A negative wear ultra-wear current carrying friction pair material

Abstract

The present application relates to a kind of negative wear's super wear-resistant current-carrying friction pair material, the current-carrying friction pair material is in situ constructed and exists stably under the electrically conductive lubricating film of current-carrying friction condition, is made of Ga-based liquid metal, Mo coating and Al alloy stake.The present application utilizes the cooperation between friction pair materials, adjusts the electrically conductive lubricating film generated by friction interface reaction, has excellent lubrication and wear resistance performance;In larger voltage and current range, average friction coefficient is always maintained at 0.25 below, the existence of lubricating film makes surface present negative wear, average negative wear rate is 1.28 × 10 ‑6 mm 3 / Nm above.The obtained material is suitable for application in the field of electric contact industry and provides lubrication and wear protection for the surface of mechanical parts.

Description

Technical Field

[0001] This invention relates to the field of lubricating materials and near-zero wear technology, and in particular to an ultra-wear-resistant current-carrying friction pair material with negative wear. Background Technology

[0002] Current-carrying friction refers to the process of passing direct current (DC) voltages of 0-50 V and currents of 0-20 V through the friction contact surfaces during friction. Unlike traditional friction conditions, current-carrying friction pairs exhibit a coupled damage mechanism characterized by mechanical wear, corrosive wear, and arc erosion under the combined action of the mechanical friction system and the electrical contact system. Typically, arc erosion and Joule heat accumulation are prone to occur during current-carrying friction; therefore, the electrical contact interface requires high electron transport capacity and resistance to arc erosion wear. Developing a system that combines conductivity and lubrication properties is a key technology for developing high-performance current-carrying friction pairs.

[0003] The main technical challenge in achieving surface protection and low wear under current-carrying friction conditions is suppressing arc erosion and mechanical wear. Material surfaces suffer from severe wear, softening, oxidation, and ablation during current-carrying friction. Traditional current-carrying friction pairs are mainly designed with conductive soft metal materials and lubricating greases with poor conductivity. These materials suffer from poor mechanical properties under high load, high speed, and high temperature conditions, and arc breakdown of the organic lubricating film under high current conditions. This leads to continuous wear in the sliding contact area during friction, severely affecting the service life and stable operation of conductive contact components.

[0004] Chinese patent CN118516586A discloses a TiB2-reinforced Cu-based composite material, which exhibits good electrical conductivity and a low coefficient of friction, but its current-carrying and wear-resistant properties are poor. Chinese patents CN118085941A and CN119286571A disclose a lubricating oil-fatty amide and an amide-based conductive grease, respectively, which significantly reduce the coefficient of friction of the material; however, organic lubricating films still struggle to overcome their inherent problems of low melting point, low load-bearing capacity, and poor resistance to arc erosion. Chinese patents CN119811738A and CN119812812A utilize Ga-based liquid metals of different viscosities as conductive lubricating phases, achieving excellent electrical conductivity and lubrication properties on the friction contact surface; however, the wear rate of the abrasive materials under current-carrying friction conditions remains consistently high. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-performance, wear-resistant, current-carrying friction pair material with negative wear.

[0006] To solve the above problems, the present invention provides an ultra-wear-resistant current-carrying friction pair material with negative wear, characterized in that: the current-carrying friction pair material is a conductive lubricating film that exists stably under current-carrying friction conditions and is constructed in situ, consisting of Ga-based liquid metal, Mo coating and Al alloy plug.

[0007] The current-carrying friction pair material is mainly composed of Ga@Al nanoparticles with a core-shell coating structure.

[0008] The Mo coating is prepared by means of the following method: Mo powder is deposited onto the surface of a CuCrZr alloy substrate using explosive spraying technology, and then naturally cooled.

[0009] The conditions for explosive spraying are that the oxygen-fuel ratio is set to 1:1, the air volume is set to 60%, and the spraying distance is adjusted to 200 mm.

[0010] The Al alloy plug is prepared by processing 7075 aluminum alloy raw material into a cylinder with a length of 27 mm and a diameter of 6 mm, and a hemispherical end.

[0011] The method for preparing a negative wear-resistant, ultra-wear-resistant current-carrying friction pair material as described above is characterized by: first grinding and polishing the Mo coating, and then using H... + Impurities are removed using an HCl solution with an ion concentration of 0.1 mol / L. Then, Ga-based liquid metal is dropped onto the surface of the Mo coating. The positions of the Al alloy plug and the coating are adjusted until both surfaces are completely submerged in Ga-based liquid metal to obtain a conductive lubricating film.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. This invention combines the protective properties of Mo coating on the surface of mechanical parts with the conductive lubrication properties of liquid metal to create a conductive friction pair material that exhibits negative wear under current-carrying friction conditions.

[0014] 2. This invention constructs a conductive lubricating film in situ on the coating surface, enabling the current-carrying friction pair to possess excellent lubrication, wear resistance, high-temperature erosion resistance, and high conductivity, overcoming the design defects of traditional soft metals and conductive greases under current-carrying friction conditions.

[0015] 3. The ultra-wear-resistant current-carrying friction pair material described in this invention has excellent friction-reducing and wear-resistant effects. While ensuring current transmission efficiency, it achieves wear-free protection of the material surface and macroscopic negative wear by isolating the contact between the coating and the Al alloy pin.

[0016] 4. The excellent lubrication and wear resistance mechanism of the ultra-wear-resistant current-carrying friction pair material described in this invention comes from the fact that, under the action of current and friction, a wear-resistant lubricating film composed of Ga@Al nanoparticles with a core-shell coating structure will be rapidly formed on the surface of the Mo coating with Ga-based liquid metal.

[0017] 5. The Mo coating prepared by explosive spraying technology included in this invention has a dense structure and good mechanical and electrical properties, which provides strong support for negative wear and ultra-wear resistance under current-carrying friction conditions.

[0018] 6. The ultra-wear-resistant current-carrying friction pair material described in this invention exhibits excellent lubrication and anti-wear properties under high speed, heavy load, and high current voltage conditions. It displays excellent tribological properties over a wide current carrying range of 0-50 V and 0-20 A. The coefficient of friction remains consistently below 0.25; the coating surface experiences almost no wear, even exhibiting negative wear in the presence of a stable lubricating film.

[0019] 7. The ultra-wear-resistant current-carrying friction pair material described in this invention still achieves excellent conductivity and negative wear effect under high voltage (50 V) and current (20 A) levels, and the amount of negative wear increases with the increase of voltage and current within a certain range, thus enhancing the protective effect.

[0020] 8. The Ga-based liquid metal, Mo coating, and Al alloy plug selected in this invention are all commonly used materials in the fields of conductivity, wear resistance, and lubrication; the Mo coating preparation method is simple and rapid. At the same time, the system requires low manufacturing costs, making it suitable for applications in the electrical contact industry and providing lubrication and wear protection for the surfaces of mechanical parts.

[0021] 9. The use of the material described in this invention provides key technical reserves for the long service life of conductive materials under current-carrying conditions in the power and electronics fields and the reliability of mechanical equipment. Attached Figure Description

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] Figure 1 This is the cross-sectional morphology of the Mo coating of the present invention.

[0024] Figure 2 The average friction coefficient and wear rate of this invention vary with voltage.

[0025] Figure 3 The average friction coefficient and wear rate of this invention vary with current.

[0026] Figure 4 This is the cross-sectional morphology of the lubricating film of the present invention.

[0027] Figure 5 This is a magnified view of the Ga@Al nanoparticles inside the lubricating film of the present invention. Detailed Implementation

[0028] The negative wear described in this invention refers to the phenomenon where the material surface is almost unworn, but the wear amount is negative due to the formation of a lubricating film.

[0029] A novel wear-resistant, ultra-wear-resistant current-carrying friction pair material with negative wear characteristics is presented. This material is an in-situ constructed conductive lubricating film that is stable under current-carrying friction conditions, composed of Ga-based liquid metal, a Mo coating, and Al alloy plugs. The material is primarily composed of core-shell coated Ga@Al nanoparticles.

[0030] The Mo coating is prepared by depositing Mo powder onto the surface of a CuCrZr alloy substrate using explosive spraying technology, followed by natural cooling. The conditions for explosive spraying are an oxygen-fuel ratio of 1:1, an air filling rate of 60%, and a spraying distance of 200 mm.

[0031] Al alloy bolts are made by processing 7075 aluminum alloy raw materials into cylinders with a length of 27 mm and a diameter of 6 mm, and the ends of which are hemispherical.

[0032] The material obtained by this invention maintains a friction coefficient below 0.25 under different current-carrying and high-load high-speed friction conditions within the voltage range of 0 to 50 V and the current range of 0 to 20 A, and can achieve lubrication and negative wear performance under any current-carrying friction condition.

[0033] The preparation method of this ultra-wear-resistant current-carrying friction pair material is as follows: the Mo coating is first polished, and then H is used. + Impurities are removed using an HCl solution with an ion concentration of 0.1 mol / L. Then, Ga-based liquid metal is dropped onto the surface of the Mo coating. The positions of the Al alloy plug and the coating are adjusted until both surfaces are completely submerged in Ga-based liquid metal to obtain a conductive lubricating film.

[0034] Example

[0035] The current-carrying friction pair material consists of three parts: Ga-based liquid metal, a Mo coating, and Al alloy plugs. The material can construct a stable conductive lubricating film under current-carrying friction conditions in situ, mainly composed of core-shell coated Ga@Al nanoparticles. The Ga@Al nanoparticles primarily originate from the penetration of the Ga-based liquid metal into the Al alloy grain boundaries, the encapsulation of nanoparticles, and the reconstruction on the Mo coating surface.

[0036] Depend on Figure 4As can be seen, the coating surface is smooth and almost unworn. The lubricating film is approximately 1 μm thick and consists of Ga@Al nanoparticles, forming a relatively dense composite structure. Figure 5 It can be seen that the Ga@Al nanoparticles inside the lubricating film exhibit typical core-shell structure characteristics. The outer layer of Ga-based liquid metal mainly provides lubrication and electrical conductivity, while the inner nanoparticles mainly provide mechanical load-bearing properties.

[0037] Mo coating preparation: Mo powder was deposited onto the surface of a CuCrZr alloy substrate using explosive spraying technology. During spraying, the oxygen-fuel ratio was set to 1:1, the gas filling rate was set to 60%, and the spraying distance was adjusted to 200 mm. The Mo coating was obtained after natural cooling. As shown in Figure 1, the coating thickness is 310 μm, with a dense internal structure and good adhesion to the CuCrZr alloy substrate.

[0038] Preparation of Al alloy plug: The 7075 aluminum alloy raw material is processed into a cylinder with a length of 27 mm and a diameter of 6 mm, and the end is hemispherical.

[0039] [No current-carrying friction]

[0040] Al alloy plugs were used as the upper specimen, and Mo-coated samples were used as the lower specimen, all fixed on the test stage. Before use, all samples and Al alloy plugs were ultrasonically cleaned with acetone for 20 minutes and then dried in an oven at 80 °C for 1 hour.

[0041] Before the tribological test, contaminants and impurity oxides on the surface of the polished Mo-coated sample were removed using an HCl solution. After surface cleaning, 2g of Ga-based liquid metal was dropped onto the surface of the Mo-coated sample. The positions of the Al alloy pin and the coating were adjusted until both surfaces were completely submerged in the Ga-based liquid metal.

[0042] During the friction test, a normal stress of 30 N was applied, the reciprocating frequency of the test bench was 13 Hz, and the reciprocating length was 5 mm. When the surfaces began to contact and reached the predetermined load and reciprocating speed, the DC power supply was not connected, serving as a control group. The friction test was conducted at room temperature (25 ℃) for 30 minutes. The friction coefficient during the test was automatically recorded by a computer, and the average friction coefficient was calculated by software. A non-contact optical three-dimensional profilometer was used to measure the three-dimensional morphology and wear rate of the worn surfaces.

[0043] Test results: The average coefficient of friction was 0.22 ± 0.04, and the average negative wear rate was 1.79 ± 0.53 × 10⁻⁶. - 6 mm 3 / Nm.

[0044] [Voltage-carrying current-carrying friction]

[0045] Al alloy plugs were used as the upper specimen, and Mo-coated samples were used as the lower specimen, all fixed on the test stage. Before use, all samples and Al alloy plugs were ultrasonically cleaned with acetone for 20 minutes and then dried in an oven at 80 °C for 1 hour.

[0046] Before the tribological test, contaminants and impurity oxides on the surface of the polished Mo-coated sample were removed using an HCl solution. After surface cleaning, 2g of Ga-based liquid metal was dropped onto the surface of the Mo-coated sample. The positions of the Al alloy pin and the coating were adjusted until both surfaces were completely submerged in the Ga-based liquid metal.

[0047] During the friction test, a normal stress of 30 N was applied, the reciprocating frequency of the test bench was 13 Hz, and the reciprocating length was 5 mm. When the surfaces began to contact and reached the predetermined load and reciprocating speed, the DC power supply was turned on, allowing the set current to flow through the Al alloy pin and the coating contact surface, forming a closed loop in the friction system. Current-carrying conditions: a fixed current of 10 A, and voltage values ​​set to 10 V, 30 V, and 50 V, respectively. All friction tests were conducted at room temperature (25 ℃) for 30 minutes. The friction coefficient during the test was automatically recorded by a computer, and the average friction coefficient was calculated by software. The three-dimensional morphology and wear rate of the worn surface were measured using a non-contact optical three-dimensional profilometer.

[0048] The test results are shown in Table 1 and Figure 2 As shown.

[0049] Table 1. Friction coefficient and wear rate

[0050]

[0051] As the voltage increases to 30 V, the coefficient of friction decreases from 0.21 to 0.18; however, when the voltage reaches 50 V, the coefficient of friction actually increases to 0.24. Furthermore, as the voltage continues to increase, the accumulation of negative wear on the surface increases from 1.79 × 10⁻⁶. -6 mm 3 / Nm continuously increased to 3.40 × 10 -6 mm 3 / Nm.

[0052] [Frictional Current Carrying Friction]

[0053] Al alloy plugs were used as the upper specimen, and Mo-coated samples were used as the lower specimen, all fixed on the test stage. Before use, all samples and Al alloy plugs were ultrasonically cleaned with acetone for 20 minutes and then dried in an oven at 80 °C for 1 hour.

[0054] Before the tribological test, contaminants and impurity oxides on the surface of the polished Mo-coated sample were removed using an HCl solution. After surface cleaning, 2g of Ga-based liquid metal was dropped onto the surface of the Mo-coated sample. The positions of the Al alloy pin and the coating were adjusted until both surfaces were completely submerged in the Ga-based liquid metal.

[0055] During the friction test, a normal stress of 30 N was applied, the reciprocating frequency of the test bench was 13 Hz, and the reciprocating length was 5 mm. When the surfaces began to contact and reached the predetermined load and reciprocating speed, the DC power supply was turned on, allowing the set current to flow through the Al alloy pin and the coating contact surface, forming a closed loop in the friction system. Current-carrying conditions: a fixed voltage of 30 V, and current values ​​set to 5 A, 15 A, and 20 A, respectively. All friction tests were conducted at room temperature (25 ℃) for 30 minutes. The friction coefficient during the test was automatically recorded by the computer, and the average friction coefficient was calculated by software. The three-dimensional morphology and wear rate of the worn surface were measured using a non-contact optical three-dimensional profilometer.

[0056] The test results are shown in Table 2 and Figure 3 As shown.

[0057] Table 2. Friction coefficient and wear rate

[0058]

[0059] As the current increases from 5 A to 20 A, the average coefficient of friction remains between 0.15 and 0.20, with the lowest average coefficient of friction at 5 A. As the voltage increases, the accumulation of negative wear on the surface increases from 1.79 × 10⁻⁶. - 6 mm 3 / Nm increased to 2.73 × 10 -6 mm 3 / Nm. Both the coefficient of friction and negative wear show a trend of first increasing and then decreasing with increasing current.

[0060] It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A super wear-resistant current-carrying friction pair material with negative wear, characterized in that: This current-carrying friction pair material is an in-situ constructed conductive lubricating film that is stable under current-carrying friction conditions. It consists of Ga-based liquid metal, a Mo coating, and Al alloy plugs. The Mo coating is prepared by depositing Mo powder onto the surface of a CuCrZr alloy substrate using explosive spraying technology, followed by natural cooling. The preparation method of this current-carrying friction pair material involves first polishing the Mo coating, and then using H... + Impurities are removed using an HCl solution with an ion concentration of 0.1 mol / L. Then, Ga-based liquid metal is dropped onto the surface of the Mo coating. The positions of the Al alloy plug and the coating are adjusted until both surfaces are completely submerged in Ga-based liquid metal to obtain a conductive lubricating film.

2. The ultra-wear-resistant current-carrying friction pair material with negative wear as described in claim 1, characterized in that: The current-carrying friction pair material is mainly composed of Ga@Al nanoparticles with a core-shell coating structure.

3. The ultra-wear-resistant current-carrying friction pair material with negative wear as described in claim 1, characterized in that: The conditions for explosive spraying are that the oxygen-fuel ratio is set to 1:1, the air volume is set to 60%, and the spraying distance is adjusted to 200 mm.

4. The ultra-wear-resistant current-carrying friction pair material with negative wear as described in claim 1, characterized in that: The Al alloy plug is prepared by processing 7075 aluminum alloy raw material into a cylinder with a length of 27 mm and a diameter of 6 mm, and a hemispherical end.

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