Copper alloy surface high-conductivity high-wear-resistance coating and preparation method and application thereof

Abstract

The application discloses a high-conductivity and high-wear-resistance coating on a copper alloy surface and a preparation method and application thereof. The preparation method comprises the following steps: (1) depositing molybdenum powder on a copper alloy base body by a plasma spraying technology to obtain a first layer of porous molybdenum coating; (2) cleaning and drying the surface of the first layer of porous molybdenum coating, then melting and infiltrating copper infiltrating agents into the first layer of porous molybdenum coating by a plasma melting and infiltrating technology, and obtaining a first layer of copper-infiltrated coating through post-processing; (3) depositing molybdenum powder on the surface of the first layer of copper-infiltrated coating by the plasma spraying technology to obtain a second layer of porous molybdenum coating; and (4) cleaning and drying the surface of the second layer of porous molybdenum coating, then melting and infiltrating copper infiltrating agents into the second layer of porous molybdenum coating by the plasma melting and infiltrating technology, and obtaining a high-conductivity and high-wear-resistance coating on the surface of the copper alloy base body through post-processing. The coating formed by the application has high conductivity and high wear resistance, and effectively improves the load current friction and wear resistance of the copper alloy.

Description

Technical Field

[0001] This invention relates to the technical field of coating preparation, specifically to a highly conductive and wear-resistant coating for copper alloy surfaces, its preparation method, and its application. Background Technology

[0002] Copper and its alloys, due to their excellent electrical and thermal conductivity and resistance to electrical wear, are widely used in critical fields such as power transmission, electronics, and communications, ranging from various precision electronic components to large base station equipment. Especially in applications involving current-carrying friction pairs, such as the brushes and commutators of some motors, and the pantograph and contact wire of electric trains, copper and its alloys serve as key components, undertaking the dual functions of current transmission and mechanical contact. However, copper and its alloys are not without their limitations. In high-frequency, high-speed circuits with stringent material requirements, while copper and its alloys possess excellent conductivity, ensuring efficient signal transmission, their insufficient wear resistance becomes increasingly apparent. Due to prolonged exposure to frequent current surges and mechanical friction, the surface of copper and its alloys, as current-carrying friction pairs, is highly susceptible to wear. This not only severely affects their performance but also significantly shortens their service life, necessitating urgent improvement and enhancement.

[0003] To improve the wear resistance of copper alloys in current-carrying friction scenarios, preparing wear-resistant coatings on their surfaces is the mainstream technical approach. Chemical vapor deposition, electroplating, and cold spraying are commonly used coating preparation techniques in this field, and the resulting wear-resistant coating material systems are mostly iron-based alloys, nickel-based alloys, or composite coatings with added ceramic reinforcing phases. These coatings, due to their material properties and microstructure, can meet the core requirement of high wear resistance for current-carrying friction components. However, compared with the copper alloy substrate, iron-based, nickel-based, and ceramic-reinforced metal-based coatings have lower conductivity, which limits the applicability of wear-resistant coatings in current-carrying friction scenarios. Current-carrying friction components must resist mechanical wear and achieve stable current transmission during operation; if the coating only possesses excellent wear resistance, it cannot meet its comprehensive usage requirements. Therefore, the urgent technical challenge in the field of surface strengthening of copper alloy current-carrying friction pairs is to significantly improve its conductivity while ensuring high wear resistance, achieving a combined optimization of these two core properties. Therefore, to address the shortcomings of existing technologies, a preparation scheme for coatings that combine high conductivity and high wear resistance needs to be developed. Summary of the Invention

[0004] The purpose of this invention is to provide a highly conductive and wear-resistant coating for copper alloy surfaces, its preparation method, and its application. This invention employs plasma spraying technology, using molybdenum powder as the raw material, to prepare a coating with a porous structure. Molybdenum powder has high hardness and weak deformation ability during spraying, thus easily forming numerous pores between particles; especially when using crushed and agglomerated molybdenum powder, the powder itself contains a large number of pores, which can further increase the porosity of the coating. Subsequently, a copper infiltration agent is used to fill the pores of the coating, constructing multiple conductive channels within the coating and significantly improving its conductivity. The above "plasma spraying + copper infiltration" steps are repeated twice, ultimately obtaining a highly conductive and wear-resistant composite coating on the copper alloy surface. In the process of this invention, the porous molybdenum coating structure facilitates the formation of a continuous conductive network through copper infiltration, while the high hardness of the molybdenum coating ensures excellent wear resistance, giving the coating both good conductivity and wear resistance. Ultimately, this composite structure effectively improves the resistance of the copper alloy substrate to current-carrying friction and wear, enabling it to operate stably under high-friction and high-conductivity conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of this invention is to provide a method for preparing a highly conductive and wear-resistant coating on a copper alloy surface, comprising the following steps:

[0007] (1) Molybdenum powder is deposited on a copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer;

[0008] (2) The surface of the first porous molybdenum coating is cleaned and dried. Then, the copper infiltrator is infiltrated into the first porous molybdenum coating by plasma infiltration technology (so that the liquid copper infiltrator fills the pores of the first porous molybdenum coating). After post-treatment, the first copper infiltrated coating is obtained.

[0009] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrating coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrating coating.

[0010] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration technology to infiltrate the copper infiltrate agent into the second porous molybdenum coating (so that the liquid copper infiltrate agent fills the pores of the second porous molybdenum coating). After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate.

[0011] This invention employs plasma spraying technology to prepare a high-porosity molybdenum coating on a copper alloy substrate. The high porosity primarily stems from the following three factors: First, the process parameters selected during spraying are conducive to achieving high porosity. By controlling the high-energy plasma stream, the molybdenum powder is heated to a semi-molten state, laying the foundation for constructing a porous structure. Second, the molybdenum powder itself has high hardness and is not easily deformed after high-temperature, high-speed impact on the substrate, which facilitates pore formation. Third, this invention uses fragmented, agglomerated molybdenum powder, which is inherently rich in pore structure. Compared to dense, solid powder, it is easier to retain pores within the coating during deposition, thereby further enhancing the overall porosity.

[0012] Furthermore, the high hardness of molybdenum powder endows the coating with excellent hardness, laying the foundation for its outstanding wear resistance. Subsequently, the porous molybdenum coating surface obtained from each spraying is treated with a plasma infiltration method, melting and introducing a solid copper infiltrator into the pores. This process uses a plasma arc as a heat source, achieving selective infiltration through precise energy input control. As the liquid copper infiltrator uniformly fills the pores, a novel composite coating structure combining high conductivity and high wear resistance is constructed. In harsh frictional and wear environments, this coating exhibits superior performance: the inherent high hardness of the molybdenum coating effectively reduces wear loss caused by mechanical friction, significantly lowering the wear rate and thus greatly extending the overall service life of the coating. This allows related equipment to maintain stable operation for a longer period, significantly reducing maintenance costs.

[0013] The substrate of this invention is a clean copper alloy substrate. Specifically, the copper alloy substrate needs to be pretreated before use: the surface of the copper alloy substrate is ground with a grinding machine to remove the surface oxide layer and impurities, and to obtain a suitable surface roughness to facilitate coating adhesion. Then, the ground surface is cleaned with anhydrous ethanol to thoroughly remove oil and debris, ensuring that the surface is clean and dry, and finally a clean copper alloy substrate is obtained.

[0014] As a preferred embodiment, in step (1) or step (3),

[0015] The molybdenum powder has a particle size of 25~55μm and is a broken and agglomerated powder with pores between the powder particles.

[0016] The copper alloy matrix is ​​a chromium-zirconium copper matrix.

[0017] As a preferred embodiment, in the plasma spraying technology of step (1) or step (3),

[0018] The argon flow rate for plasma spraying is 50-60 L / min; and / or,

[0019] The hydrogen flow rate for plasma spraying is 7~9 L / min; and / or,

[0020] The current for plasma spraying is 350~420A; and / or,

[0021] The voltage for plasma spraying is 45~55V.

[0022] As a preferred embodiment, in the plasma spraying technology of step (1) or step (3),

[0023] The spraying distance for plasma spraying is controlled at 90~120mm; and / or,

[0024] The powder feed rate for plasma spraying is 30~40 g / min; and / or,

[0025] The spray gun moving speed for plasma spraying is 550~600mm / s.

[0026] Plasma spraying is a thermal spraying technology for strengthening and protecting material surfaces. A high-temperature plasma jet is generated by ionizing a working gas (such as argon or hydrogen) using a plasma spray gun. Molybdenum powder to be sprayed is fed into the plasma jet, rapidly heated to a semi-molten state, and then impacts the surface of a copper alloy substrate at extremely high speeds under the propulsion of the high-speed plasma jet. The molybdenum powder particles spread, flatten, and rapidly solidify on the copper alloy surface, accumulating layer by layer to ultimately form a coating with a certain thickness and porosity. This invention adjusts the process parameters in preparing the molybdenum coating using plasma spraying technology, appropriately increasing the argon flow rate, spraying distance, powder feed rate, and spray gun movement speed, while appropriately decreasing the hydrogen flow rate, current, and voltage. These parameters facilitate the formation of a porous coating structure.

[0027] In a preferred embodiment, in the plasma spraying of step (1) or step (3), the coating thickness formed by each spraying step is 18~25μm;

[0028] In step (1) or step (3), the porosity of the porous molybdenum coating formed in each step is independently 10%~15%; the pore size is about 0.1~4.5μm.

[0029] After the plasma spraying in steps (1) and (3) is completed, the total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 36~50μm.

[0030] As a preferred embodiment, in step (2) or step (4),

[0031] The copper penetration agent is a mixture of borax and pure copper powder (wherein borax is used as a penetration aid); the mass ratio of borax to pure copper powder is 1:5 to 1:10; the particle size of the pure copper powder is 10 to 25 μm; and the particle size of the borax is 5 to 15 μm.

[0032] As a preferred embodiment, in step (2) or step (4),

[0033] Plasma infiltration technology uses non-transfer arc plasma spraying equipment for copper infiltration treatment;

[0034] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5~5 L / min; argon is used as the ionizing gas with a flow rate of 3.5~4.5 L / min; the powder feeding gas flow rate is 5~6 L / min; the current is 90~120 A; the voltage is 28~30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 10~15 mm; the powder feeding rate is 6~10 g / min; and the scanning speed is 3.5~6.5 mm / s.

[0035] During plasma infiltration, a scanning speed of 3.5~6.5 mm / s allows sufficient time for the liquid copper infiltrator to melt and diffuse in. At the plasma infiltration scanning speed of this invention, the copper infiltrator can remain in a liquid state for a relatively long time. Borax mainly serves to reduce the surface tension of the copper liquid, and most of the borax floats on the surface of the molten pool as slag, which can be cleaned off through post-processing. Therefore, the main component of the copper infiltrated into the porous coating of this invention is copper, containing a small amount of borax.

[0036] In step (2) or step (4), the post-treatment is as follows: the residual borax slag on the surface is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0037] A second aspect of the present invention is to provide a highly conductive and wear-resistant coating on a copper alloy surface prepared by the method described in the first aspect of the present invention.

[0038] In a preferred embodiment, the wear rate of the coating is 3.6 × 10⁻⁶. -6 ~7×10 -6 mm 3 ·N -1 ·m -1 The preferred size is 4×10. -6 ~6.5×10 -6 mm 3 ·N -1 ·m -1 ;

[0039] The conductivity of the coating is 25%~35% IACS; preferably 27%~32% IACS.

[0040] The third aspect of the present invention is the application of the highly conductive and wear-resistant coating on the surface of copper alloy prepared by the method of the first aspect of the present invention in the fields of aerospace, rail transportation, new energy vehicles, and precision electronic equipment.

[0041] Highly conductive and wear-resistant coatings prepared on copper alloy substrates can be applied in multiple fields. In the aerospace field, for example, this coating can be applied to core components such as the copper alloy rails of electromagnetic catapult railguns. Under harsh conditions of high temperature, high current carrying capacity, high-speed friction, and electromagnetic shock, it can ensure that these copper alloy components maintain conductivity and wear resistance, effectively resisting surface damage caused by high-temperature oxidation and current-carrying friction wear, improving the component's anti-current friction life and structural stability and operational reliability under extreme service environments. In the rail transportation field, coating the surface of the copper conductor of the contact wire in the pantograph-catenary system with a highly conductive and wear-resistant coating can effectively reduce frictional loss between the pantograph carbon sliding plate and the copper conductor of the contact wire, extending the service life of the contact wire and pantograph carbon sliding plate assembly, while ensuring stable power transmission during high-speed train operation. In the field of new energy vehicles… This coating can be applied to core components such as the current-carrying friction pairs formed by the pins and sockets of copper alloy high-voltage connectors. Under conditions of high voltage, high current, frequent insertion and removal friction, and vibration, it can ensure that the current-carrying friction pairs maintain high conductivity and high wear resistance, effectively resist current-carrying friction wear, improve the service life of the components, and ensure the long-term reliability of the power supply system. In the field of precision electronic equipment, this coating can be applied to copper alloy core components such as precision motor brushes. Under harsh conditions of current-carrying friction and high-frequency micro-vibration, it can enable these copper alloy components to maintain high conductivity and high wear resistance, effectively resist surface damage caused by current-carrying friction wear, improve the component's resistance to current-carrying friction life and the conductivity transmission stability and long-term operational reliability in complex service environments.

[0042] Beneficial effects:

[0043] This invention addresses the current challenge of materials simultaneously possessing excellent electrical conductivity and wear resistance. By constructing a porous molybdenum coating and filling the pores within the coating with copper infiltration, it achieves a dual improvement in both wear resistance and electrical conductivity, effectively balancing both properties. Specifically, this is reflected in the following aspects:

[0044] In terms of performance, molybdenum powder itself has high hardness and exhibits low deformation tendency during plasma spraying, forming numerous pores. Especially when using fragmented, agglomerated molybdenum powder with many pores for coating preparation, a coating with high porosity can be obtained. Furthermore, the high hardness of molybdenum powder also endows the coating with good wear resistance. Subsequently, copper-infiltrating agents are used to fill the pores. This process of preparing a porous molybdenum coating and then infiltrating it with copper is repeated twice, ultimately forming multiple conductive channels within the coating to optimize its conductivity. The porous molybdenum coating and the multiple conductive channels formed within it work synergistically, enabling the coating to operate stably even in environments with high friction and stringent conductivity requirements. Taking the copper alloy contacts of on-load tap changers in the power transmission field as an example, this coating ensures stable current transmission during voltage regulation and effectively resists current-carrying frictional wear caused by frequent sliding, improving the contact's anti-electro-wear life and ensuring reliable operation under harsh conditions. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of copper infiltration treatment performed on the porous molybdenum coating formed after plasma spraying in Embodiment 1 of the present invention.

[0046] Figure 2 Here is a SEM image of the molybdenum powder used in an embodiment of the present invention;

[0047] Figure 3 This is a particle size distribution diagram of the molybdenum powder used in an embodiment of the present invention.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1-Copper alloy substrate, 2-First porous molybdenum coating, 3-Second porous molybdenum coating, 3-1-Porosity in the second porous molybdenum coating, 4-Borax, 5-Pure copper powder, 6-Plasma arc, 7-Copper penetrating into the porous coating. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] The chromium-zirconium-copper alloy substrates used in the following embodiments and comparative examples of the present invention require pretreatment before use: the surface of the copper alloy substrate is ground with a grinding machine to remove the surface oxide layer and impurities, and to obtain a suitable surface roughness to facilitate coating adhesion. Then, the ground surface is cleaned with anhydrous ethanol to thoroughly remove oil and debris, ensuring that the surface is clean and dry, and finally a clean chromium-zirconium-copper alloy substrate is obtained.

[0052] The copper alloy matrix used in the following embodiments and comparative examples of the present invention is a chromium-zirconium copper matrix.

[0053] The molybdenum powder used in the following embodiments of the present invention has a particle size of 25~55μm; it was purchased from Beijing Sansprue New Materials Co., Ltd.; it is a molybdenum powder formed by crushing and agglomeration, and has a certain porosity. Its morphology and particle size distribution are as follows: Figure 2 and Figure 3 As shown.

[0054] Example 1

[0055] A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface includes the following steps:

[0056] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; wherein, the plasma spraying process is as follows: plasma spraying equipment is used, and the argon flow rate is set to 55L / min, the hydrogen flow rate is set to 8L / min, the current is 390A, and the voltage is 50V.

[0057] Spraying operation: The spraying distance is controlled at 100mm, the powder feed rate is 35g / min, and the spray gun moving speed for plasma spraying is 570mm / s. The thickness of the first porous molybdenum coating formed by plasma spraying is controlled at 20~23μm, the porosity is 12.6%, and the pore size is approximately 0.2~4μm.

[0058] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltrator is infiltrated into the first porous molybdenum coating by plasma infiltration technology (so that the liquid copper infiltrator fills the pores of the first porous molybdenum coating). After post-treatment, the first copper infiltrated coating is obtained.

[0059] The copper penetration agent is prepared by weighing pure copper powder with a purity of 99.95% and borax, and mixing them evenly at a mass ratio of borax 4 (particle size 5~15μm) to pure copper powder 5 (particle size 10~25μm). Borax is used as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0060] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5 L / min; argon is used as the ionizing gas with a flow rate of 4 L / min; the powder feeding gas flow rate is 5.5 L / min; the current is 100 A; the voltage is 30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 12 mm; the powder feeding rate is 8 g / min; and the scanning speed is 5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0061] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0062] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 40~46μm.

[0063] (4) Clean and dry the surface of the second porous molybdenum coating, and then melt the copper infiltrator into the second porous molybdenum coating using plasma infiltration technology (so that the liquid copper infiltrator fills the pores of the second porous molybdenum coating). A schematic diagram of the plasma infiltration process is shown below. Figure 1 As shown; after post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate; here the copper infiltration agent, plasma infiltration parameters, and post-treatment are the same as in step (2).

[0064] Figure 1 The diagram shows that a first porous molybdenum coating 2 and a second porous molybdenum coating 3 are formed on the surface of the copper alloy substrate 1 by plasma spraying. The pores 3-1 in the second porous molybdenum coating are distributed in the molybdenum particle accumulation structure, which can provide channels for subsequent copper infiltration. The copper infiltration agent (a mixture of borax 4 and pure copper powder 5) is melted by the plasma arc 6. Under the action of capillary force, the copper liquid infiltrates into the pores of the coating. The copper 7 infiltrating into the porous coating (the main component of the copper 7 in the porous coating of the present invention is copper, containing a small amount of borax; at the plasma melting and infiltration scanning speed of the present invention, the copper infiltration agent can remain in a liquid state for a long time, and the borax mainly plays the role of reducing the surface tension of the copper liquid. Most of the borax floats on the surface of the molten pool in the form of slag, which can be cleaned off in post-processing; therefore, the main component of the copper 7 in the porous coating of the present invention is copper, containing a small amount of borax) forms a conductive channel through the coating, realizing a synergistic improvement in the coating's wear resistance and conductivity.

[0065] Example 2

[0066] A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface includes the following steps:

[0067] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; wherein, the plasma spraying process is as follows: plasma spraying equipment is used, and the argon flow rate is set to 50L / min, the hydrogen flow rate is set to 8L / min, the current is 420A, and the voltage is 54V.

[0068] Spraying operation: The spraying distance is controlled at 90 mm, the powder feed rate is 30 g / min, and the spray gun moving speed for plasma spraying is 550 mm / s. The thickness of the first porous molybdenum coating formed by plasma spraying is controlled to be 19~22 μm, the porosity is 11.2%, and the pore size is approximately 0.1~3.2 μm.

[0069] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0070] Preparation of copper penetration agent: Weigh out pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0071] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5 L / min; argon is used as the ionizing gas with a flow rate of 4 L / min; the powder feeding gas flow rate is 6 L / min; the current is 90 A; the voltage is 28 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 15 mm; the powder feeding rate is 10 g / min; and the scanning speed is 6.5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0072] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0073] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology to obtain the second porous molybdenum coating. The parameters of plasma spraying are the same as those in step (1), and the total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 38~44μm.

[0074] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0075] Example 3

[0076] A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface includes the following steps:

[0077] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; wherein, the plasma spraying process is as follows: plasma spraying equipment is used, and the argon flow rate is set to 52L / min, the hydrogen flow rate is 9L / min, the current is 400A, and the voltage is 52V.

[0078] Spraying operation: The spraying distance is controlled at 90 mm, the powder feed rate is 32 g / min, and the spray gun moving speed for plasma spraying is 560 mm / s. The thickness of the first porous molybdenum coating formed by plasma spraying is controlled at 21~23 μm, the porosity is 12.2%, and the pore size is approximately 0.2~3.8 μm.

[0079] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0080] Preparation of copper penetration agent: Weigh pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0081] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5 L / min; argon is also used as the ionizing gas with a flow rate of 4.5 L / min; the powder feeding gas flow rate is 5 L / min; the current is 100 A; the voltage is 29 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 14 mm; the powder feeding rate is 9 g / min; and the scanning speed is 5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0082] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0083] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 42~46μm.

[0084] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0085] Example 4

[0086] A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface includes the following steps:

[0087] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; wherein, the plasma spraying process is as follows: plasma spraying equipment is used, and the argon flow rate is set to 58L / min, the hydrogen flow rate is set to 7L / min, the current is 370A, and the voltage is 48V.

[0088] Spraying operation: The spraying distance was controlled at 110 mm, the powder feed rate at 37 g / min, and the spray gun moving speed for plasma spraying was 580 mm / s. The thickness of the first porous molybdenum coating formed by plasma spraying was controlled at 21~24 μm, with a porosity of 13.2% and a pore size of approximately 0.3~4.2 μm.

[0089] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0090] Preparation of copper penetration agent: Weigh out pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0091] Plasma infiltration uses argon as the protective gas with a flow rate of 5 L / min; argon is used as the ionizing gas with a flow rate of 4.5 L / min; the powder feeding gas flow rate is 5 L / min; the current is 110 A; the voltage is 29 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 12 mm; the powder feeding rate is 7 g / min; and the scanning speed is 4.5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0092] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0093] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 42~48μm.

[0094] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0095] Example 5

[0096] A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface includes the following steps:

[0097] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; Plasma spraying process: using plasma spraying equipment, the argon flow rate is set to 60L / min, the hydrogen flow rate is set to 7L / min, the current is 350A, and the voltage is 45V.

[0098] Spraying operation: Control the spraying distance to 120mm, the powder feed rate to 40g / min, and the plasma spraying gun moving speed to 600mm / s. Control the thickness of the first porous molybdenum coating formed by plasma spraying to be 22~25μm, the porosity to be 14.7%, and the pore size to be approximately 0.4~4.5μm.

[0099] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0100] Preparation of copper penetration agent: Weigh out pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0101] Plasma infiltration uses argon as the protective gas with a flow rate of 5 L / min; argon is used as the ionizing gas with a flow rate of 4.5 L / min; the powder feeding gas flow rate is 5 L / min; the current is 120 A; the voltage is 30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 10 mm; the powder feeding rate is 6 g / min; and the scanning speed is 3.5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0102] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0103] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 44~50μm.

[0104] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0105] Comparative Example 1

[0106] A method for preparing a copper alloy surface coating includes the following steps:

[0107] It adopts the same method as Example 1, except that the sprayed powder is 100% molybdenum solid powder. The solid powder used in Comparative Example 1 does not agglomerate, has excellent dispersion and flowability, and the powders do not agglomerate and have no agglomeration pores.

[0108] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer;

[0109] Plasma spraying process: Use plasma spraying equipment, set the argon flow rate to 55L / min, the hydrogen flow rate to 8L / min, the current to 390A, and the voltage to 50V.

[0110] Spraying operation: The spraying distance is controlled at 100mm, the powder feed rate is 35g / min, and the spray gun moving speed for plasma spraying is 570mm / s. The thickness of the first porous molybdenum coating formed by plasma spraying is controlled at 18~21μm, with a porosity of 7.2% and a pore size of approximately 0.1~1.5μm.

[0111] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0112] Preparation of copper penetration agent: Weigh out pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0113] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5 L / min; argon is used as the ionizing gas with a flow rate of 4 L / min; the powder feeding gas flow rate is 5.5 L / min; the current is 100 A; the voltage is 30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 12 mm; the powder feeding rate is 8 g / min; and the scanning speed is 5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0114] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0115] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 36~42μm.

[0116] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0117] Comparative Example 2

[0118] A method for preparing a copper alloy surface coating includes the following steps:

[0119] (1) Molybdenum powder is deposited on a clean chromium zirconium copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer;

[0120] Plasma spraying process: Using plasma spraying equipment, the argon flow rate is set to 67L / min, the hydrogen flow rate to 13L / min, the current to 440A, and the voltage to 62V.

[0121] Spraying operation: Control the spraying distance to 70mm, the powder feed rate to 20g / min, and the plasma spraying gun moving speed to 400mm / s. Control the thickness of the first porous molybdenum coating formed by plasma spraying to be 14~18μm, with a porosity of 4.9% and a pore size of approximately 0.1~0.8μm.

[0122] (2) The surface of the first porous molybdenum coating is cleaned and dried with anhydrous ethanol. Then, the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained.

[0123] Preparation of copper penetration agent: Weigh out pure copper powder with a purity of 99.95% and borax, and mix them evenly at a mass ratio of borax (particle size 5~15μm) to copper powder (particle size 10~25μm). Borax acts as a penetration aid to reduce the surface tension of copper and promote the penetration of copper liquid into the pores.

[0124] Plasma infiltration uses argon as the protective gas with a flow rate of 4.5 L / min; argon is used as the ionizing gas with a flow rate of 4 L / min; the powder feeding gas flow rate is 5.5 L / min; the current is 100 A; the voltage is 30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 12 mm; the powder feeding rate is 8 g / min; and the scanning speed is 5 mm / s. These parameters ensure that the solid copper infiltration agent is fully melted.

[0125] Post-treatment: The surface residue of borax slag is softened and dissolved by boiling water, then brushed off with a stiff brush, and finally ultrasonically cleaned with deionized water and dried.

[0126] (3) Molybdenum powder is deposited on the surface of the first copper-infiltrated coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrated coating. The parameters of plasma spraying are the same as those in step (1). The total thickness of the first porous molybdenum coating and the second porous molybdenum coating is 28~36μm.

[0127] (4) Clean and dry the surface of the second porous molybdenum coating, and then use plasma infiltration to infiltrate the copper infiltrate agent into the second porous molybdenum coating. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate. The parameters of the copper infiltrate agent, plasma infiltration, and post-treatment are the same as in step (2).

[0128] Comparative Example 3

[0129] A method for preparing a copper alloy surface coating includes the following steps:

[0130] It adopts the same method as Example 1, except that only steps (1) and (3) are performed, and the copper infiltration operations in steps (2) and (4) are not performed.

[0131] Comparative Example 4

[0132] A method for preparing a copper alloy surface coating includes the following steps:

[0133] It adopts the same method as Example 1, except that in the copper infiltration operation, the copper infiltration agent in steps (2) and (4) uses only pure copper powder and does not add borax.

[0134] The performance test results of the coatings prepared in the above embodiments and comparative examples are shown in Table 1.

[0135] Table 1

[0136] Comparative Example 1: Spraying with 100% solid molybdenum powder resulted in a decrease in coating porosity and an increase in coating density, leading to a slightly lower wear rate than in Example 1. However, the reduced porosity resulted in a decrease in copper penetration and a lack of conductive channels, with a conductivity of only 11.2% IACS, far lower than in Example 1. This demonstrates that breaking up agglomerated molybdenum powder can increase the porosity of plasma-sprayed coatings, thus achieving a balance between coating wear resistance and conductivity.

[0137] Comparative Example 2: Plasma spraying parameters for preparing low-porosity molybdenum coatings were selected, reducing the coating porosity to 4.9%. Lower porosity increases the coating hardness, and the wear rate decreases to 2.6 × 10⁻⁶. -6 mm3 ·N -1 ·m -1 The wear resistance is improved, but the conductivity decreases after copper infiltration, indicating that the preparation of this coating requires plasma spraying process parameters that are conducive to the formation of high porosity molybdenum coatings.

[0138] Comparative Example 3: Without copper infiltration treatment, the lack of copper-filled conductive channels resulted in a conductivity of only 5.1% IACS; simultaneously, the absence of copper-filled pores increased the coating's brittleness, leading to a wear rate of 5×10⁻⁶. -5 mm 3 ·N -1 ·m -1 This confirms the key role of copper infiltration in improving conductivity and wear resistance.

[0139] Comparative Example 4: In the copper diffusion process, the copper diffusion agent only diffuses into pure copper powder without adding borax. This fails to reduce the surface tension of the copper, thus hindering the penetration of molten copper into the pores. Consequently, the coating pore-filling effect is poor, and the wear rate eventually increases to 8.2 × 10⁻⁶. - 6 mm 3 ·N -1 ·m -1 The conductivity decreased to 12.9% IACS, confirming that borax, as a penetration aid, not only plays a key role in the plasma infiltration process of copper, but also effectively improves the conductivity and wear resistance of the coating.

[0140] Through the above specific embodiments, it can be seen that the present invention can stably prepare copper alloy surface coatings that have both high wear resistance and high conductivity, meeting the application requirements of current-carrying friction pairs in high-frequency, high-speed, and high-wear environments.

[0141] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a highly conductive and wear-resistant coating on a copper alloy surface, characterized in that, Includes the following steps: (1) Molybdenum powder is deposited on a copper alloy substrate by plasma spraying technology to obtain the first porous molybdenum coating layer; (2) The surface of the first porous molybdenum coating is cleaned and dried, and then the copper infiltration agent is infiltrated into the first porous molybdenum coating by plasma infiltration technology. After post-treatment, the first copper infiltrated coating is obtained. (3) Molybdenum powder is deposited on the surface of the first copper-infiltrating coating by plasma spraying technology, and a second porous molybdenum coating is obtained on the surface of the first copper-infiltrating coating. (4) The surface of the second porous molybdenum coating is cleaned and dried. Then, the copper infiltration agent is infiltrated into the second porous molybdenum coating by plasma infiltration technology. After post-treatment, a highly conductive and wear-resistant coating is obtained on the surface of the copper alloy substrate.

2. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In step (1) or step (3), The molybdenum powder has a particle size of 25~55μm, and the molybdenum powder is a broken and agglomerated powder with pores between the powder particles; and / or, The copper alloy matrix is ​​a chromium-zirconium copper matrix.

3. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In the plasma spraying technology of step (1) or step (3), The argon flow rate for plasma spraying is 50-60 L / min; and / or, The hydrogen flow rate for plasma spraying is 7~9 L / min; and / or, The current for plasma spraying is 350~420A; and / or, The voltage for plasma spraying is 45~55V.

4. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In the plasma spraying technology of step (1) or step (3), The spraying distance for plasma spraying is controlled at 90~120mm; and / or, Plasma spraying has a powder feed rate of 30~40 g / min; and / or, The spray gun moving speed for plasma spraying is 550~600mm / s.

5. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In the plasma spraying technology of step (1) or step (3), the coating thickness formed by each spraying step is 18~25μm.

6. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In step (2) or step (4), The copper infiltration agent is a mixture of borax and pure copper powder; the mass ratio of borax to pure copper powder is 1:5 to 1:10; the particle size of the pure copper powder is 10 to 25 μm; and the particle size of the borax is 5 to 15 μm.

7. The method for preparing a highly conductive and wear-resistant coating on a copper alloy surface according to claim 1, characterized in that: In step (2) or step (4), Plasma infiltration technology uses non-transfer arc plasma spraying equipment for copper infiltration treatment; Plasma infiltration uses argon as the protective gas with a flow rate of 4.5~5 L / min; argon is used as the ionizing gas with a flow rate of 3.5~4.5 L / min; the powder feeding gas flow rate is 5~6 L / min; the current is 90~120 A; the voltage is 28~30 V; the distance between the nozzle and the surface of the coating to be infiltrated is controlled at 10~15 mm; the powder feeding rate is 6~10 g / min; and the scanning speed is 3.5~6.5 mm / s.

8. A highly conductive and wear-resistant coating on a copper alloy surface prepared by the method according to any one of claims 1-7.

9. The high conductivity and high wear resistance coating on the copper alloy surface according to claim 8, characterized in that, The wear rate of the coating is 3.6 × 10⁻⁶. -6 ~7×10 -6 mm 3 ·N -1 ·m -1 ; The coating has a conductivity of 25%~35% IACS.

10. The application of a highly conductive and wear-resistant coating on a copper alloy surface prepared by the method according to any one of claims 1-7 in the fields of aerospace, rail transportation, new energy vehicles, and precision electronic equipment.

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