JPH06145961A - Container for heat treatment of parts - Google Patents

Abstract

(57) [Summary] [Objective] To obtain a highly reliable container for heat treatment of a member, which can obtain a member of high quality after heat treatment. [Structure] The surface of a container accommodating a member to be heat-treated is coated with chromium, titanium, or zirconium, and at least a part of the coated member is converted to its oxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for heat treatment of members.

[0002]

2. Description of the Related Art In recent years, as plants have grown in size, electronic devices centering on semiconductor parts have become highly integrated, and systems have become highly functional, demands for materials and parts have become severe and sophisticated. In order to meet this demand, materials or parts are required to be highly purified while maintaining the price at an industrial level.

In general, these raw materials or parts are heat-treated by using a raw material which has been thoroughly examined and obtained by a melting method, a sintering method or a sintering / infiltration method in a predetermined atmosphere level. The product or semi-finished product is made after each process of processing and processing.

With respect to the raw materials thoroughly examined here, the raw materials having the target performance can be easily prepared industrially by the recent progress of the refining technology. The atmosphere in each step is an inert atmosphere such as vacuum, nitrogen, argon, or hydrogen, or a reducing atmosphere, so that high-performance equipment can be easily prepared economically.

Of these, the heat treatment process, for example, metal powders such as iron, nickel, chromium, titanium, tungsten, tantalum, and alloy powders such as stainless steel are generally used as raw material powders for powder metallurgy. A heat treatment container is indispensable for the heat treatment carried out during the production of the product, in order to support the raw material or parts during the heat treatment.

Conventional heat treatment containers include those made of graphite and those made of nitride such as boron nitride. The former utilizes the excellent reducing power of carbon at high temperatures, and the latter utilizes the property that nitrides at high temperatures are difficult to wet with many metals and is used industrially. Such a heat treatment container is formed into a predetermined shape so that the obtained parts and the like have a desired shape, and the parts and the like are housed inside and subjected to heat treatment.

[0007]

However, in the heat treatment step, it is not possible to easily prepare, on an industrial level, to accurately quantify and control various conditions at the moment of treatment.

The inventor of the present invention examined each of the above steps for the purpose of obtaining a sound material or part having a target performance, and found that the material or part is heated by heating during the heat treatment such as melting or sintering. It has been found that the physical and chemical states of the crucible and the sintering boat affect the quality of the material or parts obtained.

That is, since the raw material or component is inserted into or placed in a heat treatment container and subjected to heat treatment to obtain a product or a semi-finished product, the raw material or component is directly subjected to the heat treatment container graphite and the heat treatment. Will be in contact with each other. Therefore, there are cases where the material or component and the graphite exhibit a metallurgical reaction.

As a result, the material or part cannot be taken out from the heat treatment container in a sound form and is damaged. Not only that, but inconveniences such as destruction of the heat treatment container may occur.

In addition, there are cases where impurities in the heat treatment container diffuse and penetrate into the material or parts due to the metallurgical reaction, and the purity of the material or parts after the heat treatment is lowered.

Further, for example, ordinary graphite is porous, and a large amount of water and gas are present on the surface and inside thereof, so that this water and gas directly contact the surface of the material or component during the heat treatment. There may be inconvenience of contamination. Considering such a point, the use of conventional containers must be restricted depending on the atmosphere.

It is an object of the present invention to provide a highly reliable container for heat treatment of parts, which can obtain high quality parts and the like without causing damage and contamination of parts and the like to be heat treated.

[0014]

In order to achieve the above-mentioned object, the present invention is to coat the surface of a housing means for housing a member with any one of chromium, titanium and zirconium,
Since at least a part of the covering member is made of the oxide, it is possible to prevent inconveniences such as damage to the member and entry of impurities into the member.

[0015]

EXAMPLES Examples of the present invention will be described in detail below. Even with modern plants and systems, the quality of just one component can cause variations in performance or lack of desired functionality.

When the present inventors examined each of the above-mentioned steps, the above-mentioned variations in the electrical (or mechanical, chemical) performance of the plant or system show that the heat treatment step of the materials or parts used in these It was found to be correlated with.

In particular, it has been discovered that the above-mentioned variation in the performance of the plant or system can be suppressed by controlling the release of the generated gas for each of the raw materials constituting the material or the part.

Therefore, as a result of further detailed investigation of the heat treatment step, the present inventors found that the degree of variation in physical and chemical states of the heat treatment container which is in direct contact with the material or component during the heat treatment. , Has found that it has a significant impact on performance variations.

That is, it is suggested that a high-performance heat treatment container is indispensable for producing a sound material or component. Therefore, it is important that the heat treatment container is a heat treatment container that does not cause damage or contamination to the material or parts even by the heat treatment.

It is difficult to say that a graphite or nitride heat treatment container can produce sound materials or parts as described above. That is, regarding the former, for example, when iron, chromium, titanium or the like is selected as the material or part, the surface of the material or part is damaged or the heat treatment container is broken due to the formation of iron carbide, chromium carbide or titanium carbide. Is not preferable. As a technique for suppressing such metallurgical reaction, a technique for interposing an aluminum oxide fine particle layer between the two has been developed. However, water, gas present in the fine particle gaps or on the surface of the fine particles may affect iron, chromium, titanium, etc. to some extent, which may be an obstacle to the production of raw materials or parts in a sound state. On the other hand, with regard to the latter, there are problems that use is restricted depending on the atmosphere and that the decomposition temperature is relatively low.

Therefore, the inventors of the present invention manufactured a metallic Ti heat treatment container by using a high-purity Ti plate having a thickness of 3 mm. After the surface of the heat treatment container was extremely cleaned, the following trial production was attempted using this. Experiment (1) T using Ti obtained by forging after arc melting
An experiment in which a flange part made of i was heat-treated at 810 ° C. in a vacuum was conducted to obtain a target product or a semifinished product.

Experiment (2) 4 times the Ti powder which was sufficiently degassed
Ton / cm ² An experiment was conducted to heat a gear part made of Ti powder having a diameter of 42 mm, which was pressed in step 1, by heat treatment at 810 ° C. in a vacuum to obtain a target product or a semi-finished product.

As a result, in the former Ti flanged component (1), a strong mutual diffusion phenomenon was observed between the Ti heat treatment container and the Ti flanged component, and the Ti component could not be taken out from the container without damage. It was not possible to obtain a sound Ti part. However, there was no surface contamination of the Ti part and no intrusion of impurities into the inside.

On the other hand, in the latter (2) Ti gear parts,
Despite the same heat treatment, no strong mutual diffusion phenomenon like the former (1) was observed between the Ti heat treatment container and the Ti powder gear parts, and the Ti parts were not damaged. I was able to take it out of the container. Moreover, as in the former case (1), there was no surface contamination and no intrusion of impurities into the interior.

That is, the present inventors have conducted both experiments (1),
It was found that high-purity metal is useful as a container for heat treatment, except that the problem of surface damage of materials or parts is eliminated by (2). Moreover, considering the fact that the latter case (2) had a minor surface damage problem, the Ti powder was subjected to the heat treatment which was sufficiently degassed prior to the latter (2) experiment.
It is considered that the appropriate amount of the remaining surface gas acted on the surface of the heat-treating container whose surface was extremely cleaned, and an adequately wetted film was produced. As a result of microanalysis, the products were compounds of Ti, O, and C.

Furthermore, the inventors of the present invention used the highly purified Ti plate heat treatment container used in the above experiments (1) and (2) whose surface was extremely clean, based on the above results. As (3), an extremely thin Ti coating having a thickness of about 0.1 μm was previously formed on the surface of the vessel for heat treatment by an ion plating method to prepare a vessel for heat treatment. Experiment (1) using this heat treatment container,
When the same heat treatment as in (2) was performed, the Ti flange part, T
The i-powder gear part could be taken out, and the part had no surface contamination or intrusion of impurities into the inside.

As an experiment (4), while adjusting the atmosphere by the sputtering method, the thickness is about 0.1 μm, which is extremely thin (Ti-
O) A heat treatment container having a coating formed on graphite was produced. Using this heat treatment container, the same heat treatment as in Experiments (1) and (2) was performed. As a result, Ti flange parts and Ti powder gear parts could be taken out from the heat treatment container in a sound state without surface damage. , The parts had no surface contamination and no ingress of impurities into the interior.

In Experiment (5), a heat treatment container was produced in which a (Ti—O) coating having a thickness of about 90 μm was formed on graphite while adjusting the atmosphere by a sputtering method. When heat treatment similar to that in Experiments (1) and (2) was performed using this heat treatment container, a strong mutual interaction was observed between the heat treatment container and the Ti flange parts, and between the heat treatment container and the Ti powder gear parts. A diffusion phenomenon was observed, and it could not be taken out of the container without damage, and a sound Ti part could not be obtained.

As an experiment (6), while adjusting the atmosphere by the sputtering method, the thickness of (Ti-O) is about 0.01 μm.
A container for heat treatment was produced in which a coating was formed on graphite.
When this heat treatment container was used for the same heat treatment as in Experiments (1) and (2), the Ti flange component and the Ti powder gear component could be taken out from the heat treatment container in a sound state without surface damage. However, due to the fact that the thickness of the coating was not necessary, moisture and gas existing on the surface and inside of the graphite diffused to the Ti flange parts and Ti powder gear parts during heat treatment, and these surfaces It was not possible to obtain a sound Ti part because of contamination and invasion of impurities into the inside.

The present inventors have made new experiments (3), (4),
According to (5) and (6), even in a heat treatment container in which a metal coating is formed on the graphite heat treatment container, a product in a sound state without surface damage, surface contamination, and intrusion of impurities into the inside. It was found that a semi-finished product was obtained, and that if the thickness of the metal coating on the graphite heat treatment container was inappropriate, a strong interdiffusion phenomenon was observed, which was not preferable. Next, description will be made based on experimental data relating to the present invention.

First, a Cr target material for sputtering was manufactured by using Cr powder as a raw material. Cr for this raw material
The powder has an average particle diameter of 74 μm, Al content of 8 ppm, Si content of 15 ppm, V content of 2 ppm or less, Ca content of 2 ppm or less, oxygen content of 100 ppm, and nitrogen content of 30 ppm. This production was performed as follows. That is, using this Cr powder for raw material, the diameter is 2 inches and the length is 100 m.
A Cr molded body of m and 8 mm in thickness was obtained.

On the other hand, by using a Cr ingot for surface coating of a heat treatment container, various containers 2 having a Cr coating of a predetermined thickness on the inner surface of a graphite heat treatment container (hereinafter referred to as a container) 1 shown in Table 1 are used. ~ 7 were produced. The Cr ingot for coating the surface of the heat treatment container has a diameter of 60 mm, a length of 100 mm, and a gas content of 30 ppm or less, which is obtained by an arc melting method.

[0033]

[Table 1]

Here, the Cr molded body described above is used in various containers 1 to 1.
It was placed on No. 7 and heat-treated at 1250 ° C. in vacuum to obtain a Cr sintered body. With respect to this Cr sintered body, the surface damage state when taken out from the heat treatment container and the contamination state due to impurities were evaluated, and the results are shown in Table 2.

[0035]

[Table 2]

Using the Cr sintered body thus obtained as a Cr target for sputtering, 300 minutes (5 hours) of continuous time sputtering was sequentially performed on eight substrates for 2.0 μm with respect to a substrate having a diameter of 42 mm. A coating film having a thickness of 1 was prepared, and differences in film thickness variation among the substrates were compared. (Examples 1 to 4)

The coatings obtained using the targets of Examples 1 to 4 had a value of 2% or less. In addition, the variation in the film thickness distribution depending on the location on one sheet was not more than 1%, and the impurities were small. Further, the oxygen gas in the film is further reduced in gas by the synergistic effect of the gettering action of Cr on the surface of the heat treatment container and the reducing action of carbon, which is the material for the heat treatment container. (Examples 1 to 4 in Table 2 used the heat treatment vessels 3 to 6 in Table 1.
Example 1 corresponds to the container 3 and Example 2 corresponds to the container 4). (Comparative Examples 1 to 3)

On the other hand, the coating films obtained by using the targets of Comparative Examples 1 to 3 had variations in the range of 2 to 6%. Moreover, not only the variation of the film thickness distribution depending on the place in one sheet was 1 to 3%, but also the impurities were Pb and the presence of impurities such as trace trace non-volatile components in graphite and chromium carbide. The non-uniformity of the film thickness was observed due to the non-uniformity of the sputtering rate due to the presence of.
Further, with respect to the amount of oxygen gas in the coating, only the reducing action of carbon in the container 1 was carried out, but the amount of Cr on the surface of the container for heat treatment was not sufficient in the container for heat treatment 2, therefore
The getter action of is not exhibited. (Comparative Examples 1 and 2 in Table 2 use the containers 1 and 2 for treatment in Table 1 and Comparative Example 3
Uses the heat treatment container 7. Comparative Example 1 corresponds to Container 1, Comparative Example 2 corresponds to Container 2).

Further, the characteristics of the Cr sintered body thus obtained were used as a consumable electrode for vapor deposition plating, and the characteristics were compared. As a result, the electrodes according to Examples 1 to 4 showed little abnormal wear and had a long life. In addition, the film thickness distribution of vapor deposition plating was uniform and the amount of impurities was small.

Thickness used as a component for electronic equipment
When heat-treating a 0.8 mm high-purity Cr plate having a purity of 99.99% at 580 ° C., when the container 4 was used, it could be taken out from the container without surface damage and the subsequent fine workability was good. It was This is because the malleability of high-purity Cr was not impaired, and high-purity Cr was not generated during the heat treatment.
This is because impurities entered the plate and the amount of attached gas was small. When the container 1 was used at the same time, it could not be taken out from the container without surface damage, which hindered the subsequent fine processing workability. This is because the malleability of high-purity Cr has been impaired.
It is caused by the invasion of impurities and the attached gas.

In the heat treatment of component materials which particularly require workability for fine processing as in this embodiment, when chromium oxide is used for a part or all of the surface layer of the container 4, surface damage when taken out from the container is further increased. It is advantageous because it can be small and mild.

As described above, it was found that the plants and systems employing the targets, the consumable electrodes and the like manufactured by using the heat treatment containers as shown in Examples 1 to 4 can suppress the variation in performance. (Examples 5-6, Comparative Examples 4-5)

In the above-mentioned Examples 1 to 4, the example of the container in which the surface of the heat treatment container used for the heat treatment was coated with Cr having a predetermined thickness was described, but in the present invention, the material of the heat treatment container is carbon. In obtaining a synergistic effect of the reducing action of and the getter action of Cr on the surface of the heat treatment container,
Zr is also effective in addition to Ti described above.

The above experiments (3) and (4) were carried out using the heat treatment container 8 (Examples 5 to 6). Experiments (5) and (6) were carried out using the heat treatment vessels 9 to 10 (Comparative Examples 4 to 5). Also, like the heat treatment container 11, Zr
The same effect was obtained by coating.

[0045]

As described above, according to the present invention, the surface of the accommodating means for accommodating the member is coated with chromium, titanium or zirconium, and at least a part of the coated member is made of its oxide. It is possible to provide a highly reliable container for heat-treating a member that can obtain a high-quality member after heat treatment.

Claims (2)

[Claims] 1. A container for heat treatment of a member, characterized in that the surface of a housing means for housing the member is coated with chromium, titanium or zirconium, and at least a part of the coated member is an oxide thereof. 2. The coating member with which the surface of the accommodating means is coated has a thickness of 0.1 to 60 μm.
The container for heat treatment of the member as described.