment, so that the method is difficult to perform the temperature calibration operation under the environment of more than 1200 ℃.
In industrial production, many processes such as heat treatment, sintering and the like are carried out in kilns with the temperature of 1300-1450 ℃, such as stainless steel injection molding products, hard alloy sintering and the like, and the working temperature of the kilns exceeds 1200 ℃, so that how to simply and accurately calibrate the temperature of the kilns and how to accurately measure the real temperature of treatment materials and workpieces in situ becomes a concern of technicians and a problem to be solved urgently.
Hard alloy is a composite material with excellent properties such as high strength, high hardness, high wear resistance and the like, which is prepared by bonding hard refractory metal compounds with soft transition metals through a powder metallurgy method, and is widely applied to the fields of cutting processing, tunnel excavation, mining and the like and is known as a tooth in the modern industry. Cemented carbides are usually sintered at 1380-1460 ℃, a lower vacuum or furnace pressure reaching 100bar argon atmosphere, the sintering process and temperature are one of the key factors influencing the performance of cemented carbides, and after sintering, the internally porous powder compact is made into a material with hard metallurgical bonding and better fracture toughness. The correct sintering temperature can enable the hard alloy powder to be quickly solidified and formed, is favorable for improving the density and strength of the hard alloy, and obtains a product with excellent comprehensive performance. Too low sintering temperature can lead to low density and poor strength of the hard alloy, too high sintering temperature can easily lead to uneven grain growth, and the problems of sintering cracks, even sintering failure and the like can also occur when the sintering temperature is severe. The temperature of each part of the effective space of the hard alloy sintering furnace is difficult to be uniform due to factors such as equipment structure, the temperature distribution in the furnace is gradually changed due to ageing of a heating body, a heat insulation material and the like in the using process, and the temperature displayed and controlled by the system is gradually deviated from the actual temperature due to the gradual increase of the using time of a temperature sensor, a temperature control instrument and the like and the gradual increase of errors. Therefore, the real temperature of the hard alloy sintering furnace and the uniformity of the detected temperature field are confirmed to become main indexes of process quality control and performance evaluation of hard alloy sintering furnace equipment in the hard alloy production process, so as to ensure that the quality and performance of the final product meet the requirements.
In the prior art, a special hard alloy pressed compact or a secondary sintered hard alloy block is usually adopted to calibrate the temperature of a sintering furnace, and the principle is that the actual sintering temperature is obtained by utilizing the fact that the coercivity of a hard alloy material and the sintering temperature have a certain corresponding relation and back-pushing. The method for determining the temperature difference by using the property difference of the material lacks of unified standard, particularly the hard alloy temperature correction block dewaxed simultaneously along with the whole furnace product can be influenced by the temperature and atmosphere non-uniformity during the dewaxing of the whole furnace, so that the magnetic saturation difference is caused, the magnetic saturation and the coercive force have obvious negative correlation, the coercive force accuracy can be influenced, and the temperature correction accuracy is further influenced. Up to now, there is no better method for accurately calibrating the temperature of a cemented carbide sintering furnace in situ.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a rare earth doped copper-nickel temperature correction alloy, and a preparation method and application thereof.
N pure metals and alloys with non-spherical shapes and gradually increased melting points (such as adjacent alloys with melting point difference of about 2-20 ℃) are grouped, the melting points are covered in a certain range and are marked as { T a(1)、Ta(2)、…、Ta(n) }, wherein T a(1) ℃ represents the melting point of the alloy a (1) with the lowest melting point in the group of metals, T a(n) ℃ represents the melting point of the alloy a (n) with the highest melting point in the group, and T a(1)＜Ta(2)＜Ta(3)＜…＜Ta(n-2)＜Ta(n-1)＜Ta(n). The alloys are placed in a small container and combined to form a device, the device is marked as { T a(1)~Ta(n) }, the device is placed in a furnace with the requirement of detecting the real temperature, when the real temperature of the furnace is within the range covered by the melting points of the alloys, the metal with the melting point lower than the real furnace temperature in the small container is melted to generate obvious shape change, such as the alloy with the number of 1,2 and the number of the first and the second, is in a similar sphere shape after being melted, the metal with the melting point higher than the real furnace temperature is not melted, such as the alloy with the number of the first and the second, has no obvious shape change, or has a non-sphere shape, so that the real furnace temperature can be determined according to whether the shape of the alloy is obviously changed after being used, namely the real furnace temperature is between the [ T a(n-3),Ta(n-2) ]. C, the range is dependent on the melting point temperature of the adjacent alloys, and can be controlled to be 2-5 ℃ better, thus accurate temperature measurement is realized. The alloy temperature measuring device, the materials to be processed and the workpieces are placed together, normal production of a kiln is not affected during temperature measurement, real temperature measurement of the materials and the workpieces is realized in the process or after the process is finished, the temperature measuring method is called in-situ temperature measurement, and the alloy temperature measuring device can conveniently realize in-situ temperature measurement. The above method gives a true furnace temperature, noted T z ℃, in the present invention T z=(Ta(n-3)+Ta(n-2))/2. The alloy temperature measuring device can be assembled according to the descending order of the melting points of the alloy, and the final effect is not affected.
If the furnace is provided with a temperature measuring and controlling system, the highest process temperature is set as T s ℃, which is the process target temperature, and in the operation process, the corresponding temperature measuring system can measure and obtain the highest measured temperature, which is marked as T c ℃, and the two values are very close under normal conditions, so that T s=Tc can be considered. The actual temperature values T z and T s、Tc of the kiln obtained by using the alloy temperature measuring device have a difference value, T z-Ts=Tz-Tc =DeltaT, deltaT is the temperature required to be compensated by the system, so that the temperature calibration of the kiln is realized, and the device capable of realizing the function is called an alloy temperature calibrating device, and the alloy is called a temperature calibrating alloy. The method of calibrating kiln temperature using the alloy temperature calibrating device is called an alloy temperature calibrating method. The alloy temperature correction device and the materials to be treated are placed together, the normal production of a kiln is not affected during temperature correction, the actual temperature correction of the materials is realized in the process or after the process is finished, the temperature correction method is called in-situ temperature correction, and the alloy temperature correction method can realize in-situ temperature correction.
The temperature calibration alloy can realize the measurement of the ambient temperature, is mainly used for an alloy temperature calibration device and realizes the function of in-situ temperature calibration, and when the temperature calibration alloy is used for temperature calibration, the temperature measurement is also carried out at the same time, so the two concepts of 'temperature measurement alloy' and 'temperature calibration alloy' are considered as synonymous in the application and can be replaced. Likewise, in the present application, "temperature calibration" and "temperature measurement" may be exchanged synonymously, and "alloy temperature measurement device" and "alloy temperature calibration device" may be exchanged synonymously.
For copper-nickel alloys, the copper (Cu) is 100-0% by mass and the nickel (Ni) is 0-100% by mass, the alloy having a composition in this range has a specific melting point, the alloy melting point increasing gradually with increasing nickel content, from 1084.6 ℃ to about 1455 ℃. Copper-nickel alloy is infinite solid solution alloy at any temperature, so the copper-nickel alloy has potential as a temperature correction alloy for accurately correcting the temperature of an industrial furnace with the working temperature of 1084.6-1455 ℃, such as accurately correcting the temperature of a hard alloy sintering furnace in situ.
The inventor finds that even if the temperature correcting device is strictly fixed and placed at the same position of the sintering furnace every time when the temperature correcting alloy is used for accurately correcting the temperature of the sintering furnace, under the condition that the sintering process settings are identical, namely T s、Tc is identical, the measured real temperature T z ℃ is greatly different when the temperature is corrected for a plurality of batches in a plurality of continuous days. Preliminary analysis found that the fluctuation of the T z value was related to the atmosphere pressure during the operation of the sintering furnace. Through careful examination, it was found that many factors affect the furnace atmosphere pressure in the sintering furnace, and how much of each batch of load material, and even different workers operating the furnace door seals, affect the furnace atmosphere pressure. Further analysis shows that the pressure value of the atmosphere in the furnace does not directly influence the melting point of the temperature correcting alloy, but trace oxygen in the atmosphere influences the melting point of the temperature correcting alloy, so that the T z value fluctuates, the oxygen partial pressure value in the atmosphere is generally directly related to the pressure of the atmosphere, the larger the pressure of the atmosphere is, the larger the oxygen partial pressure is, and at the moment, the melting point of the temperature correcting alloy is greatly changed under the action of oxygen in the atmosphere, so that accurate temperature correction cannot be realized.
Those skilled in the art concerning heat treatment, sintering, etc., generally know that a trace amount of oxygen is always contained in the atmosphere inside an industrial furnace, mainly because 78.08vol% of nitrogen, 20.95vol% of oxygen, 0.93 vol% of argon, 0.038vol% of carbon dioxide, and 0.002vol% of other gases are contained in the air. In the furnace charging and discharging processes, air enters a hearth, the air cannot be completely removed by inflation cleaning or vacuumizing, a certain amount of air remains, meanwhile, workpieces, refractory materials, heat insulation materials and the like can absorb oxygen in the air, the absorbed oxygen can be released in the heating process, and industrial nitrogen, argon, hydrogen and other gases can remain and be mixed with a small amount of air in the production, storage and transportation processes, so that trace oxygen enters the industrial furnace atmosphere. The sealing performance of the industrial kiln is gradually reduced along with the extension of the service time, and the abrasion of a vacuum system is gradually increased, so that the oxygen in the atmosphere inside the kiln is gradually increased.
Therefore, when the atmosphere in the industrial furnace is in vacuum, inert, reducing and other atmospheres, the atmosphere contains a certain amount of oxygen, namely the oxygen is ubiquitous, and the difference is only that the oxygen content in the atmosphere is more or less, namely the oxygen partial pressure is high. The inventors found that during the use process of the temperature correcting alloy, the alloy tends to absorb impurities such as oxygen in the furnace kiln atmosphere, and if the impurities enter the alloy crystal lattice, the impurities become crystal lattice interstitial atoms and substitution atoms (which can be considered as absorbing and dissolving oxygen in the crystal lattice), the melting point of the alloy can be changed, for example, pure copper absorbs 0.008 percent of oxygen by mass and the melting point is reduced from 1084.6 ℃ to 1066 ℃, pure nickel absorbs 0.05 percent of oxygen by mass, and a liquid phase starts to appear at 1440 ℃ (refer to binary alloy phase diagram and mesophase crystal structure, published by the university of south China, 2009, ISBN: 9787811058314), so that the existence of oxygen in the atmosphere can seriously influence the temperature correcting precision of the alloy.
For the alloy with specific components, how much oxygen can be absorbed and dissolved in the alloy lattice depends on the temperature of the environment where the alloy is located, the partial pressure of oxygen, the surface state of the alloy, the type and content of alloy elements, the reaction time and other factors to act together, and the alloy is a very complex process, and is not deeply explored in the invention. For the results and mechanisms of interaction with oxygen in the atmosphere for a particular alloy system, reference can be made to published literature.
Through a large number of researches and temperature calibration practices, the inventor finds that the accurate calibration of the kiln temperature by using the alloy temperature calibration method needs to solve the key problems of (1) influencing the melting point of the temperature calibration alloy by trace oxygen in the furnace atmosphere, (2) judging whether the temperature calibration alloy is melted or not by adopting a mode, and (3) influencing the temperature measuring device by the change of the atmosphere pressure in the industrial kiln. Only the alloy temperature correction method can ensure the temperature correction precision and is widely applied to the field of industrial furnace temperature correction. The three problems are mutually influenced, and when an alloy temperature correcting scheme is designed, the three problems are considered as a whole to be solved, so that the alloy temperature correcting technical scheme is overall better and has wide applicability.
In order to overcome the influence of oxygen in atmosphere on the melting point of the temperature correcting alloy, the alloy is usually sealed in a vacuum or a container filled with protective gas in the prior art, so that the temperature correcting alloy is isolated from the atmosphere in a furnace kiln, the temperature measuring device is complicated, large in volume and high in cost due to the treatment, the temperature measuring device is only suitable for a certain furnace kiln with small change of the atmosphere pressure in the furnace kiln, and if the high-temperature furnace kiln has large change of the atmosphere pressure in the process, the sealing temperature measuring device is invalid due to collapse, cracking and the like caused by large change of the pressure range in the high temperature. If the glass is made into a container to be loaded with the temperature correction alloy, the container is placed in a kiln after being vacuumized and sealed, and when the temperature of the kiln is over 1000 ℃ and the pressure in the kiln exceeds 10 atmospheres, the sealed glass container may collapse, so that the temperature correction is invalid.
If the temperature measuring device is not sealed, oxygen in the external atmosphere of the device can fully contact with the temperature correcting alloy, more oxygen can enter into the crystal lattice of the temperature correcting alloy matrix and can greatly influence the melting point of the temperature correcting alloy, so that the temperature correcting and measuring precision is low, and a person skilled in the art does not fully realize that trace oxygen in the internal atmosphere of the kiln can greatly influence the melting point of the temperature correcting alloy and influence the temperature correcting precision.
The inventor finds that other elements are not doped in the copper-nickel temperature correcting alloy through a large number of researches, when trace oxygen in the atmosphere is in contact with the surface of the temperature correcting alloy, the activities of copper and nickel elements in a copper-nickel alloy matrix are insufficient at high temperature, oxygen cannot be fixed to generate oxide second-phase precipitates, trace oxygen can enter crystal lattices of the copper-nickel alloy matrix to become crystal lattice interstitial atoms and replacement atoms, so that the melting point of the alloy is reduced, for example, the pure copper absorbs oxygen with the atomic ratio of 0.008%, and the melting point is reduced from 1084.6 ℃ to 1066 ℃, so that the temperature correcting precision is reduced. And rare earth elements (RE) with very active properties are added into the copper-nickel alloy, so that adverse effects of oxygen in the atmosphere on the melting point of the temperature correcting alloy during temperature correction can be effectively reduced and controlled.
The enthalpy of formation Δh f of the metal oxide is a physical quantity reflecting the stability of the oxide, and the lower the value, the more stable the metal oxide is, and the more active the metal element is, the more easily the metal element reacts with oxygen. In the traditional (structural) steel, oxygen in molten steel is usually added during smelting, such as Mn, si, al and the like, the oxygen content of the silicon-added deoxidized and killed steel can reach below 30 multiplied by 10 -6, the oxygen content of the aluminum-added deoxidized and killed steel can reach below 20 multiplied by 10 -6, and more active rare earth elements such as cerium (Ce), lanthanum (La), yttrium (Y) and the like are required to be added for further deep deoxidization, wherein the deoxidization performance of the rare earth elements is far higher than that of aluminum.
The research of the invention finds that if a small amount of rare earth metal elements are doped in the copper-nickel temperature correcting alloy, rare earth can form intermetallic compounds with copper and nickel, and the intermetallic compounds mainly precipitate at grain boundaries to form dispersed and distributed fine second phases. When trace oxygen in the atmosphere contacts with the temperature correcting alloy to enter the alloy matrix, the rare earth metal element is more active than nickel and copper element, RE mOn is more stable than NiO and Cu 2 O in thermodynamics (see table 1), the formation enthalpy of Y 2O3、NiO、Cu2 O is-627 kJ/mol, -240 kJ/mol and-171 kJ/mol respectively, and the rare earth element in the copper-nickel alloy preferentially reacts with oxygen in a copper-nickel lattice at high temperature. Because the atomic radius of the rare earth element is relatively large (144-204 pm), the solid solubility and the diffusion rate of the rare earth element in the copper-nickel matrix are very low, meanwhile, the atomic radius of oxygen is relatively small (66 pm), oxygen is easier to diffuse into the alloy matrix, the rare earth at the grain boundary can capture oxygen diffused into the alloy from atmosphere, and a fine rare earth oxide particle precipitated phase is generated at the grain boundary in the copper-nickel alloy matrix, so that the purification effect is achieved. The principle is similar to the deoxidizing principle for producing calm steel, and the difference is that rare earth is added into the temperature correcting alloy to control the free oxygen amount in solid crystal lattice before the temperature correcting alloy is not melted in use, so that the melting point of the temperature correcting alloy is not affected by oxygen in atmosphere before the temperature correcting alloy is melted.
Oxygen reacts with rare earth elements, the content of copper and nickel elements in a copper-nickel matrix is not reduced, the melting point of the copper-nickel matrix is not influenced, rare earth is very active, free oxygen in an alloy matrix can be reduced to below 5ppm (the low oxygen content can be considered that oxygen does not influence the melting point of the alloy), the influence of oxygen in a crystal lattice on Jin Rongdian is eliminated, the melting point of a temperature correcting alloy is stabilized, fine rare earth oxides are mainly dispersed and distributed in crystal boundaries, a compact firm surface film is not formed, the melting point of the rare earth oxides is above 2200 ℃, the rare earth oxides are stable at high temperature, the rare earth oxides are not dissolved or decomposed in the alloy matrix, the melting point of the matrix is not changed, the surface tension and the wettability with a container during alloy melting are not influenced, the shape change of the alloy after melting is not influenced, and the accuracy of temperature correction can be ensured.
Based on the mechanism, rare earth elements are added into the copper-nickel alloy, so that the influence of oxygen in the atmosphere on the melting point of the temperature correcting alloy is well solved.
TABLE 1 enthalpy of formation of solid oxides of metallic elements such as RE, cu, ni, ΔH f (0.5 mol oxygen consumption)
Table 1 data is cited in the literature ：DTA and Heat-flux DSC Measurements of Alloy Melting and Freezing: NIST Recommended Practice Guide, Special Publication 960-15. National Institute of Standards and Technology, Washington, DC, USA 2006.
According to the invention, 2% of rare earth is doped into the alloy, and the alloy can be strongly adhered to the container wall no matter whether the alloy is melted or not when the alloy is used for temperature correction, because the container for containing the rare earth-doped copper-nickel temperature correction alloy is made of oxide, such as zirconia, alumina and the like, RE is very active, RE with higher concentration in the temperature correction alloy can react with the container at high temperature to react violently, part of oxygen in the container material is extracted to form complex oxide, so that the container has color change, strength is reduced, a large amount of container material elements enter the temperature correction alloy to change the melting point of the temperature correction alloy, the temperature correction alloy is strongly adhered to the container and the like. Although when temperature correction and low temperature measurement precision are required, the temperature correction and temperature measurement can be realized by using the temperature correction alloy with the rare earth content higher than 2%, and the rare earth mass percent content in the preferred temperature correction alloy is not more than 2%.
Rare earth metal elements hardly form gaps or substitution solid solutions with a copper-nickel matrix, and the solid solubility is small, but rare earth and copper and nickel can form a low-melting-point eutectic alloy, for example, the eutectic temperature of 18 percent by mass of rare earth cerium (Ce) and copper is 876 ℃, and the eutectic temperature of 19 percent by mass of rare earth Ce and nickel is 1210 ℃. Therefore, when the rare earth is added in a larger amount, the melting point of the copper-nickel matrix can be changed greatly, so that the temperature correction precision is reduced. The research of the invention shows that the addition of rare earth metal elements is controlled within 1.5 percent (mass percent), and the ideal temperature correction precision can be obtained.
In addition, the RE content in the alloy is too low, for example, the RE content is lower than 0.005 percent by mass, and in the use process, after the RE in the temperature correcting alloy is quickly consumed by oxygen, the RE cannot continuously react with oxygen entering the crystal lattice of the copper-nickel alloy matrix in the atmosphere, and the RE is changed into crystal lattice interstitial atoms and replacement atoms, so that the melting point of the alloy is reduced, and the temperature correcting precision is reduced.
The inventor finds that the better rare earth doped mass percent in the temperature-correcting alloy is 0.005-1.5%, the suboptimal rare earth doped mass percent is 0.08-1.00%, the better rare earth doped mass percent is 0.09-0.60% and the optimal rare earth doped mass percent is 0.10-0.35 through a great deal of researches and alloy temperature-correcting practice summary.
During the development of the invention, the initial shape of the metal or alloy sample before temperature calibration can be very varied. The shape of the sample is mainly determined by the metal or alloy material and the sample manufacturing method from the viewpoint of the processing technology, but no matter how different the initial shape is, the shape after melting-solidification is not necessarily related to the initial shape of the sample. The key factors determining the shape of the molten-solidified temperature correcting alloy sample are the material of the container, the shape and size of the container and the dosage of the temperature correcting alloy sample.
By selecting proper container materials, designing the shape and the size of the container and controlling the dosage of the alloy sample, the final shape of the temperature correcting alloy sample after the temperature correcting alloy sample is subjected to the melting-solidification process can be controlled, various shapes from simple to complex can be realized, and whether the alloy is melted or not can be judged according to the shape after temperature correction, so that temperature information needing to be corrected is obtained. Among these possible solutions, the solution is designed to control the final shape of the master alloy sample after melting-solidification to be spherical or spheroidic, and the inventors consider the solution to be a preferable solution, and may be the best solution, in which case the master alloy sample is used in a small amount, the sample eventually becomes spherical or spheroidic after melting, the technicians can conveniently determine whether the alloy is melted, the container is hardly stuck after melting, and the container can be reused after simple cleaning.
According to the principle of the invention, through a great deal of experiments and optimization design, the inventor invents a better alloy temperature correcting device. The alloy temperature correcting device consists of a small container, a small container cover, a large container cover and temperature correcting alloy.
The material selection of the small container is based on that the reaction between the temperature correcting alloy and the small container does not occur at high temperature or the reaction is very slight and does not influence the inherent melting point of the temperature correcting alloy and the morphological change after melting, so that the preferred container material is high-temperature resistant oxide.
Further, the shape of the small container can be various shapes which are easy to process and obtain, and the preferred shape is a cylindrical crucible shape with a cover. The shape and size of the large container should ensure that a plurality of small containers are stacked in the large container without toppling, and the large container needs to be provided with a large container cover. The material of the large container is high-temperature resistant oxide ceramic or metal.
The shape of the temperature correcting alloy can be various non-spherical shapes which are easy to process and crush, further, the preferable shape is a short wire shape or a flake shape with any dimension size smaller than 6mm, so that the temperature correcting alloy is conveniently distinguished from the alloy which is melted and becomes spherical under the action of surface tension, an operator can judge the temperature of a test position without special tools and special knowledge, and accurate calibration of the temperature is realized.
The industrial kiln may need to be subjected to complex and changeable atmospheres such as low temperature-high temperature-low temperature, vacuum-low pressure-normal pressure-high pressure and the like in the whole process of processing workpieces and products. By using a sealed vacuum pumping or an inflatable protection seal for the temperature correcting alloy, the temperature correcting alloy can be protected from the influence of trace oxygen in the external environment atmosphere, but cannot adapt to such complex pressure and temperature environment changes, for example, the temperature measuring device is sealed and vacuumized at low temperature, the temperature measuring device can collapse and crack to fail when the temperature measuring device is in high temperature and high pressure, the temperature measuring device is sealed and inflated at low temperature, and the device can fail when the temperature measuring device is in high temperature and vacuum. The alloy temperature correcting device can exchange atmosphere through the gap under the driving of pressure difference when pressure difference exists between the small container and the large container and between the large container and the external environment atmosphere in the heating, cooling and pressurizing processes, namely, gas can enter and exit the container through the gap between the container and the cover, so that the pressure balance of the atmosphere inside the container and the external atmosphere is realized, the possible damage of the alloy temperature correcting device caused by the pressure change of the atmosphere inside the kiln is avoided, the problems of complexity and narrow adaptability of the temperature correcting device caused by complete sealing are solved, and the alloy temperature correcting device can realize accurate temperature correction and temperature measurement under various pressure conditions from negative pressure to positive pressure of the low oxygen atmosphere and can be widely applied to temperature correction and temperature measurement of industrial kilns.
If in a process, when the oxygen partial pressure is less than or equal to 400Pa, the vacuum absolute pressure is sometimes less than 0.001Pa, and the pressurizing pressure sometimes exceeds 2500bar, because the alloy temperature correcting device adopts the scheme of the invention, accurate temperature correction and temperature measurement can be realized, if a completely sealed scheme is adopted, a proper sealing material is difficult to find, and the alloy temperature correcting device can bear the great change of the external high temperature and pressure at the same time without failure.
In order to ensure the service life of the installed temperature detector of the industrial furnace, and also the factors of convenience in feeding and discharging, ensuring the cleanness of the detector and the like, the position of the temperature detector is usually far away from materials and workpieces processed by the industrial furnace, and the temperature detector is more inconvenient to penetrate into the materials and the workpieces, so that the temperature measured by the temperature detector is usually deviated from the actual temperature of the materials and the workpieces, and the error is larger. The alloy temperature correcting device developed by the invention can be placed together with materials and workpieces to be processed, even placed in the materials and the workpieces, and the actual temperature of the materials and the workpieces measured in situ can be obtained according to the change of the shape of the alloy temperature correcting device after the heating process is finished.
The alloy temperature calibration device and the alloy temperature calibration method are based on the proper use amount of the temperature calibration alloy and the proper container shape matching design, so that the alloy is melted into a sphere under the action of surface tension, and the temperature calibration and temperature measurement functions are realized. If the amount of the master alloy is large and the volume of the capsule is small, the amount of liquid after the master alloy is melted exceeds the amount required to fill the entire capsule bottom, in which case the shape of the master alloy after melting-solidification depends on the shape of the capsule bottom. Under the condition, according to the condition that the bottom of the container is filled after solidification, whether the temperature correcting alloy is molten or not can be judged, and the aims of temperature correction and temperature measurement are achieved.
Based on the principle, the invention has the following beneficial effects:
(1) The copper-nickel temperature correction alloy is doped with a small amount of active rare earth metal elements, so that the problem that the melting point is easily influenced by oxygen in atmosphere is solved, the temperature correction precision is high, and the adaptability is wide.
(2) The temperature correcting alloy has small usage amount, the container is not wetted after the alloy is melted to be spheroidized, and whether the alloy is melted is intuitively judged according to whether the alloy is spheroidized or not without other detection means.
(3) The alloy temperature correction device formed by assembling the temperature correction alloy and the large and small containers with the covers does not need vacuum or filling inert gas for encapsulation, the pressure inside the containers and the pressure inside the kiln can be balanced freely, and the speed of oxygen diffusion in the external environment atmosphere entering the alloy temperature correction device is controlled, so that the alloy temperature correction device is suitable for industrial kiln temperature correction and measurement under various pressure conditions with the oxygen partial pressure less than or equal to 400 Pa.
(4) The alloy temperature correcting device is small, is not interfered by other factors, and can realize in-situ temperature correction and measurement.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic cross-sectional view of an alloy temperature calibration device according to the present invention.
Fig. 2 is an enlarged view of a part of a schematic cross-sectional structure of an alloy temperature calibration device according to the present invention.
Fig. 3 is a schematic cross-sectional structure of an alloy temperature calibration device after use.
FIG. 4 shows the results of energy spectrum analysis of the ECN-03 alloy sample cut in example 1 of the present invention.
FIG. 5 shows the results of energy spectrum analysis of the ECN-05 alloy sample cut in example 1 of the present invention.
FIG. 6 is a SEM of an ECN-05 alloy sample after evaluation of the atmospheric sensitivity of P1415.0-20-40 in example 1 of the present invention.
FIG. 7 shows the analysis result of the surface energy spectrum of the ECN-05 alloy sample after the atmosphere sensitivity evaluation of P1415.0-20-40 in example 1 of the present invention.
FIG. 8 is a SEM of an ECN-03 alloy sample after evaluation of the atmospheric sensitivity of P1415.0-20-40 in example 1 of the present invention.
FIG. 9 is a graph showing the analysis result of the surface energy spectrum of the ECN-03 alloy sample after the atmosphere sensitivity evaluation of P1415.0-20-40 in example 1 of the present invention.
FIG. 10 is a schematic diagram of the arrangement of the rare earth doped copper nickel temperature correcting alloy device in the A-05# cemented carbide sintering furnace in example 4 of the present invention.
FIG. 11 is a graph showing the melting result of the temperature-controlled alloy at the position point 1 in example 4 of the present invention.
In the figure, a 1-small container, a 2-small container cover, a 3-large container, a 4-large container cover, a 5-temperature correcting alloy, a 6-alloy temperature correcting device, a 7-space I, an 8-space II, a 9-alloy temperature correcting device outside, a 10-gap structure I, an 11-gap structure II, a 21-front furnace door, a 22-rear furnace door, a 101-temperature measuring point I, a 102-temperature measuring point II, a 103-temperature measuring point III, a 104-temperature measuring point IV, a 105-temperature measuring point five, a 106-temperature measuring point six, a 107-temperature measuring point seven, a 108-temperature measuring point eight, a 109-temperature measuring point nine, a 1010-temperature measuring point ten and a 1011-temperature measuring point eleven are shown.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description will be made clearly and fully with reference to the technical solutions in the embodiments, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
According to the principle of the invention, through a great deal of experiments and optimization design, the inventor invents a better alloy temperature correcting device, as shown in figure 1. Fig. 1 is a schematic cross-sectional structure of the preferred alloy temperature calibrating device, and the alloy temperature calibrating device 6 consists of a small container 1, a small container cover 2, a large container 3, a large container cover 4 and a temperature calibrating alloy 5. The schematic cross-sectional structure of the alloy temperature correcting device shown in fig. 1 is only an example of the structure of the alloy temperature correcting device provided by the invention, and is only for visually showing the components of the alloy temperature correcting device of the invention, and the actual structure of the alloy temperature correcting device can be optimized according to the principles of the invention.
The material selection of the small container is based on that the reaction between the temperature correcting alloy 5 and the small container 1 does not occur at high temperature or the reaction does not affect the inherent melting point of the temperature correcting alloy or the shape change after melting very slightly, so that the preferred container material is high temperature resistant oxide such as silicon oxide, aluminum oxide, zirconium oxide, yttrium oxide, cerium oxide, lanthanum oxide and the like, and meanwhile, the molten liquid of the temperature correcting alloy 5 and the container should not be fully wetted, namely the contact angle is more than 60 degrees, preferably more than 90 degrees, most preferably more than 110 degrees, so as to ensure that the molten alloy becomes spherical or spheroidic under the action of surface tension.
Further, the shape of the small container 1 can be various shapes which are easy to process and easy to obtain, and the preferred shape is a cylindrical crucible shape with a cover. Further, the size of the small container 1 can be as small as possible under the condition of meeting the use condition, the volume of the small container 1 is preferably 50-250 mu L, and after the temperature correcting alloy 5 is placed, the total volume of the space I7 (the space I7 is the residual space formed by subtracting the volume of the contained temperature correcting alloy from the internal space formed by adding the container cover to the small container) is small, so that the total amount of oxygen in the space I7 is small. Thus, the total gas amount contained in the capsule 1 can be less than 200 mu L, and a local environment which is almost free of oxygen in the atmosphere can be formed inside the capsule 1 after the rare earth in the temperature correcting alloy 5 consumes oxygen in the atmosphere in the temperature correcting process.
The shape and size of the large container 3 should be such that a plurality of small containers 1 are stacked in the large container 3 without toppling over, and the large container 3 needs to be provided with a large container cover 4. Further, the shape of the large container 3 may be various shapes which are easy to process and easy to obtain, and the preferred shape is a cylindrical crucible shape with a cover. Further, the size of the large container 3 is preferably 1-6 mm larger than the outer diameter of the small container 1, so that the space II 8 (the space II 8 is the space left by subtracting the total volume of all the small containers with caps from the inner space formed by adding the container caps to the large container) is relatively small, and the small containers 1 can be conveniently stacked and taken out from the large container 3. The material of the large container 3 should be high temperature resistant oxide ceramic or metal.
The shape of the temperature correcting alloy 5 can be various non-spherical shapes which are easy to process and crush, further, the preferable shape is a short wire shape or a flake shape with any dimension size smaller than 6mm, and the temperature correcting alloy is convenient to distinguish from the alloy which is melted and becomes spherical under the action of surface tension, so that operators can judge the temperature of a test position without special tools and special knowledge, and accurate calibration of the temperature is realized.
Further, the volume of the rare earth doped copper-nickel temperature correcting alloy placed in the small container 1 is 1/20-1/2 of the volume of the small container 1, so that the temperature correcting alloy 5 placed in the small container 1 does not occupy the bottom of the whole small container 1 after being melted, and forms a sphere or spheroid under the action of surface tension after the temperature correcting alloy 5 is melted, and the shape can be maintained in the subsequent process, particularly after being cooled down, and can also maintain the sphere or spheroid.
The addition of active rare earth elements to the temperature-correcting alloy can control the amount of oxygen absorbed from the external atmosphere and dissolved in the crystal lattice of the alloy matrix, so that the melting point of the alloy matrix is not affected by trace oxygen in the atmosphere, but the allowable amount of rare earth elements in the alloy matrix has an upper limit value, and the rare earth elements in the temperature-correcting alloy are possibly consumed by oxygen in the atmosphere along with the extension of time. Further, if the oxygen content in the space 7 in contact with the temperature correcting alloy can be reduced relative to the ambient atmosphere outside the whole alloy temperature correcting device 9, the amount of oxygen entering the alloy matrix lattice from this atmosphere can be reduced, achieving a function similar to that of rare earth incorporation, or equivalently, adding more rare earth to the alloy matrix. Further, if the oxygen content (oxygen partial pressure) in the space 7 in contact with the temperature correcting alloy can be reduced to a very low level, there may be a case where the alloy base does not absorb dissolved oxygen from the atmosphere, that is, the oxygen in the atmosphere does not have any influence on the melting point of the alloy base.
The partial structure of the schematic cross-sectional structure of the alloy temperature correcting device provided by the invention is partially enlarged, and the enlarged partial structure is shown in fig. 2, wherein a first gap structure 10 is formed by a small container 1 and a small container cover 2, and a second gap structure 11 is formed by a large container 3 and a large container cover 4. It can be seen from the first gap structure 10 of fig. 2 that there is still a fine gap between the small container 1 and the small container cover 2 after the small container cover 2 is covered, and from the second gap structure 11 of fig. 2 that there is also a fine gap between the large container 3 and the large container cover 4 after the large container cover 4 is covered.
In the alloy temperature correcting device 6 shown in fig. 1, after the temperature correcting alloy 5 is placed, the volume of the space I7 is small, and the active rare earth element in the temperature correcting alloy can absorb trace oxygen in the atmosphere of the space I7 to generate rare earth oxide, so that the oxygen content in the atmosphere of the space I7 is extremely low. The oxygen concentration in the atmosphere 9 outside the alloy temperature correcting device is relatively high, the oxygen concentration in the atmosphere 8 in the space is relatively low, the oxygen concentration in the atmosphere 7 in the space is relatively lowest, oxygen concentration differences (gradients) exist between the oxygen concentration differences, the oxygen with higher concentration in the atmosphere 9 outside the alloy temperature correcting device needs to be diffused into the atmosphere 8 through the gap structure 11, then can be slowly diffused into the inner space of the small container 1 through the gap structure 10, finally can enter the temperature correcting alloy matrix, compared with the condition that the alloy is directly contacted with the external atmosphere, the oxygen diffusion process needs longer time because of resistance, even if part of oxygen enters the temperature correcting alloy matrix, rare earth metal elements in the temperature correcting alloy can react with oxygen in crystal lattices to generate stable high-melting-point oxide precipitates, so that the melting point of the temperature correcting alloy is not influenced by trace oxygen in the atmosphere in the furnace during the use, and the temperature correcting precision is ensured.
The industrial kiln may need to be subjected to complex and changeable atmospheres such as low temperature-high temperature-low temperature, vacuum-low pressure-normal pressure-high pressure and the like in the whole process of processing workpieces and products. By using a sealed vacuum pumping or an inflatable protection seal for the temperature correcting alloy, the temperature correcting alloy can be protected from the influence of trace oxygen in the external environment atmosphere, but cannot adapt to such complex pressure and temperature environment changes, for example, the temperature measuring device is sealed and vacuumized at low temperature, the temperature measuring device can collapse and crack to fail when the temperature measuring device is in high temperature and high pressure, the temperature measuring device is sealed and inflated at low temperature, and the device can fail when the temperature measuring device is in high temperature and vacuum. The alloy temperature correcting device has the advantages that the alloy temperature correcting device is provided with the gap structure I10 and the gap structure II 11, when pressure differences exist between the small container 1 and the large container 3 and between the large container 3 and the external environment atmosphere in the heating, cooling and pressurizing processes, atmosphere exchange can be carried out between the small container 1 and the large container 3 through the gaps under the driving of the pressure differences, namely, gas can enter and exit the container through the gaps between the container and the cover, so that the pressure balance between the atmosphere inside the container and the external atmosphere is realized, the possible damage of the pressure change of the atmosphere inside the kiln to the alloy temperature correcting device is avoided, the problems that the temperature correcting device is complex and has narrow adaptability due to complete sealing are solved, and the alloy temperature correcting device 6 can realize accurate temperature correction and temperature measurement under various pressure conditions from negative pressure to positive pressure of low oxygen atmosphere and can be widely applied to the temperature correction and temperature measurement of an industrial kiln.
If in a process, when the oxygen partial pressure is less than or equal to 400Pa, the vacuum absolute pressure is sometimes less than 0.001Pa, and the pressurizing pressure sometimes exceeds 2500bar, because the alloy temperature correcting device adopts the scheme of the invention, accurate temperature correction and temperature measurement can be realized, if a completely sealed scheme is adopted, a proper sealing material is difficult to find, and the alloy temperature correcting device can bear the great change of the external high temperature and pressure at the same time without failure.
In order to ensure the service life of the installed temperature detector of the industrial furnace, and also the factors of convenience in feeding and discharging, ensuring the cleanness of the detector and the like, the position of the temperature detector is usually far away from materials and workpieces processed by the industrial furnace, and the temperature detector is more inconvenient to penetrate into the materials and the workpieces, so that the temperature measured by the temperature detector is usually deviated from the actual temperature of the materials and the workpieces, and the error is larger. The alloy temperature correcting device developed by the invention can be placed together with materials and workpieces to be processed, even placed in the materials and the workpieces, and the actual temperature of the materials and the workpieces measured in situ can be obtained according to the change of the shape of the alloy temperature correcting device after the heating process is finished.
The alloy temperature calibration device and the alloy temperature calibration method are based on the proper use amount of the temperature calibration alloy and the proper container shape matching design, so that the alloy is melted into a sphere under the action of surface tension, and the temperature calibration and temperature measurement functions are realized. If the amount of the temperature correcting alloy 5 is large while the volume of the capsule 1 is small, the amount of the liquid after the melting of the temperature correcting alloy 5 exceeds the amount required to fill the bottom of the whole capsule 1, in which case the shape after the melting-solidification of the temperature correcting alloy 5 depends on the shape of the bottom of the capsule 1. Under the condition, according to the condition that the bottom of the container is filled after solidification, whether the temperature correcting alloy is molten or not can be judged, and the aims of temperature correction and temperature measurement are achieved.
In accordance with the principles set forth above, the detailed implementation of the present invention is summarized as follows:
according to a first aspect of the present invention, the present invention provides the following technical solutions:
The rare earth doped Cu-Ni temperature correcting alloy consists of Ni 0-99.995wt%, RE 0.005-1.5wt% and Cu and inevitable impurity elements for the rest.
Specifically, the mass percentage of Ni in the rare earth-doped copper-nickel temperature-correcting alloy can be any one or a range between any two of 0wt%、0.05wt%、0.1wt%、0.2wt%、0.5wt%、1wt%、2wt%、3wt%、4wt%、5wt%、6wt%、7wt%、8wt%、9wt%、10wt%、20wt%、30wt%、40wt%、50wt%、60wt%、70wt%、80wt%、90wt%、99.995wt%, and the mass percentage of RE in the rare earth-doped copper-nickel temperature-correcting alloy can be any one or a range between any two of 0.005wt%、0.01wt%、0.02wt%、0.03wt%、0.04wt%、0.05wt%、0.1wt%、0.2wt%、0.3wt%、0.4wt%、0.5wt%、0.6wt%、0.7wt%、0.8wt%、0.9wt%、1wt%、1.1wt%、1.2wt%、1.3wt%、1.4wt%、1.5wt%.
As a preferable scheme of the rare earth-doped copper-nickel temperature correcting alloy, the rare earth-doped copper-nickel temperature correcting alloy has a fixed melting point (namely, the melting point of the rare earth-doped copper-nickel temperature correcting alloy with fixed components is fixed and is determined by the components of the alloy), and the melting point range is 1084.6-1455 ℃.
As a preferred embodiment of the rare earth doped copper nickel temperature correcting alloy, RE is one or any combination of at least two of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.
As a preferable scheme of the rare earth-doped copper-nickel temperature correcting alloy, the rare earth in the rare earth-doped copper-nickel temperature correcting alloy can react with oxygen in alloy crystal lattices to generate stable high-melting-point oxide precipitates, so that the melting point of the temperature correcting alloy is not influenced by trace oxygen in the atmosphere inside a kiln during the use period, and the temperature correcting precision is ensured.
According to a second aspect of the present invention, the present invention provides the following technical solutions:
The preparation method of the rare earth doped copper-nickel temperature correction alloy comprises the following steps:
And 0, formulating a rare earth doped copper-nickel temperature correction alloy formula according to the target melting point, and marking the formula number as x.
And step 1, weighing copper, nickel and rare earth raw materials with required mass according to the requirements of a formula x in percentage by mass. The purity of copper and nickel raw materials is more than 99.99%, the shape is not limited, the shape of the preferable raw materials convenient to smelt is granular, block and flake, the purity of rare earth raw materials is more than 99.5%, and the preferable raw materials convenient to smelt are corresponding rare earth particles, rare earth copper master alloy and rare earth nickel master alloy.
And 2, placing the copper raw material and the nickel raw material into a cleaned vacuum induction melting furnace melting crucible, wrapping the rare earth raw material with copper foil (the mass of the copper foil is measured in the total copper content of the temperature correcting alloy), and placing the wrapped rare earth raw material into a vacuum induction melting furnace feeding device. The method comprises the steps of opening a switch of a power control cabinet, opening a switch of a cooling circulating water pump, covering a furnace cover of a vacuum induction smelting furnace, closing a furnace mouth lock ring, closing an air inlet valve and an air outlet valve, operating a control panel of the vacuum induction smelting furnace to vacuumize until the vacuum degree is below 10Pa, closing the vacuum pump and the valve, filling argon with the purity of more than 5N to absolute pressure of 10 kPa, vacuumizing again until the vacuum degree is below 10Pa, heating copper and nickel raw materials in a smelting crucible by slowly increasing the power until the copper and nickel raw materials in the smelting crucible are melted into liquid, throwing rare earth raw materials in a throwing device into the smelting crucible by using a rocker, slightly reducing the power until the liquid copper and nickel alloy rolls evenly, rotating a rotating rod inwards to rapidly cast the liquid alloy in the smelting crucible into a die, reducing the power to 0, sequentially closing the switch of the power control cabinet, keeping the circulating water pump on until the temperature of the smelting furnace is lower than 50 ℃ and taking out the rare earth copper alloy from the die to obtain the cast ingot a (x).
The smelting method is not limited to the vacuum induction furnace smelting method, and the alloy may be smelted by suspension smelting, arc smelting or the like, and the purpose of smelting is to melt copper, nickel and rare earth at high temperature to form a uniform alloy. The atmosphere during smelting is required to be controlled, impurities such as oxygen, nitrogen and the like in the atmosphere are reduced as much as possible, and raw materials with high purity are used, so that the rare earth loss during smelting and the impurity content in the final alloy are reduced.
It is generally known to those skilled in the art of smelting that during the smelting of copper alloys, certain amounts of RE are added to clean the alloys from low melting point impurities such as sulfur (95C), phosphorus (44C), selenium (220C), tin (232C), bismuth (271C), lead (327C), arsenic (818C) in principle that these low melting point elements react with rare earth metals to form high melting point compounds. When the rare earth-doped copper-nickel temperature correction alloy is smelted, the added rare earth has similar effect, and can purify and reduce impurity elements such as oxygen, phosphorus, sulfur, arsenic, antimony, lead, bismuth and the like in the alloy, so that the melting point of the alloy is more stable.
And 3, annealing the smelted alloy ingot a (x) in vacuum atmosphere, inert atmosphere or hydrogen atmosphere to further homogenize the alloy, wherein the highest heat preservation temperature of the annealing process can be 20-400 ℃ lower than the melting point of the ingot a (x), and the heat preservation time is not limited. The annealing temperature is usually controlled to be 30-200 ℃, preferably 30-150 ℃ and most preferably 50-100 ℃ lower than the melting point temperature, the heat preservation time is usually 2-48h, the heat preservation time is preferably 4-24h and the heat preservation time is most preferably 6-12h.
And 4, removing the surface layer of the alloy ingot a (x) which is more than 1 mm thick and contains more impurities and is easy to dirty by using machining equipment to obtain a pure and uniform alloy ingot a (x).
And 5, processing the pure and uniform alloy cast ingot a (x) into filaments or flakes, and crushing the filaments or flakes into short filaments or flakes with any dimension size smaller than 6mm by using a shearing tool or equipment to obtain the rare earth doped copper-nickel temperature correcting alloy a (x).
In the step 4 and the step 5, the machining process does not use media such as cooling liquid and the like so as not to introduce impurities to pollute the alloy, and meanwhile, the machining speed needs to be controlled so as to prevent serious oxidation caused by overhigh temperature of the alloy. Care should also be taken to avoid contamination of the alloy with other extraneous matter when crushing the alloy with a shearing tool or apparatus.
And 6, measuring the melting point of the rare earth doped copper-nickel temperature correcting alloy a (x). The melting point temperature of alloy a (x) is determined by methods well known to those skilled in the art, such as using a DSC thermogram, as follows:
Melting points of rare earth doped copper nickel master alloy a (x) were measured using a Netzsch DSC 449 F5 thermal analyzer. During measurement, the shielding gas and the carrier gas source are argon with the purity of 99.999%, and after the argon passes through the gas purification system, the oxygen content in the argon is not higher than 1ppm, and a trace oxygen analyzer is arranged in the gas system to monitor the oxygen content in the gas in real time. The argon flow is 30mL/min during measurement, in order to further reduce the oxygen content in the atmosphere of the thermal analyzer and improve the measurement accuracy of the melting point, a zirconium ring is placed on a DSC bracket during measurement, the heating speed is 10K/min, and the high-purity alumina crucible is calcined in clean air at 1400 ℃ for 3 hours before use. First, a thermal analyzer was calibrated according to ASTM E967 using pure metallic gold, cobalt with a purity of 99.999% or more. The melting points of high purity gold, copper, nickel and cobalt are 1064.18 ℃, 1084.62 ℃, 1455 ℃ and 1494 ℃ respectively according to the ITS-90 international temperature scale. After the DSC thermal analyzer is calibrated, the melting point of pure nickel (purity 99.999%) is measured 5 times, and the melting point of pure nickel is 1454.9-1455.5 ℃, so that the accuracy of the melting point measurement by the thermal analyzer in the vicinity of the temperature range can be roughly considered to be + -0.3 ℃.
When the melting point of the rare earth doped copper-nickel temperature correcting alloy a (x) is measured, the mass of an alloy sample is 15-20 mg each time, the alloy sample is measured for 3 times according to the ASTM E794 standard, and the average value is taken as the melting point of the alloy to be measured and expressed as T a(x) ℃.
Step 7, the temperature-correcting alloy atmosphere sensitivity evaluation program developed by the invention is adopted to evaluate the sensitivity of the melting point of the rare earth-doped copper-nickel temperature-correcting alloy a (x) to oxygen in the atmosphere, and the specific evaluation method is as follows:
the sensitivity of the master alloy to atmosphere was evaluated using a Netzsch DSC 449 F5 thermal analyzer. During measurement, the shielding gas and the carrier gas source are argon, and after passing through the gas purification system or the oxygenation system, the oxygen content in the argon can be adjusted within the range of less than 1ppm to 500ppm, and a trace oxygen analyzer is arranged in the gas system to monitor the oxygen content in the gas in real time. The method comprises the steps of performing ASTM E794 standard, taking 15-20 mg of alloy sample, loading the sample by using a high-purity alumina crucible without a cover, calcining for 3 hours in clean air at 1400 ℃, controlling the oxygen content in argon to be E ppm, heating from room temperature to T h ℃ at a temperature rising rate of 30 ℃ per minute, keeping the temperature for a certain time S min at T h ℃ to enable the alloy sample to fully react with oxygen in an argon atmosphere at a temperature close to the melting point of the alloy, evaluating the sensitivity of the melting point of the alloy to oxygen, heating to (T h +80) ° at a temperature rising rate of 10 ℃ per minute, measuring the melting point of the alloy, keeping the temperature for 5min at (T h +80) °, directly cooling to 50 ℃, ending the measurement, taking out the crucible and the sample from a thermal analyzer, and observing whether the sample is spheroidized or not, and the state of surface color and the like. The above evaluation method is designated PT h -E-S, as in P1054.5-5-20, where 1054.5 denotes a soak temperature of 1054.5 ℃,5 denotes an oxygen content in argon of 5 ppm, and 20 denotes a soak time of 20 min.
The melting point temperature value of alloy a (x) measured under the above conditions is recorded as T a(x)[PTh -E-S DEG C. In evaluating the atmosphere sensitivity of a specific alloy, such as alloy a (x), (T h +30) ° is usually equal to or close to the melting point T a(x) ℃ of the alloy, E represents the oxygen content in argon, 0, 5, 20 ppm and the like are selected in detection, the larger the value is, the larger the oxygen content in the atmosphere is indicated, wherein '0' represents the zero oxygen content in the atmosphere (strictly described as extremely low oxygen content) is measured, namely, the oxygen content is smaller than 0.5 ppm before the argon enters a thermal analyzer after purification, the display value of a micro oxygen analyzer is usually 0.2-0.5 ppm (close to the lower limit of measurement of the instrument), in order to further control and reduce the oxygen content in the thermal analyzer, the zirconium ring is placed on a DSC bracket to absorb oxygen in measurement, S represents the heat preservation time of T h ℃ is usually selected to be 20, 40min and the like, and the larger the value is the longer the reaction time between the calibration alloy and the oxygen in the atmosphere is in the condition of approaching the melting point temperature without melting.
Before formal measurement, the temperature of a DSC thermal analyzer is calibrated by using metallic silver and copper with the purity of more than 99.999 percent according to the ASTM E967 standard, so that the measurement accuracy of the melting point is ensured.
The alloy melting point under the above conditions was measured 3 times under the same conditions, and the average value was taken as the alloy melting point under the above conditions, recorded as T a(x)[PTh -E-S ]. Degree.C, and the sensitivity of the alloy to oxygen in the atmosphere was evaluated by comparing the deviation value with the normal melting point T a(x). Degree.C of the alloy.
After the above-mentioned atmosphere sensitivity evaluation measurement of the alloy sample, if necessary, particularly when a phenomenon such as remarkable oxidation of the sample surface is observed, the microscopic state of the sample surface can be confirmed by using a Scanning Electron Microscope (SEM), and the surface components can be analyzed by using an energy scattering X-ray spectroscopy (EDS).
According to a third aspect of the present invention, the present invention provides the following technical solutions:
a temperature calibrating and measuring method using the rare earth doped copper-nickel temperature calibrating alloy comprises the following steps:
Step 1, estimating the temperature range of the environment of the temperature measuring position, which is needed to be corrected, determining the lower limit temperature to be T min ℃ and the upper limit temperature to be T max ℃, and if the temperature range of the environment of the temperature measuring position, which is needed to be corrected, is estimated to be possible to be 1390-1420 ℃, then T min℃=1390℃、Tmax ℃ is equal to 1420 ℃.
And 2, selecting n rare earth doped copper-nickel temperature correcting alloys with gradually increased melting points according to the temperature correcting and measuring precision requirements, wherein the alloy with the lowest melting point of T a(1) ℃ and the alloy with the highest melting point of Ta(n)℃,Ta(1)＜Ta(2)＜Ta(3)＜…＜Ta(n-2)＜Ta(n-1)＜Ta(n),Ta(1)<1390、Ta(n)>1420. can be arranged in a mode of gradually decreasing the melting points, and the final temperature correcting and measuring effects are not affected.
And 3, placing a proper amount of the n temperature correcting alloys with different melting points selected in the step 2 into n small containers, adding a container cover to each small container, sequentially stacking the small containers (filled with alloy) into a large container according to the ascending or descending order of the melting point temperature of the alloy, and assembling the large container and the container cover into an alloy temperature correcting device { T a(1)~Ta(n) }, as shown in figure 1.
And 4, placing the single or multiple alloy temperature calibrating devices { T a(1)~Ta(n) } in the step 3 at the position points needing temperature calibration and measurement in the equipment. The alloy temperature correcting device can be placed together with materials to be processed, and can be placed inside the materials for in-situ temperature correction if needed.
And 5, setting a heating program according to the normal production process requirement, and starting the equipment to enter an operating state. If the apparatus is equipped with a temperature measurement and control system, the maximum process temperature T s ℃ is set, and the measured maximum temperature is T c ℃.
And 6, after the equipment is cooled to normal temperature, taking out the alloy temperature correcting device, observing the state of the alloy temperature correcting device, and judging the real temperature T z ℃ of the position of the alloy temperature correcting device, wherein the real temperature T z ℃ is shown in fig. 3. The true temperature T z is determined by:
If the alloy temperature correcting device { T a(1)~Ta(n) } is observed to be numbered 1, 2, and the n-3 alloy is melted into spheres, the n-2, n-1 and n alloy are not melted and keep the original flake shape, and the true temperature T z ℃ at the position is judged to be between [ T a(n-3),Ta(n-2) ] DEGC, and the invention considers T z=(Ta(n-3)+Ta(n-2))/2.
If 6 temperature correcting alloys with gradually increased melting points are placed in a small container, the alloy temperature correcting devices { T a(1)~Ta(6) } are formed by stacking the alloy in a large container according to the melting points from low to high as shown in figure 1. The device is placed at a kiln position needing temperature correction and measurement, after the device is subjected to a thermal process, the alloy temperature correction device is taken out, the alloy melting state in a small container is determined, a schematic cross-sectional structure diagram of the alloy temperature correction device after use is shown in figure 3, 3 alloys of a (1), a (2) and a (3) are melted and spheroidized, 3 alloys of a (4), a (5) and a (6) are not melted, and the shape is not changed obviously, so that the true temperature value T z=(Ta(3)+Ta(4))/2 is determined.
And 7, according to the highest temperature T c and the actual temperature T z of the position of the alloy temperature correcting device, which are measured by the equipment with temperature measuring system in the step 5 and the step 6, a temperature difference delta T=T z-Tc can be obtained, wherein the delta T is the temperature to be compensated by the equipment, and the equipment temperature is adjusted according to the delta T, such as process temperature compensation is set, or the kiln is maintained.
The alloy temperature correcting device after use can be reused after cleaning the containers and the container covers if the containers and the container covers are not damaged.
As the preferable scheme of temperature calibration and temperature measurement by using the rare earth-doped copper-nickel temperature calibration alloy, the rare earth-doped copper-nickel temperature calibration alloy can be used for temperature calibration and temperature measurement in a low-oxygen atmosphere with the oxygen partial pressure of less than or equal to 400 Pa.
As the preferable scheme of temperature calibration and temperature measurement by using the rare earth doped copper-nickel temperature calibration alloy, the invention comprises a vacuum atmosphere, an inert gas atmosphere and a reducing atmosphere. Preferably, the low oxygen atmosphere includes a vacuum atmosphere, an inert gas atmosphere (inert gas means group 0 elements of the periodic table including helium, neon, argon, krypton, xenon, radon), a reducing atmosphere (e.g., hydrogen, etc.). Further preferably, the low oxygen atmosphere refers to an atmosphere having an oxygen partial pressure of 200 Pa or less, and the atmosphere may be at a pressure ranging from negative to positive, e.g., the absolute pressure of the vacuum furnace may be less than 0.001Pa and the pressure of the HIP furnace may be in excess of 2000bar.
Compared with the prior art, the temperature calibrating and measuring method using the rare earth-doped copper-nickel temperature calibrating alloy has the following characteristics:
(1) The alloy temperature correcting device does not need vacuum or inflation protection air seal, the small container and the large container of the alloy temperature correcting device after use can be repeatedly used for a plurality of times after being cleaned, and the temperature correcting and measuring process does not need to interrupt the normal production work of equipment.
(2) The temperature calibrating and measuring device has simple structure, the temperature calibrating and measuring process does not need to load and unload thermocouples, install the temperature measuring device and other complicated operations, the temperature calibrating and measuring data can be obtained by visually observing whether the temperature calibrating alloy is melted and spheroidized, and the temperature calibrating and measuring process can be carried out along with normal production, thereby realizing in-situ temperature calibrating and measuring.
(3) The temperature correcting and measuring applicability is wide, the rare earth in the rare earth-doped copper-nickel temperature correcting alloy can absorb oxygen in the atmosphere of the alloy temperature correcting device, so that the oxygen content in the atmosphere of a small container of the alloy temperature correcting device is reduced compared with the external environment, and meanwhile, the small container with a cover and the large container with a cover slow down the diffusion of the oxygen in the environment into the small container, so that the temperature correcting alloy in the alloy temperature correcting device is not easily influenced by the oxygen in the atmosphere, and the alloy temperature correcting device can be applied to the temperature correction and measurement of various industrial kilns under the low-oxygen atmosphere (including vacuum atmosphere, inert gas atmosphere and reducing atmosphere) with the oxygen partial pressure less than or equal to 400 Pa. In addition, the interior of the alloy temperature correcting device can exchange atmosphere with the external environment through the micro gap between the container and the container cover, so that pressure balance is realized, the speed of oxygen in the atmosphere entering the interior can be controlled, the temperature correction and measurement under various pressure conditions from negative pressure to positive pressure of the low-oxygen atmosphere are realized, the damage of the pressure change of the atmosphere in the kiln to the temperature measuring device is avoided, and the temperature correcting and measuring method can be widely applied to the temperature correction and measurement of the industrial kiln.
The technical scheme of the invention is further described below by combining specific embodiments.
Example 1
In the embodiment, the better rare earth addition is determined by evaluating the sensitivity of copper-nickel alloys with different rare earth addition to oxygen in the atmosphere.
According to the preparation method of the rare earth-doped copper-nickel temperature correction alloy, 5 copper-nickel alloy ingots with the mass percent of rare earth Ce of 0.00%, 0.02%, 0.15%, 0.50% and 2.00% are prepared by smelting in a vacuum induction smelting furnace, and the 5 alloys are respectively cut and sheared into short filiform samples with the lengths of not more than 6mm by using machining equipment and shearing tools or equipment, so that various tests are convenient to carry out. Melting points of the above 5 alloys were measured according to the alloy melting point measuring method of the present invention, and specific components of the alloys and corresponding melting points are shown in table 2. The analysis of the composition of the cut ECG-03 and ECG-05 alloy samples using EDS is shown in FIGS. 4 and 5, and the energy spectrum results show that a small amount of rare earth Ce is successfully doped into the copper-nickel alloy.
Melting point of copper-nickel alloys with different rare earth Ce contents prepared in Table 2
By comparing Table 2, it was found that the amount of rare earth Ce added to the copper-nickel alloy was not more than 0.15%, and the melting points thereof were hardly affected, i.e., the melting points of the alloys ECN-01, ECN-02, ECN-03 were almost the same (melting points differ by 0.3 ℃ C., within the melting point tolerance). The addition of rare earth Ce slightly reduces the melting point of the copper-nickel alloy when the addition of the rare earth Ce is 0.50 percent, and obviously reduces the melting point of the copper-nickel alloy when the addition of the rare earth Ce is increased to 2.00 percent (see Table 2), and compared with the ECN-03 alloy, the melting point of the copper-nickel alloy is reduced by 10.1 ℃.
The sensitivity of ECN-01, ECN-02, ECN-03, ECN-04, ECN-05 alloys to oxygen in the atmosphere was evaluated according to the "temperature-correcting alloy atmosphere sensitivity evaluation program" evaluation method of the present invention, and the evaluation results are shown in Table 3.
Table 3 data for evaluating sensitivity of copper-nickel alloys with different rare earth Ce contents to oxygen in atmosphere
Note that "/" in the table represents no accurate value, and "+" in the evaluation column for sensitivity to oxygen in the atmosphere represents that the more affected by oxygen in the atmosphere.
As can be seen from Table 3, when the atmosphere sensitivity evaluation condition was set to P1415.0-0-40, i.e., the first step soak temperature was set to 1415.0 ℃, the soak time was set to 40 min, the second step soak temperature was set to 1495.0 ℃, the soak time was set to 5 min, and the oxygen content in the whole atmosphere was set to 0 ppm (strictly described as extremely low oxygen content), the melting temperatures of ECN-01, ECN-02, ECN-03 alloys were all not affected by, or only slightly affected by, oxygen in the atmosphere, there was a melting endothermic peak, became spherical, the sensitivity to oxygen in the atmosphere was evaluated as "+", the melting point of ECN-04 was increased by 2.4 ℃, the sensitivity to oxygen in the atmosphere was evaluated as "+", the exact value of T a(x)[PTh -E-S ] could not be determined for ECN-05, and the strongly sticking crucible became hemispherical after the evaluation test because relatively more rare earth Ce, which was more active than Ni, was strongly blocked on the crucible wall after the reaction with alumina alloy at high temperature, and formed as "+" sensitivity to oxygen in the atmosphere was evaluated as "+".
When the evaluation condition is set to be P1415.0-20-40, that is, the oxygen content in the atmosphere is 20 ppm, the T a(x)[PTh -E-S DEG C of the ECN-01 alloy without adding rare earth Ce is reduced by 5.2 ℃ compared with the T a(x) ℃, has melting heat absorption peak, is spherical, sensitivity to oxygen in the atmosphere the evaluation was "+++". ECN-02 alloy added with trace rare earth Ce (0.02% by mass) is similar to ECN-01 alloy, and T a(x)[PTh -E-S DEG C is reduced by 3.7 ℃ compared with T a(x) DEG C, because the rare earth content in the ECN-02 alloy is low, after rare earth elements are completely consumed by reaction with oxygen, redundant oxygen enters a copper-nickel alloy matrix lattice to become free oxygen, the melting point of the alloy is reduced, and the sensitivity to oxygen in the atmosphere is evaluated as "++ + +".
ECN-05 alloy added with 2.00% of rare earth Ce can not judge the accurate value of T a(x)[PTh -E-S, mainly because relatively more active rare earth Ce exists in ECN-05 alloy, the rare earth Ce reacts with an alumina crucible at 1415.0 ℃ for a long time in a heat preservation mode, the rare earth Ce is strongly adhered to the wall of the crucible, and because more active rare earth exists, the Ce reacts with oxygen in the atmosphere more strongly, the shape of the Ce is prevented from being changed, and the sensitivity to oxygen in the atmosphere is evaluated as "++ + +". SEM and EDS energy spectrum analysis are carried out on ECN-05 alloy subjected to P1415.0-20-40 atmosphere sensitivity evaluation, as shown in fig. 6 and 7, the SEM observes that the surface of a sample is seriously oxidized, an oxide film is generated, no obvious shape change occurs, and the energy spectrum analysis is carried out on the surface of the sample which is not contacted with a crucible, so that the main component of the oxide film is cerium oxide.
The ECN-03 alloy added with 0.15% of rare earth Ce is evaluated under the same conditions, the rise of T a(x)[PTh -E-S ] °C is reduced by 0.2 ℃ compared with the rise of T a(x) ℃ (within the range of the allowable melting point error), the alloy has a melting endothermic peak, is spherical, the melting point and the shape of the alloy after melting are not affected by oxygen in the atmosphere, and the sensitivity to oxygen in the atmosphere is evaluated as "+". The proper amount of rare earth Ce can absorb oxygen entering the alloy from the ambient atmosphere, become rare earth oxide precipitate with high melting point and high stability, purify free oxygen in alloy crystal lattice and control the influence of oxygen in the atmosphere on the alloy Jin Rongdian. The SEM and energy spectrum analysis results of the ECN-03 alloy sample surface after atmosphere sensitivity evaluation are shown in fig. 8 and 9, and it can be found from fig. 8 that the ECN-03 alloy sample surface is relatively flat, has no obvious oxide layer and is in a perfect sphere shape as a whole, and the energy spectrum analysis results of fig. 9 show that the surface has more oxygen and Ce, and compared with fig. 4 and 9, the ECN-03 alloy sample surface has higher content of Ce after being heated and melted, and the Ce in the matrix tends to migrate to the surface in the heating process.
Therefore, when rare earth is added into the rare earth-doped copper-nickel temperature correction alloy in a mass percentage of about 0.15%, the melting temperature and the melting state are hardly influenced by oxygen in the atmosphere, namely, the gas sensitivity is the best.
Example 2
The embodiment provides a series of rare earth doped copper-nickel temperature correcting alloys with different melting point temperatures.
According to the preparation method of the rare earth-doped copper-nickel temperature correcting alloy, the rare earth-doped copper-nickel temperature correcting alloy with different melting points is prepared by changing the nickel content in the alloy and using a vacuum induction melting furnace and a shearing tool or device. Wherein the mass percentage of rare earth is 0.15 percent, and the added rare earth metals are Ce, la, Y, lu respectively.
The melting point of the alloy according to the method for measuring melting point of the alloy of the present invention was measured using a Netzsch DSC 449 F5 thermal analyzer, and the specific results are shown in table 4.
Rare earth doped copper-nickel temperature correction alloy prepared in table 4 with gradient melting point temperature
Example 3:
the rare earth doped copper-nickel alloy temperature correcting and measuring method is applied to correct the real temperature of the center position of the hard alloy sintering furnace.
The alloy short wire-shaped alloys with the numbers of CN-22, CN-21, CN-20, CN-19, CN-18, CN-17, CN-16 and CN-15 prepared in the embodiment 2 are assembled into a similar alloy temperature measuring device { 1401.1-1420.2 }, the alloy temperature measuring device { 1401.1-1420.2 } is placed at the central position of a cemented carbide sintering furnace with the number of A-03# and cemented carbide compacts to be sintered are placed at other positions according to the alloy temperature measuring device form provided by the specification of the present invention. According to the requirements of the sintering process of the hard alloy material, setting the highest sintering temperature to be 1420.0 ℃ which is the temperature T c, and preserving the temperature for 150min at the temperature, wherein the sintering atmosphere is vacuum. After the furnace temperature is reduced to below 50 ℃, taking out the hard alloy product and the temperature correcting device together, observing the shape change of the alloys, and finding that the shapes of CN-22, CN-21, CN-20, CN-19 and CN-18 alloys are obviously changed to be spherical, and the shapes of CN-17, CN-16 and CN-15 alloys are not obviously changed or are short and filiform. The melting points of CN-18 and CN-17 alloy are 1410.5 and 1413.1 respectively, the highest real temperature of the central position of the sintering furnace is determined to be 1410.5-1413.1 ℃ according to the shape change, the highest real temperature of the central position can be considered to be 1411.8 +/-1.3 ℃ by taking the intermediate value, namely the temperature of T z ℃, and the temperature of T z℃-Tc ℃ =deltaT ℃ is obtained to be-8.2 ℃. In the next sintering of the product, the required actual sintering temperature 1420.0 ℃ can be achieved by setting the highest sintering temperature of the A-03# hard alloy sintering furnace to 1428.2 ℃ in control software.
According to the method, the real temperature of the central position of the A-03# hard alloy sintering furnace is obtained through in-situ calibration under the condition that normal production of the sintering furnace is not affected, and then the really needed sintering temperature can be achieved through simply changing the temperature setting value in control software. The temperature adjustment is carried out regularly, so that the real sintering temperature of the A-03# hard alloy can be kept consistent for a long time, and the stable production of the product with reliable quality of the sintering furnace is realized.
In general, a plurality of sintering furnaces are arranged on the same production line, the alloy temperature calibration technology described by the invention is adopted to uniformly perform temperature calibration on all the sintering furnaces on the production line according to the method, and the temperature compensation is performed on each sintering furnace according to the temperature calibration result, so that the same real sintering temperature can be implemented for different sintering furnaces on the same production line. Therefore, the quality management work is carried out, the fluctuation range of the product performance index on the production line is reduced, and the enterprise is helped to achieve the aim of improving the product quality.
Example 4
The rare earth doped copper-nickel temperature correction alloy can truly reflect the real temperature field distribution of the hearth of the hard alloy sintering furnace, and can guide the point position deviating from the target temperature to carry out temperature correction.
The alloy temperature measuring devices { 1399.7-1431.1 } prepared in example 2 and having the numbers of CN-23, CN-21, CN-19, CN-17, CN-16, CN-15, CN-13 and CN-11 were assembled into a similar alloy temperature measuring device according to the form of the alloy temperature measuring device provided in the description of the invention, and the arrangement mode of the alloy in the crucible (the arrangement mode in the case of overlooking the crucible) is shown in Table 5.
TABLE 5 arrangement of alloys in crucible
The alloy temperature correcting device (1399.7-1431.1) is placed in a No. A-05 hard alloy sintering furnace, such as a first temperature measuring point 101, a second temperature measuring point 102, a third temperature measuring point 103, a fourth temperature measuring point 104, a fifth temperature measuring point 105, a sixth temperature measuring point 106, a seventh temperature measuring point 107, a eighth temperature measuring point 108, a ninth temperature measuring point 109, a tenth temperature measuring point 1010 and an eleventh temperature measuring point 1011, which are shown in fig. 10, wherein a front furnace door 21 and a rear furnace door 22 are used for displaying a furnace body structure so as to display the arrangement condition of the 11 temperature measuring points in the furnace body, and hard alloy pressed blanks needing sintering are placed at other positions. According to the requirements of the sintering process of the hard alloy material, the highest sintering heat preservation temperature is 1400 ℃, the temperature is kept for 90min, and the sintering atmosphere is vacuum. After the furnace temperature was lowered to 50 ℃ or below, the cemented carbide product was taken out together with the temperature correcting device, and the shape change of these alloys was observed (for example, the melting result of the temperature correcting alloy at the position point 1 is shown in fig. 11), and the result data is shown in table 6.
Table 6 shows real temperature data of each point of the hearth of the A-05# cemented carbide sintering furnace with the heat preservation temperature of 1400 DEG C
The temperature delta T required to be compensated for each point of the A-05# cemented carbide sintering furnace can be obtained according to the data in Table 6 and is shown in Table 7.
Table 7 sets the temperature delta T of the heat preservation temperature 1400 ℃ for compensating each position of the hearth of the A-05# hard alloy sintering furnace
Therefore, by placing rare earth-doped copper-nickel temperature correction alloy devices at different positions of the hearth of the hard alloy sintering furnace for temperature correction, the real temperature field distribution situation of the hearth of the hard alloy sintering furnace can be truly reflected, and the positions deviating from the target temperature can be guided for temperature correction. In this respect, the true temperature can be obtained by a rare earth doped copper-nickel temperature correcting alloy device. On the other hand, the heating element or the furnace compensation coefficient can be adjusted according to the temperature delta T to be compensated, so that the uniformity of the whole temperature field of the furnace chamber of the hard alloy sintering furnace can be realized, and the performance and quality consistency of the sintering products of the same furnace can be improved.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the content of the present invention or direct/indirect application in other related technical fields are included in the scope of the present invention.

Claims (10)

1. The application of the rare earth doped copper-nickel alloy in the temperature correction field is characterized in that the rare earth doped copper-nickel alloy comprises, by mass, 0-99.995% of Ni, 0.005-1.5% of RE, and the balance of Cu and unavoidable impurity elements, wherein the melting point range of the rare earth doped copper-nickel alloy is 1084.6-1455 ℃.
2. The use of a rare earth doped copper nickel alloy according to claim 1, wherein RE is one or any combination of at least two of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.
3. The use of a rare earth doped copper-nickel alloy according to any of claims 1-2 in the field of temperature calibration, wherein the method for preparing the rare earth doped copper-nickel alloy comprises the steps of:
step 0, formulating an alloy formula according to a target melting point;
step 1, weighing copper, nickel and rare earth raw materials with required mass according to the formula requirement in percentage by mass;
Smelting copper, nickel and rare earth raw materials to alloy and homogenize the materials, and obtaining rare earth doped copper-nickel alloy ingots;
Step 3, processing the rare earth doped copper-nickel alloy cast ingot, and crushing the cast ingot into a non-spherical shape to prepare a rare earth doped copper-nickel alloy for standby;
Step4, measuring the melting point T DEG C of the rare earth doped copper-nickel alloy;
And 5, evaluating the sensitivity of the rare earth doped copper-nickel alloy to oxygen in the atmosphere.
4. A temperature calibrating and measuring method, which adopts the rare earth doped copper-nickel alloy of any one of claims 1-2 in the application of the rare earth doped copper-nickel alloy in the temperature calibrating field, and is characterized by comprising the following steps:
step 1, estimating the environmental temperature range of a position needing temperature correction and temperature measurement, and determining the lower limit temperature of the temperature range to be T min ℃ and the upper limit temperature to be T max ℃;
Step 2, according to the temperature correction and measurement precision requirements, selecting n rare earth doped copper-nickel alloys with gradually increased melting points, wherein the lowest melting point is T a(1) ℃ and the highest melting point is Ta(n)℃,Ta(1)＜Ta(2)＜Ta(3)＜…＜Ta(n-2)＜Ta(n-1)＜Ta(n),Ta(1)<Tmin、Ta(n)>Tmax;
Step 3, assembling the n rare earth doped copper-nickel alloys with the gradually increased melting points and the container into an alloy temperature correcting device;
Step 4, placing a single or a plurality of alloy temperature calibrating devices in the step 3 at positions needing temperature calibration and temperature measurement;
Step5, setting a heating program according to the normal production process requirement, starting the equipment to enter an operating state, and measuring the highest temperature of the equipment by a temperature measurement system at a temperature of T c ℃;
step 6, after the equipment is cooled to normal temperature after operation, taking out the alloy temperature correcting device, observing the alloy state in the container, and judging the real temperature T z ℃ of the environment where the alloy temperature correcting device is positioned, so that temperature measurement is realized;
in step 7, T z-Tc =Δt, and Δt is the temperature to be compensated by the device, and the device temperature is adjusted according to Δt, so that temperature calibration is achieved.
5. The method for calibrating and measuring temperature according to claim 4, wherein the alloy temperature calibrating device in step 3 comprises:
n rare earth doped copper-nickel alloys with different melting points are placed in n small containers, each small container is placed in a large container with a container cover, and the large container is provided with a container cover.
6. The method for calibrating and measuring temperature according to claim 5, wherein the alloy does not wet the capsule, and the volume of the rare earth doped copper-nickel alloy placed in the capsule is 1/20-1/2 of the volume of the capsule.
7. The method for calibrating and measuring temperature according to claim 4, wherein the process of calibrating and measuring temperature is carried out along with normal production, and the alloy temperature calibrating device is placed together with a workpiece to be processed, so that normal production work is not affected, and in-situ temperature calibration and measurement are realized.
8. The method according to claim 4, wherein the actual temperature T z ℃ in the step 6 is determined by:
The alloy temperature correcting device is observed to be in the shape of a sphere when the alloy No. 1, 2 and the alloy No. n-3 are melted, the alloy No. n-2, n-1 and the alloy No. n are not melted and keep the original shape, and the actual temperature of the temperature correcting and measuring position is required to be between [ T a(n-3),Ta(n-2) ] DEGC, and then T z=(Ta(n-3)+Ta(n-2))/2 is considered.
9. The method for calibrating and measuring temperature according to claim 4, wherein the alloy temperature calibrating device can be applied to various industrial kilns for calibrating and measuring temperature under low oxygen atmosphere, and the alloy temperature calibrating device can protect the melting point of the internal alloy from oxygen in the external environment atmosphere without vacuum or protection gas filling for sealing.
10. The temperature calibrating and measuring method according to claim 9, wherein the alloy temperature calibrating device can calibrate and measure the temperature of the industrial furnace under various pressure conditions from negative pressure to positive pressure in the low-oxygen atmosphere, wherein the low-oxygen atmosphere is an atmosphere with oxygen partial pressure less than or equal to 400Pa, and the low-oxygen atmosphere comprises a vacuum atmosphere, an inert gas atmosphere and a reducing atmosphere.
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