CN120041837A

CN120041837A - Method for reducing friction and abrasion by externally applied electric field, friction pair and marine equipment

Info

Publication number: CN120041837A
Application number: CN202510102897.7A
Authority: CN
Inventors: 韩天翼; 杨晔; 穆明洋; 张晨辉
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2025-01-22
Filing date: 2025-01-22
Publication date: 2025-05-27

Abstract

The present application relates to the field of mechanical friction technology, and provides a method, friction pair and marine equipment for reducing friction and wear by applying an external electric field. The method comprises: providing a friction pair consisting of a conductive part and an insulating part, and placing the friction area of the friction pair in a mixed aqueous solution, wherein the mixed aqueous solution comprises an electrolyte containing metal elements; applying a negative voltage to the conductive part to form an electric field between the conductive part and the insulating part, and when the friction pair is in operation, the cations of the electrolyte in the mixed aqueous solution are adsorbed on the surface of the conductive part to form a hydrated lubricating layer, and triboelectrochemical deposition occurs on the surface of the conductive part to form a triboelectrochemical deposition film, thereby reducing the friction coefficient and wear rate between the conductive part and the insulating part, and the material of the deposition film comprises metal oxides and metal hydroxides. The method of the present application can effectively reduce the friction coefficient and wear rate of the friction pair.

Description

Method for reducing friction and abrasion by externally applied electric field, friction pair and marine equipment

Technical Field

The application relates to the technical field of mechanical friction, in particular to a method for reducing friction and abrasion by an external electric field, a friction pair and marine equipment.

Background

Friction can cause loss of mechanical equipment and additional consumption of energy, wherein key moving parts of marine equipment, such as a propeller, a pump impeller, an anchor winch drum and the like, are soaked in seawater for a long time, and the smooth surface of the equipment becomes uneven due to corrosion of the material by the seawater, so that friction and abrasion are increased when the equipment is operated, and the energy consumption and the service life of the equipment are increased and shortened. Although marine environmental equipment can employ corrosion resistant materials, it is difficult to solve the frictional wear problem by only seawater lubrication. This is because the seawater has extremely low bearing capacity, and can only form a lubricating water film under high-speed operation, and under low-speed and heavy-load conditions. Seawater can be forced out of the contact area, resulting in high friction and high wear.

In the conventional art, a lubricant film is formed by applying a lubricant between surfaces rubbed against each other to avoid direct contact of the rubbed surfaces, and frictional resistance and material wear are reduced by constructing an interface layer having a high normal load-bearing capacity and as low a shear strength as possible. However, in the marine environment, the addition of lubricating oil is easily eliminated by the flushing of seawater, and therefore, the lubricating oil cannot be used in the seawater environment and pollutes the environment.

Disclosure of Invention

Based on this, it is necessary to provide a method, friction pair and marine apparatus for reducing friction and wear by an applied electric field, which effectively reduces the friction coefficient without adding lubricating oil.

In a first aspect, the present application provides a method of reducing friction and wear with an applied electric field, the method comprising:

Providing a friction pair consisting of a conductive piece and an insulating piece, and placing a friction area of the friction pair in a mixed aqueous solution, wherein the mixed aqueous solution comprises an electrolyte containing a metal element;

And applying negative voltage to the conductive piece to form an electric field between the conductive piece and the insulating piece, wherein when the friction pair operates, cations of the electrolyte in the mixed aqueous solution are adsorbed on the surface of the conductive piece to form a hydrated ion lubricating layer, triboelectrochemical deposition is carried out on the surface of the conductive piece to form a triboelectrochemical deposition film, the friction coefficient and the wear rate between the conductive piece and the insulating piece are reduced, and the material of the triboelectrochemical deposition film comprises a composite film consisting of metal oxides and metal hydroxides.

In some embodiments, the cations in the electrolyte include at least one of divalent metal ions and trivalent metal ions.

In some embodiments, the anions in the electrolyte include at least one of nitrate ions, sulfate ions, phosphate ions, and carbonate ions.

In some embodiments, the cations of the electrolyte include at least one of magnesium ions, cobalt ions, nickel ions, lanthanum ions, aluminum ions, and cerium ions.

In some embodiments, the molar concentration of the electrolyte in the mixed aqueous solution is 1mmol/L or more.

In some embodiments, the negative voltage applied to the conductive member is 2V or less and the current is 1mA or less.

In some embodiments, the material of the conductive member includes at least one of a metal material and a semiconductor material.

In some embodiments, the material of the insulator comprises at least one of a ceramic material and a polymeric material.

In some embodiments, the material of the conductive member comprises at least one of copper alloy, titanium alloy, steel, aluminum alloy, silicon, and silicon carbide.

In a second aspect, the application provides a friction pair, the friction pair comprises a conductive piece and an insulating piece which are oppositely arranged, a friction electrochemical deposition film is arranged on the surface of the conductive piece, which is in opposite friction contact with the insulating piece, and the friction electrochemical deposition film comprises a metal oxide and a metal hydroxide.

In some embodiments, the triboelectrochemical deposition film has a thickness of 3nm to 300nm.

In some embodiments, the crystals of the material of the triboelectrochemical deposition film satisfy an overall amorphous state, locally exhibiting a short-range ordered structure.

In some embodiments, the metal oxide includes at least one of lanthanum oxide, aluminum oxide, cerium oxide, cobalt oxide, magnesium oxide, and nickel oxide.

In some embodiments, the metal hydroxide comprises at least one of lanthanum hydroxide, aluminum hydroxide, cerium hydroxide, cobalt hydroxide, magnesium hydroxide, and nickel hydroxide.

In some embodiments, the friction pair further comprises a power supply, a negative electrode of the power supply being electrically connected to the conductive member, the power supply being configured to provide a negative voltage to the conductive member and to form an electric field between the conductive member and the insulating member.

In a third aspect, the application also provides a marine plant component comprising at least one of the friction pairs according to the second aspect.

Compared with the prior art, the application has at least the following beneficial effects:

The application utilizes cations in electrolyte aqueous solution to apply negative electricity to the conductive piece in the friction pair, under the action of an external negative electricity field, the cations form a hydration lubrication layer on the surface of the conductive piece through physical adsorption, and simultaneously form a friction electrochemical deposition film which is easy to shear through electrochemical deposition under the friction action, and the hydration lubrication layer and the friction electrochemical deposition film which is easy to shear are cooperated to reduce the friction coefficient of the friction pair and reduce abrasion. In addition, the application applies negative potential to the conductive member, which can play a role of cathodic protection and effectively slow down electrochemical corrosion in the seawater environment.

Drawings

FIG. 1 is a schematic diagram of an applied electric field provided in an embodiment of the present application for adsorbing ions on a surface of a conductive member to form a hydrated lubrication layer for reducing friction coefficient of a friction pair, wherein the conductive member is 10-conductive member, 11-triboelectrochemical deposition film, 20-insulating member;

FIG. 2 is a structural comparison of a conductive member forming a tribo-electrochemical deposited film according to one embodiment of the application;

FIG. 3 is a three-dimensional microscopic topography of a deposited film region on a conductive member provided in one embodiment of the present application;

FIG. 4 is a diagram showing a friction pair test structure provided in example 1 of the present application, wherein 10 a-a first copper alloy block, 20 a-ultra high molecular weight polyethylene balls;

FIG. 5 is a graph showing the results of the friction coefficient test at 180rpm for example 1 of the present application;

FIG. 6 is a graph showing the results of the friction coefficient test of example 1 according to the present application under different rotation speeds and applied voltages;

FIG. 7 is a cross-sectional transmission electron microscope image of the deposited film in example 1 of the present application;

FIG. 8 is a partial enlarged view of the deposited film in example 1 of the present application;

FIG. 9 is a diagram showing the structure of a friction pair test provided in example 2 of the present application, wherein 10 b-a second copper alloy block, 20 b-an ultra high molecular weight polyethylene ring;

FIG. 10 is a graph showing the results of the friction coefficient test in example 3 of the present application;

FIG. 11 is a graph showing the results of the friction coefficient test in example 4 of the present application;

FIG. 12 is a graph showing the results of the friction coefficient test in example 5 of the present application.

Detailed Description

The following detailed description of the present application will provide further details in order to make the above-mentioned objects, features and advantages of the present application more comprehensible. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, directly connected, indirectly connected through an intervening medium, or in communication between two elements or in an interaction relationship between two elements, unless otherwise explicitly specified. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In the conventional technology, the friction surface of the friction pair can also be subjected to surface modification, for example, the microstructure and chemical composition of the friction surface can be changed by electroplating, coating, ion implantation and other technologies, so as to reduce the surface friction coefficient. However, seawater has certain corrosiveness, and is easy to cause pitting corrosion of the friction pair, so that the service life of the friction pair is influenced. In addition, in the traditional technology, ionic liquid, surfactant and hydrated ions are utilized for electric control friction adjustment, namely, the arrangement state of the ionic liquid, the surfactant or the hydrated ions is changed by applying an electric field, so that the friction coefficient is adjusted, but the low-speed and heavy-load working conditions are still difficult to meet.

Based on this, the first aspect of the present application provides a method of reducing friction and wear by an applied electric field, the method of reducing friction and wear by an applied electric field comprising:

As shown in fig. 1, 2 and 3, a negative voltage is applied to the conductive member 10 to form an electric field between the conductive member 10 and the insulating member 20, and when the friction pair operates, cations of the electrolyte in the mixed aqueous solution are adsorbed on the surface of the conductive member 10 to form a hydrated ion lubrication layer, and triboelectrochemical deposition occurs on the surface of the conductive member 10 to form a triboelectrochemical deposition film 11, reducing the friction coefficient and wear rate between the conductive member 10 and the insulating member 20, and the material of the triboelectrochemical deposition film 11 includes metal oxides and metal hydroxides.

The friction surface of the friction pair is immersed in a mixed aqueous solution containing electrolyte, and metal cations are continuously adsorbed on the surface of a conductive member under the action of an external electric field to form a friction electrochemical deposition film. When the triboelectric chemical deposition film is damaged, adsorbed metal cations can be continuously and electrochemically deposited and supplemented on the triboelectric chemical deposition film for repairing, so that the balance between the consumption and the generation of the triboelectric chemical deposition film is realized, and the service life of a friction pair is effectively prolonged. And when the friction pair enters an ultra-low friction stage (friction coefficient < 0.02), the triboelectrochemical deposition film is substantially free from wear. The friction coefficient and friction loss of the friction pair are reduced by the cooperative cooperation of the friction electrochemical deposition film and the hydration lubricating layer formed by the external electric field.

The friction form and the contact form of the friction pair are not particularly limited and are not particularly limited. For example, the friction form of the friction pair may be rotary friction, reciprocating friction, or the like. The contact mode may be point contact or surface contact.

It is understood that the types of cations and anions in the electrolyte can be regulated and controlled according to actual needs, and the electrolyte can form a triboelectrochemical deposition film under the action of an external electric field and can be adsorbed to form a hydration lubrication layer.

In some embodiments, the cations in the electrolyte include at least one of magnesium ions, cobalt ions, nickel ions, lanthanum ions, aluminum ions, and cerium ions.

The application selects cations and anions in the electrolyte, can form a stable hydration lubrication layer and a triboelectrochemical deposition film on the surface of the conductive piece after negative potential is added, and can reduce corrosion to the surface of the conductive piece by adding negative potential, thereby effectively improving the lubrication effect and reducing the friction coefficient and the wear rate of the friction pair.

In some embodiments, the material of the electrolyte includes nitrate salts of lanthanum nitrate, nickel nitrate, cobalt nitrate, cerium nitrate, aluminum nitrate, magnesium nitrate, cobalt nitrate, and the like, and at least one of sulfate, phosphate, and carbonate of the corresponding cation.

It will be appreciated that the metallic elements in the metal oxides and metal hydroxides in the triboelectrochemical deposition films of the application correspond to the metallic elements in the electrolyte material. Wherein the metal element in the electrolyte may be a metal cation. For example, the metal element in the electrolyte is lanthanum, and then the metal oxide in the deposited film may be lanthanum oxide and the metal hydroxide may be lanthanum hydroxide.

In some embodiments, the molar concentration of the electrolyte in the mixed aqueous solution is 1mmol/L or more. Optionally 1mmol/L to 1mol/L. It is understood that the molar concentration of the electrolyte according to the present application refers to the sum of the molar concentrations of all electrolytes in the mixed aqueous solution, for example, lanthanum nitrate and nickel sulfate are included in the mixed aqueous solution, and the molar concentration of the electrolyte is the sum of the molar concentration of lanthanum nitrate and the molar concentration of nickel sulfate.

It will be appreciated that the aqueous mixture of the present application may also contain at least one of other water-soluble lubricants such as polyethylene glycol PEG, polyvinyl alcohol PVA, glycerol or ethylene glycol.

According to the application, the molar concentration of the electrolyte in the mixed aqueous solution is selected, so that on one hand, enough cations can be adsorbed on the surface of the conductive member to form a hydrated lubricating layer, and on the other hand, a stable triboelectrochemical deposition film can be formed on the surface of the conductive member, thereby improving the lubricating effect in a synergistic fit manner. If the molar concentration of the electrolyte is lower than 1mmol/L, the electrolyte is insufficient to adsorb enough ions, a hydration lubricating layer which can be effectively carried cannot be formed, and meanwhile, a longer time is required to participate in the triboelectrochemical reaction, so that a triboelectrochemical deposition film cannot be formed rapidly.

In some embodiments, the negative voltage applied to the conductive member is 2V or less. Optionally, the negative voltage ranges from-0.2V to-2V.

In some embodiments, the current applied to the conductive member is 1mA or less. Optionally, the current range is 1 μA-1 mA.

The application selects the voltage and the current applied to the conductive member as above, ensures that no obvious electrochemical reaction (such as no electrolytic water reaction and no bubble generation) is generated in the friction process, but the friction electrochemical deposition film is formed sufficiently, and simultaneously can better regulate the surface charge density of the conductive member so as to adsorb enough cations. If the voltage is relatively high, electrolytic water can be generated, oxidation corrosion of anode materials is accelerated, consumption of electrolyte aqueous solution is accelerated, mechanical properties of formed deposited films are poor, friction reduction and grinding are not facilitated, if the voltage is relatively low, surface charge density of conductive parts is low, cation adsorption quantity is small, a hydration lubricating layer cannot be formed or lubricating effect of the hydration lubricating layer is poor, and stable triboelectrochemical deposited films cannot be formed due to low voltage, and friction reduction and grinding are also not facilitated.

It will be appreciated that the conductive member of the present application may be a metallic material, such as an alloy material. Other materials capable of conducting electricity are also possible. In some embodiments, the material of the conductive member comprises at least one of a metal material and a semiconductor material, and may also be a silicon wafer, silicon carbide, gallium nitride, or other semiconductor material. For example, the material of the conductive member includes at least one of copper alloy, titanium alloy, steel, aluminum alloy, silicon, and silicon carbide.

In some embodiments, the material of the insulator comprises at least one of a ceramic material and a polymeric material. Alternatively, the insulator is surface negatively charged in the aqueous electrolyte solution, for example the polymer material may be PE (polyethylene), PTFE (polytetrafluoroethylene), PEEK (polyetheretherketone) or UHMWPE (ultra high molecular weight polyethylene). The surface of the insulating piece adopted by the application is negatively charged, so that the hydrated cations in the electrolyte aqueous solution can be adsorbed to form a hydrated lubrication layer, the lubrication effect is further improved, and the friction coefficient is reduced.

The method of applying the voltage to the conductive member may be selected according to actual needs, and the surface of the conductive member may be made to exhibit a negative potential, and may be powered by, for example, three-electrode (electrochemical workstation) or two-electrode (dc power supply).

In some embodiments, the pressure applied during operation of the friction pair is 0.1N-100N. Alternatively 1N, may be suitable for use at higher pressures.

Illustratively, there is provided a method for reducing the friction coefficient of a friction pair by the externally applied electric field, comprising:

providing a friction pair consisting of a conductive piece and an insulating piece, and placing a friction area of the friction pair in a mixed aqueous solution, wherein the mixed aqueous solution comprises an electrolyte containing a metal element, and the molar concentration of the electrolyte in the mixed aqueous solution is more than or equal to 1mmol/L;

And applying a negative voltage less than or equal to 2V to the conductive member and a current less than or equal to 1mA to form an electric field between the conductive member and the insulating member, wherein when the friction pair operates, cations of an electrolyte in the mixed aqueous solution are adsorbed on the surface of the conductive member to form a hydration lubricating layer, triboelectrochemical deposition is carried out on the surface of the conductive member to form a triboelectrochemical deposition film, the friction coefficient and the wear rate between the conductive member and the insulating member are reduced, and the triboelectrochemical deposition film comprises metal oxide and metal hydroxide.

In a second aspect, the application provides a friction pair, the friction pair comprises a conductive piece and an insulating piece which are oppositely arranged, a friction electrochemical deposition film is arranged on the surface of the conductive piece, which is in opposite friction contact with the insulating piece, and the material of the friction electrochemical deposition film comprises metal oxide and metal hydroxide.

According to the application, the friction coefficient and the wear rate of the friction pair can be reduced by arranging the friction electrochemical deposition film on the opposite friction contact surface of the friction pair.

In some embodiments, the crystals of the material of the rubbed electrochemically deposited film satisfy an overall amorphous state, locally exhibiting a short-range ordered structure. The deposited film of the application is wholly amorphous and has a local short-range order, and the deposited film of the structure has the characteristics of low shearing strength, small friction resistance and the like.

In some embodiments, the friction pair further comprises a power supply, a negative electrode of the power supply being electrically connected to the conductive member, the power supply being configured to provide a negative voltage to the conductive member and to form an electric field between the conductive member and the insulating member. It can be understood that the positive electrode of the power supply can be connected with the mixed liquid, so that the circuit conduction can be realized, and the occurrence of short circuit can be avoided.

In some embodiments, the opposing friction surfaces of the friction pair are immersed in a mixed aqueous solution containing an electrolyte. Alternatively, the positive electrode of the power supply may be electrically connected to the mixed aqueous solution. Taking marine equipment as an example, the friction pair can be directly immersed in seawater, and the negative electrode of the power supply is arranged near the conductive piece in the friction pair.

According to the friction pair, the power supply is arranged, so that the friction electrochemical deposition film in the friction pair is repaired in the operation process, and the hydrated cations in the mixed aqueous solution can be adsorbed on the surface of the conductive piece to cooperatively cooperate with the friction electrochemical deposition film, so that the lubrication effect is improved, and the service life of the friction pair is prolonged.

The third aspect of the application also provides a marine installation comprising a friction pair according to the second aspect. It is understood that marine installation refers to an installation that is immersed in a portion of sea water during operation. For example, it may be a propeller, pump impeller, or anchor capstan reel, etc.

Embodiments of the present application will be described in detail below with reference to examples. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application. The experimental methods in the following examples, in which specific conditions are not noted, are preferably referred to the guidelines given in the present application, and may be according to the experimental manual or conventional conditions in the art, the conditions suggested by the manufacturer, or the experimental methods known in the art.

The material of the insulator in the following examples was ultra high molecular weight polyethylene, UHMWPE ball product from vallisxing plastic materials limited in zhongshan. The conductive piece is a copper alloy block, and the model is ZCUSn10Zn2.

Example 1

A friction pair is provided wherein the insulator is an ultra high molecular weight polyethylene ball.

As shown in fig. 4, ultra-high molecular weight polyethylene balls 20a are loaded into an aluminum ball holder, a wire is wound on the aluminum ball holder, the aluminum ball holder is mounted on a sensor of a UMT frictional wear testing machine, and then a first copper alloy block 10a and an electric control friction device are fixed on a rotary table of the UMT frictional wear testing machine, and the negative electrode of a power supply is connected through a conductive adhesive and the wire. After the installation, the experimental parameters were set by the peripheral computer of the UMT frictional wear testing machine, namely, positive pressure of F _n =1N, rotation radius of 5mm, rotation speed of 180rpm, initial test time of 7min, and power output of 2V and 0.001A.

After the setting, 200. Mu.L of 1mol/L nickel nitrate aqueous solution is dripped into the contact position of the first copper alloy block 10a and the ultra-high molecular weight polyethylene ball 20a, at the moment, the power is not turned on, and the nickel nitrate aqueous solution can be contacted with the aluminum ball support.

The friction surface of the friction pair is in nickel nitrate aqueous solution, but the friction coefficient gradually stabilizes to about 0.06-0.08, as shown in fig. 5, although the friction surface is in nickel nitrate aqueous solution, as can be seen from the test of fig. 5, in which no voltage is applied, the friction surface is lubricated only by nickel nitrate aqueous solution, and no obvious lubrication effect can be achieved. After the friction coefficient is stable, the power supply is started to work, and the friction coefficient on a peripheral computer of the UMT friction and wear testing machine can be found to respond quickly, the friction coefficient starts to decrease quickly at the power-on moment, and the minimum friction coefficient after the friction coefficient is stable can reach 0.01-0.02. As shown in fig. 6, the friction pairs were tested at rotation speeds of 180rpm, 120rpm, 60rpm, 36rpm, 12rpm, 3rpm and 1rpm, respectively, under the conditions of-2V voltage, 0V voltage and +2v voltage applied to the conductive members in the friction pairs, respectively, and each of the conditions was tested two to three times, respectively. It can be seen that the friction coefficient can be reduced at various rotation speeds by applying negative voltage, and the friction coefficient is increased to about 0.06-0.07 at various speeds when no voltage is applied, and is increased to more than 0.08 when positive voltage is applied. Therefore, when the friction surface of the friction pair is immersed in the lanthanum nitrate aqueous solution, the friction coefficient of the friction pair can be effectively reduced by applying negative electricity to the conductive member, and meanwhile, the surface of the conductive member is almost free from abrasion and the surface abrasion of the insulating member is correspondingly reduced.

Further, the contact area of the copper alloy block after the experiment is subjected to Focused Ion Beam (FIB) cutting, the cutting surface is the section where the friction contact area is located, and a transmission electron microscope image shown in fig. 7 is obtained, and as can be seen, the lower right corner of the image is the copper alloy block, and other positions are the friction electrochemical deposition films. Under the transmission electron microscope, the crystals are regularly and orderly arranged, such as the lattice arrangement of copper alloy in the figure, but the non-crystals are in a disordered state, and locally present a short-range ordered structure, as shown in fig. 8, the distance between two transverse lines refers to the lattice spacing of the short-range ordered structure, and is 0.317nm. The deposited film can effectively reduce the friction coefficient of the friction pair because after the deposited film is formed, the friction shearing interface is transferred from a copper alloy/ultra-high molecular weight polyethylene interface to a deposited film/ultra-high molecular weight polyethylene interface, and the former has lower interface shearing resistance, so that the friction coefficient is lower.

Example 2

A friction pair was provided in which the insulator was an ultra-high molecular weight polyethylene ring with an outer diameter of 49.21mm.

As shown in fig. 9, a second copper alloy block 10b is fixed to the ring block friction tester, one electrode of a direct current power supply is connected to the second copper alloy block 10b, and the other electrode of the power supply is used as a counter electrode. The experiment set the applied voltage of-2V, the friction speed of 300rpm, the applied pressure of 10N, the lubricating medium of lanthanum nitrate aqueous solution, and the concentration of 1mol/L. The testing machine was started, the high molecular weight polyethylene ring 20b was brought into contact with the second copper alloy block 10b, and the high molecular weight polyethylene ring 20b and the second copper alloy block 10b were immersed in an aqueous lanthanum nitrate solution, and the counter electrode was connected to an aluminum block fixed in the aqueous lanthanum nitrate solution. When the friction coefficient is stabilized at about 0.1, the power supply is started, and the friction coefficient of a friction pair is reduced by more than 90% after the power supply is stabilized at about 0.01.

Example 3

The friction coefficient was reduced in the same manner as in example 1, except that the concentration of lanthanum nitrate solution was replaced with 0.5mmol/L, the rotation speed was 180rpm, no voltage was applied to the conductive member for 0s to 200s during the test, and a voltage of-2V was applied to the conductive member after 200s, and the friction coefficient test result was about 0.07 for the friction pair after stabilization, as shown in FIG. 10.

Compared with the embodiment 1, the embodiment 3 shows that the concentration of the electrolyte material in the mixed solution is controlled, so that enough cations are ensured to be adsorbed on the surface of the conductive member to form a hydration lubricating layer, and meanwhile, the easily-sheared deposition film can be ensured to be stably formed, and the problems that the friction coefficient is difficult to reduce and the like caused by direct contact between rough peaks of friction pairs can be avoided.

Example 4

The friction coefficient was reduced in the same manner as in example 1, except that the rotation speed was 180rpm, no voltage was applied to the conductive member for 0 to 200 seconds during the test, a voltage of-3V was applied to the conductive member after 200 seconds, and the friction coefficient test result was about 0.07 for the friction pair after stabilization, as shown in fig. 11.

Compared with the embodiment 1, the embodiment 4 can be seen that the application can avoid the occurrence of severe electrochemical reactions such as electrolysis of water and even generation of bubbles and the like and avoid the occurrence of problems such as increase of friction coefficient and the like caused by the electrochemical reactions on the premise of ensuring that the surface of the conductive piece physically adsorbs enough ions by controlling the applied voltage.

Example 5

The friction coefficient was reduced in the same manner as in example 1, except that in the test, a voltage of-2V was applied to the conductive member at a rotational speed of 180rpm for 0 to 500s, and the voltage was stopped after 500s, and the friction coefficient was gradually increased to about 0.05 as shown in FIG. 12.

Compared with the embodiment 1, the embodiment 5 shows that negative electricity is applied to the conductive piece in the running process of the friction pair, so that the continuous formation of a deposited film and the continuous existence of a hydration lubricating layer can be effectively ensured, and the problems of high friction coefficient caused by loss of the deposited film and failure of the hydration lubricating layer are avoided.

In summary, the electrolyte material containing metal elements in the mixed solution is utilized to apply negative electricity to the conductive member in the friction pair, cations in the electrolyte material are physically adsorbed on the surface of the conductive member to form a hydration lubrication layer under the action of an external electric field, and are electrochemically deposited to form a deposition film under the action of friction, so that the friction coefficient of the friction pair is reduced and the abrasion is reduced by the cooperation of the electrolyte material and the electrolyte material. In addition, the application applies negative potential to the conductive member, which can play a role in cathodic protection and effectively reduce electrochemical corrosion of seawater.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. The scope of the application should therefore be determined from the appended claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. A method for reducing friction and wear by applying an external electric field, characterized in that the method for reducing friction and wear by applying an external electric field comprises:

Providing a friction pair consisting of a conductive member and an insulating member, and placing a friction region of the friction pair in a mixed aqueous solution, wherein the mixed aqueous solution includes an electrolyte containing a metal element;

A negative voltage is applied to the conductive part to form an electric field between the conductive part and the insulating part. When the friction pair is in operation, cations of the electrolyte in the mixed aqueous solution are adsorbed on the surface of the conductive part to form a hydrated ion lubrication layer, and triboelectrochemical deposition occurs on the surface of the conductive part to form a triboelectrochemical deposition film, thereby reducing the friction coefficient and wear rate between the conductive part and the insulating part. The material of the triboelectrochemical deposition film includes metal oxides and metal hydroxides.

2. The method for reducing friction and wear by applying an external electric field according to claim 1, wherein the electrolyte satisfies at least one of the following conditions:

(1) The cations in the electrolyte include at least one of divalent metal ions and trivalent metal ions;

(2) The anions in the electrolyte include at least one of nitrate ions, sulfate ions, phosphate ions and carbonate ions.

3. The method for reducing friction and wear by applying an external electric field as described in claim 1 is characterized in that the cations in the electrolyte include at least one of magnesium ions, cobalt ions, nickel ions, lanthanum ions, aluminum ions and cerium ions.

4. The method for reducing friction and wear by applying an external electric field according to claim 1, wherein the method satisfies at least one of the following conditions:

(1) The molar concentration of the electrolyte in the mixed aqueous solution is greater than or equal to 1 mmol/L;

(2) The negative voltage applied to the conductive member is less than or equal to 2 V, and the current is less than or equal to 1 mA.

5. The method for reducing friction and wear by applying an external electric field according to any one of claims 1 to 4, characterized in that the friction pair satisfies at least one of the following conditions:

(1) The material of the conductive element includes at least one of a metal material and a semiconductor material;

(2) The material of the insulating member includes at least one of a ceramic material and a polymer material.

6. The method for reducing friction and wear by applying an external electric field as described in any one of claims 1 to 4, characterized in that the material of the conductive part includes at least one of copper alloy, titanium alloy, steel, aluminum alloy, silicon and silicon carbide.

7. A friction pair, characterized in that the friction pair comprises a conductive part and an insulating part arranged opposite to each other, and a friction electrochemical deposition film is provided on the surface of the conductive part and the insulating part in relative friction contact, and the material of the friction electrochemical deposition film comprises metal oxide and metal hydroxide.

8. The friction pair according to claim 7, characterized in that the triboelectrochemically deposited film satisfies at least one of the following conditions:

(1) The thickness of the triboelectrochemically deposited film is 3 nm to 300 nm;

(2) The material crystals of the triboelectrochemically deposited film satisfy the following requirements: overall amorphous morphology and local short-range ordered structure;

(3) The metal oxide includes at least one of lanthanum oxide, aluminum oxide, cerium oxide, cobalt oxide, magnesium oxide and nickel oxide;

(4) The metal hydroxide includes at least one of lanthanum hydroxide, aluminum hydroxide, cerium hydroxide, cobalt hydroxide, magnesium hydroxide and nickel hydroxide.

9. The friction pair as described in claim 7 or 8 is characterized in that the friction pair also includes a power supply, a negative pole of the power supply is electrically connected to the conductive member, and the power supply is used to provide a negative voltage to the conductive member and form an electric field between the conductive member and the insulating member.

10. A marine equipment, characterized in that the marine equipment comprises the friction pair described in any one of claims 7 to 9.