Coating material of high-strength beryllium copper bar and preparation method of coating material

Abstract

The invention relates to the technical field of coating materials, in particular to an electrodeposition Ni-Co-MoS2 composite coating, an in-situ growth nanocrystalline Ni-Al transition layer and a plasma spraying composite coating which are sequentially formed on the surface of a base body. According to the method, the Ni-Co-MoS2 composite coating, the in-situ growth nanocrystalline Ni-Al transition layer and the plasma spraying composite coating are sequentially electrically deposited on the surface of the beryllium copper bar, so that the performance of the coating is greatly improved, and the service life of the coating is prolonged. According to the method, the surface treatment of the base material comprises the steps of removing greasy dirt through alkali washing and etching the oxide layer through acid washing, so that the oxygen content of the surface of the base body is reduced, and a high-energy adsorption interface is provided for an electro-deposition layer. Through micro-arc oxidation and laser etching treatment, the porous membrane formed by micro-arc oxidation provides mechanical locking sites, and-OH groups on the surface of the porous membrane and Ni < 2 + > in an electrodeposition layer can form hydrogen bonds to enhance chemical bonding.

Description

Technical Field

[0001] The invention relates to the technical field of coating materials, in particular to a coating material for a high-strength beryllium copper rod and a preparation method thereof. Background Art

[0002] Beryllium copper rod is a non-ferrous metal alloy with excellent comprehensive performance. It is mainly composed of beryllium and copper. It has high strength, high hardness, good electrical conductivity, thermal conductivity and fatigue resistance. It is widely used in high-end fields such as aerospace, electronic communications, and precision machinery.

[0003] Beryllium copper rods are often used as key structural components or functional elements in electronic connectors, mold manufacturing, marine engineering, and other applications. However, in actual applications, the surface of beryllium copper rods is prone to scratches and wear due to factors such as friction, impact, or corrosion. This not only affects the appearance quality of the components but can also lead to performance degradation or even failure, seriously restricting its application in high-load and high-wear conditions.

[0004] In order to solve the problem of wear resistance and corrosion resistance of beryllium copper rod surface, existing technologies often use spraying and other processes to prepare protective coatings on its surface. However, the traditional coating system has obvious defects: on the one hand, the bonding strength between a single coating and the substrate is insufficient, and it is easy to peel off under alternating loads or friction; on the other hand, the hardness and wear resistance of the coating itself are relatively weak, and it cannot effectively resist external mechanical damage. Although conventional spray coatings can provide a certain degree of protection, due to the lack of effective connection of the transition layer, the interface bonding strength between the coating and the substrate is low; and although the electro-deposited coatings used in some existing technologies are tightly bonded to the substrate, the wear-resistant particles are unevenly distributed, resulting in limited overall wear resistance.

[0005] Therefore, developing a coating material with high bonding strength, high hardness and excellent wear resistance has become the key to improving the application performance of beryllium copper rods. Summary of the Invention

[0006] The purpose of the present invention is to provide a coating material for high-strength beryllium copper rods. The purpose of the present invention is to develop a coating material with high bonding strength, high hardness and excellent wear resistance.

[0007] To achieve the above object, the present invention provides the following technical solutions: A coating material for high-strength beryllium copper rods, comprising an electrodeposited Ni-Co-MoS2 composite coating, an in-situ grown nanocrystalline Ni-Al transition layer, and a plasma sprayed composite coating sequentially formed on the surface of a substrate; The thickness of the electrodeposited Ni-Co-MoS2 composite coating is 10-15 μm, the thickness of the in-situ grown nanocrystalline Ni-Al transition layer is ≤5 μm, and the thickness of the plasma sprayed composite coating is 30-40 μm.

[0008] Preferably, the substrate is a beryllium copper rod.

[0009] Preferably, the in-situ grown nanocrystalline Ni-Al transition layer is prepared by heating to 500-550°C in an Ar atmosphere, keeping the temperature for 10-15 minutes, introducing an Ar-H2 mixed gas with a H2 volume fraction of 4%-6%, and evaporating Ni-Al alloy powder at a rate of 4-6 mL / min. The Ni:Al atomic ratio in the Ni-Al alloy powder is 3:1-1.4, and the particle size is ≤10μm.

[0010] Preferably, the spray coating of the plasma spray composite coating comprises, by mass ratio, 22%-30% of TiO2 powder, 15%-20% of SiO2 powder, 7%-10% of intercalation modifier, and the balance of Al2O3 powder; The average particle size is 10-15μm.

[0011] Preferably, the intercalation modifier is prepared by the following process: Mix 1-2 g of graphite powder with 0.5-0.8 g of NaNO3, add 60-90 mL of 98% concentrated sulfuric acid, stir in an ice bath, add 3-4 g of KMnO4 in 5 portions, control the reaction temperature to ≤10°C and react for 2 hours; heat to 35-38°C and continue to react for 30-40 minutes, slowly add 150-180 mL of deionized water, heat to 95°C and react for 15-18 minutes; add 5-7 mL of 30% hydrogen peroxide to terminate the reaction, filter, wash to neutrality and dry to obtain graphene oxide; The graphene oxide prepared above was ultrasonically dispersed in 100-110 mL of anhydrous ethanol, 2-3 mL of ethyl orthosilicate was added, and the mixture was stirred for 24-26 hours and then dried at 80° C. to prepare a SiO2 / graphene oxide composite material; The SiO2 / graphene oxide composite material was placed in a mixed gas atmosphere of 5% H2 and 95% Ar, and reduced at 800°C for 2-3h to obtain graphene-loaded nano-SiO2. Polytitanium silazane is added to the graphene-supported nano-SiO2, with the mass of the polytitanium silazane being 8%-10% of the mass of the graphene-supported nano-SiO2. After being mixed evenly, the mixture is cured at 350°C for 1.5 hours in a nitrogen atmosphere to obtain the intercalation modifier.

[0012] A method for preparing a coating material for a high-strength beryllium copper rod comprises the following steps: The beryllium copper rods were cleaned and dried, then micro-arc oxidized at a voltage of 200-300V using a mixture of Na2SiO3 and KOH in a mass ratio of 1:4-5. Laser etching was then performed using a pulsed fiber laser with a wavelength of 1064nm, a pulse width of 10ns, a frequency of 50kHz, a power of 25-35W, a scanning speed of 4-6mm / s, a spot overlap of 45%-50%, and an axial spiral trajectory of the rod with a pitch of 2mm. The Ni-Co-MoS2 composite coating was prepared by electroplating process with a current density of 2-2.5A / dm 2 , temperature 52-60℃, pH value 3.5-4.0, time 30-40min; The beryllium copper rod with the surface electrodeposited is placed in a reaction furnace to form a nanocrystalline Ni-Al transition layer; The plasma spraying composite coating was prepared by plasma spraying process with spraying power of 30-40kW, Ar flow rate of 40-44L / min, powder feeding rate of 24-30g / min, spraying distance of 100-110mm and substrate preheating temperature of 180-200℃.

[0013] Preferably, the cleaning includes alkali cleaning, acid cleaning, and water cleaning; Alkali cleaning is carried out at room temperature using a 10% mass fraction sodium hydroxide solution; Pickling is carried out at room temperature using a 5% sulfuric acid solution; After acid cleaning, rinse with clean water until neutral.

[0014] Preferably, the electroplating bath composition includes: 220-260 g / L nickel sulfate, 100-130 g / L cobalt sulfate, 10-12 g / L sodium chloride, 30-38 g / L boric acid, 10-14 g / L MoS2 nanoparticles, and 0.05-0.07 g / L sodium dodecyl sulfate.

[0015] Preferably, the movement speed of the spray gun in the plasma spraying step is 580-650 mm / s.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, a three-layer composite coating is sequentially electrodeposited on the surface of a beryllium copper rod, comprising a Ni-Co-MoS2 composite coating, an in-situ grown nanocrystalline Ni-Al transition layer, and a plasma sprayed composite coating, thereby significantly improving the coating performance and extending the coating's service life.

[0017] In the present invention, the surface treatment of the substrate includes alkaline washing to remove oil stains and acid washing to etch the oxide layer, so as to reduce the oxygen content on the substrate surface and provide a high-energy adsorption interface for the electrodeposited layer. Through micro-arc oxidation and laser etching, the porous membrane formed by micro-arc oxidation not only provides mechanical locking sites, but also the -OH groups on its surface can also interact with Ni in the electrodeposited layer. 2+ The laser-etched spiral grooves (pitch 2 mm) are distributed along the axial direction of the rod, so that the coating produces a spiral buffer effect when subjected to circumferential force, reducing the propagation of circumferential cracks.

[0018] The electrodeposited Ni-Co-MoS2 composite coating in the present invention serves as a connecting medium between the substrate and the transition layer. The Ni-Co alloy matrix improves the bonding strength with the beryllium copper substrate through the following mechanisms: Metallurgical compatibility: Ni-Co alloy and Cu element in beryllium copper matrix can form solid solution. During the electrodeposition process, Ni 2+ 、Co 2+ The ions are reduced and deposited on the surface of the substrate, and diffuse with the surface atoms of the substrate to form an intermetallic compound transition layer with a thickness of about 0.5-1μm, achieving atomic-level metallurgical bonding.

[0019] Mechanical locking effect: After micro-arc oxidation treatment, the porous structure on the substrate surface is filled with the electrodeposited layer, forming a pinning effect; the spiral grooves produced by laser etching further increase the surface roughness, and the electrodeposited layer grows along the groove contour to form a mechanical interlocking structure, greatly improving the bonding strength; MoS2 nanoparticles are evenly dispersed in the Ni-Co matrix. Although they do not directly participate in friction, they reduce the risk of coating peeling due to stress concentration by regulating the internal stress of the electrodeposited layer, thereby indirectly optimizing the interface bonding stability.

[0020] The in-situ grown nanocrystalline Ni-Al transition layer in the present invention serves as a connecting bridge and strengthens the connection between the electrodeposited layer and the plasma sprayed coating through the following mechanism: Interface stress buffering: The lattice constant of nanocrystalline Ni-Al is close to that of Ni-Co alloy, and the thermal expansion coefficients match each other, which can effectively reduce the thermal stress concentration between the two layers.

[0021] Diffusion enhanced bonding: The Ni-Al alloy powder evaporated in the Ar-H2 atmosphere undergoes a eutectic reaction with the Ni in the electrodeposited layer to form a Ni3Al-Ni solid solution transition zone. At the same time, the Al element chemically bonds with the Al2O3 in the subsequent plasma sprayed coating to achieve a strong and tough connection at the metal-ceramic interface.

[0022] The plasma sprayed composite coating of the present invention, as the main body of wear resistance and corrosion resistance, greatly improves the comprehensive performance of the coating. In the plasma sprayed composite coating, Al2O3 serves as a skeleton phase, providing resistance to plastic deformation; TiO2 fills the Al2O3 grain boundaries, inhibits grain growth, refines the coating microstructure, and improves hardness. The graphene sheets in the intercalation modifier form a network skeleton in the coating. When the crack expands, the graphene sheets slip and peel off, consuming fracture energy; the loaded nano-SiO2 acts as a second-phase particle, producing a dispersion strengthening effect, which significantly improves the fracture toughness of the coating; the polytitanium silazane in the intercalation modifier decomposes to produce a Si-NC lubricating phase, which forms a transfer film together with graphene, reducing the friction coefficient and improving wear resistance. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The present invention provides a coating material for high-strength beryllium copper rods, comprising an electrodeposited Ni-Co-MoS2 composite coating, an in-situ grown nanocrystalline Ni-Al transition layer, and a plasma-sprayed composite coating, sequentially formed on the surface of a substrate. The electrodeposited Ni-Co-MoS2 composite coating has a thickness of 10-15 μm, the in-situ grown nanocrystalline Ni-Al transition layer has a thickness of ≤5 μm, and the plasma-sprayed composite coating has a thickness of 30-40 μm.

[0025] The substrate is a beryllium copper rod. The in-situ growth of the nanocrystalline Ni-Al transition layer is prepared by heating the mixture to 500-550°C in an Ar atmosphere, holding the temperature for 10-15 minutes, then introducing an Ar-H2 mixture (H2 volume fraction 4%-6%) while simultaneously evaporating Ni-Al alloy powder at a rate of 4-6 mL / min. The Ni:Al alloy powder has a Ni:Al atomic ratio of 3:1-1.4 and a particle size of ≤10 μm.

[0026] The spray material of the plasma spray composite coating includes, by mass ratio, 22%-30% of TiO2 powder, 15%-20% of SiO2 powder, 7%-10% of intercalation modifier, and the balance of Al2O3 powder, with an average particle size of 10-15 μm.

[0027] The intercalation modifier is prepared by the following process: 1-2g of graphite powder is mixed with 0.5-0.8g of NaNO3, 60-90mL of 98% concentrated sulfuric acid is added, and the mixture is stirred in an ice bath. 3-4g of KMnO4 is added in 5 portions, and the reaction temperature is controlled to be ≤10°C for 2h; the mixture is heated to 35-38°C and the reaction is continued for 30-40min, 150-180mL of deionized water is slowly added, the mixture is heated to 95°C and the reaction is continued for 15-18min; 5-7mL of 30% hydrogen peroxide is added to terminate the reaction, the mixture is filtered, washed to neutrality and dried to obtain graphene oxide; the graphene oxide is super- The SiO2 / graphene oxide composite material was prepared by acoustic dispersion in 100-110 mL of anhydrous ethanol, adding 2-3 mL of ethyl orthosilicate, stirring for 24-26 hours, and drying at 80°C. The composite material was placed in a mixed gas atmosphere of 5% H2 and 95% Ar and reduced at 800°C for 2-3 hours to obtain graphene-loaded nano-SiO2. Polytitanium silazane (8%-10% of the mass of graphene-loaded nano-SiO2) was added thereto, mixed evenly, and cured at 350°C in a nitrogen atmosphere for 1.5 hours to prepare an intercalation modifier, which was then characterized.

[0028] The preparation method comprises the following steps: sequentially cleaning the beryllium copper rod with alkaline solution (10% sodium hydroxide solution at room temperature), acid solution (5% sulfuric acid solution at room temperature), and water until neutral, drying, and then performing micro-arc oxidation treatment at a voltage of 200-300V and an electrolyte comprising a mixed solution of Na2SiO3 and KOH in a mass ratio of 1:4-5; then performing laser etching using a pulsed fiber laser with a wavelength of 1064nm, a pulse width of 10ns, a frequency of 50kHz, a power of 25-35W, a scanning speed of 4-6mm / s, a spot overlap rate of 45%-50%, and an etching area being an axial spiral trajectory of the rod with a pitch of 2mm; and preparing a Ni-Co-MoS2 composite coating by an electrodeposition process at a current density of 2-2.5A / dm 2 , temperature 52-60°C, pH value 3.5-4.0, time 30-40min; placing the beryllium copper rod with completed surface electrodeposition in a reaction furnace to form a nanocrystalline Ni-Al transition layer; preparing the composite coating by a plasma spraying process, with a spraying power of 30-40kW, an Ar flow rate of 40-44L / min, a powder feeding rate of 24-30g / min, a spraying distance of 100-110mm, a substrate preheating temperature of 180-200°C, and a spray gun moving speed of 580-650mm / s.

[0029] The following are specific embodiments: Example 1 (1) The beryllium copper rod was alkaline cleaned with a 10% sodium hydroxide solution at room temperature for 10 minutes, then acid cleaned with a 5% sulfuric acid solution at room temperature for 8 minutes, and then washed with clean water until neutral and dried; micro-arc oxidation treatment was performed with a voltage of 200 V, an electrolyte of a mixed solution of Na2SiO3 and KOH in a mass ratio of 1:4, and a treatment time of 15 minutes; laser etching was performed using a pulsed fiber laser with a wavelength of 1064 nm, a pulse width of 10 ns, a frequency of 50 kHz, a power of 25 W, a scanning speed of 4 mm / s, a spot overlap rate of 45%, and an etched area of ​​the rod axial spiral trajectory with a pitch of 2 mm.

[0030] (2) Ni-Co-MoS2 composite coating was prepared by electroplating process. The plating solution composition included: nickel sulfate 220 g / L, cobalt sulfate 100 g / L, sodium chloride 10 g / L, boric acid 30 g / L, MoS2 nanoparticles 10 g / L, sodium dodecyl sulfate 0.05 g / L, and the current density was 2 A / dm 2 , temperature 52℃, pH value 3.5, time 30min, the obtained electrodeposited Ni-Co-MoS2 composite coating has a thickness of 10μm.

[0031] (3) The beryllium copper rod with surface electrodeposition was placed in a reactor, heated to 500 °C in an Ar atmosphere, kept warm for 15 min, and introduced an Ar-H2 mixed gas with a H2 volume fraction of 4%. At the same time, Ni-Al alloy powder was evaporated at a rate of 4 mL / min. The Ni:Al atomic ratio in the Ni-Al alloy powder was 3:1, and the particle size was ≤10 μm. An in-situ grown nanocrystalline Ni-Al transition layer with a thickness of 3 μm was formed.

[0032] (4) A plasma sprayed composite coating was prepared by a plasma spraying process. The spraying material included, by mass ratio, 22% TiO2 powder, 15% SiO2 powder, 7% intercalation modifier, and the balance Al2O3 powder, with an average particle size of 10 μm. The spraying power was 30 kW, the Ar flow rate was 40 L / min, the powder feeding rate was 24 g / min, the spraying distance was 100 mm, the substrate preheating temperature was 180 °C, and the spray gun moving speed was 580 mm / s. The obtained plasma sprayed composite coating had a thickness of 30 μm.

[0033] The intercalation modifier was prepared by the following process: 1 g of graphite powder was mixed with 0.5 g of NaNO3, 60 mL of 98% concentrated sulfuric acid was added, and the mixture was stirred in an ice bath. 3 g of KMnO4 was added in 5 portions, and the reaction temperature was controlled to be ≤10°C for 2 h; the mixture was heated to 35°C and the reaction was continued for 30 min, 150 mL of deionized water was slowly added, and the mixture was heated to 95°C for 15 min; 5 mL of 30% hydrogen peroxide was added to terminate the reaction, and the mixture was filtered, washed to neutrality, and dried to obtain graphene oxide; the graphene oxide was ultrasonically treated. The composite material was dispersed in 100 mL of anhydrous ethanol, 2 mL of ethyl orthosilicate was added, stirred for 24 h, and dried at 80 ° C to obtain a SiO2 / graphene oxide composite material; the composite material was placed in a mixed gas atmosphere of 5% H2 volume fraction and 95% Ar volume fraction, and reduced at 800 ° C for 2 h to obtain graphene-loaded nano-SiO2; polytitanium silazane (with a mass of 8% of the mass of graphene-loaded nano-SiO2) was added thereto, mixed evenly, and cured at 350 ° C in a nitrogen atmosphere for 1.5 h to obtain an intercalation modifier.

[0034] Example 2 (1) The specific treatment steps are the same as those in Example 1. The micro-arc oxidation treatment voltage is 250 V, the electrolyte is a mixed solution of Na2SiO3 and KOH in a mass ratio of 1:4.5, and the treatment time is 20 min; the laser etching power is 30 W, the scanning speed is 5 mm / s, and the spot overlap rate is 48%.

[0035] (2) The plating solution composition in the electroplating process includes: nickel sulfate 240g / L, cobalt sulfate 120g / L, sodium chloride 11g / L, boric acid 35g / L, MoS2 nanoparticles 12g / L, sodium dodecyl sulfate 0.06g / L, and the current density is 2.2A / dm 2 , temperature 55℃, pH value 3.8, time 35min, the obtained electrodeposited Ni-Co-MoS2 composite coating has a thickness of 12μm.

[0036] (3) During the preparation of the in situ grown nanocrystalline Ni-Al transition layer, the temperature was raised to 525°C in an Ar atmosphere and kept at this temperature for 12 min. An Ar-H2 mixture was introduced, in which the H2 volume fraction was 5%. At the same time, Ni-Al alloy powder was evaporated at a rate of 5 mL / min. The Ni:Al atomic ratio in the Ni-Al alloy powder was 2:1, the particle size was ≤10 μm, and the thickness of the transition layer formed was 4 μm.

[0037] (4) The spray coating in the plasma spraying process includes, by mass ratio, 25% TiO2 powder, 18% SiO2 powder, 8% intercalation modifier, and the balance Al2O3 powder; the spraying power is 35kW, the Ar flow rate is 42L / min, the powder feeding rate is 27g / min, the spraying distance is 105mm, the substrate preheating temperature is 190℃, the spray gun moving speed is 620mm / s, and the obtained composite coating thickness is 35μm.

[0038] The intercalation modifier was prepared by the following process: 1.5 g of graphite powder was mixed with 0.6 g of NaNO3, 80 mL of 98% concentrated sulfuric acid was added, and the mixture was stirred in an ice bath. 3.5 g of KMnO4 was added in 5 portions, and the reaction temperature was controlled to be ≤10°C for 2 h; the mixture was heated to 36°C and the reaction was continued for 35 min, 160 mL of deionized water was slowly added, and the mixture was heated to 95°C for 17 min; 6 mL of 30% hydrogen peroxide was added to terminate the reaction, and the mixture was filtered, washed to neutrality, and dried to obtain graphene oxide; the graphene oxide was super- The SiO2 / graphene oxide composite material was prepared by acoustic dispersion in 105 mL of anhydrous ethanol, adding 3 mL of ethyl orthosilicate, stirring for 25 h, and drying at 80 °C. The composite material was placed in a mixed gas atmosphere of 5% H2 and 95% Ar, and reduced at 800 °C for 2.5 h to obtain graphene-loaded nano-SiO2. Polytitanium silazane (9% of the mass of graphene-loaded nano-SiO2) was added thereto, mixed evenly, and cured at 350 °C in a nitrogen atmosphere for 1.5 h to obtain an intercalation modifier.

[0039] Example 3 (1) The specific treatment steps are the same as those in Example 1. The micro-arc oxidation treatment voltage is 300 V, the electrolyte is a mixed solution of Na2SiO3 and KOH in a mass ratio of 1:5, and the treatment time is 25 min; the laser etching power is 35 W, the scanning speed is 6 mm / s, and the spot overlap rate is 50%.

[0040] (2) The plating solution composition in the electroplating process includes: nickel sulfate 260g / L, cobalt sulfate 130g / L, sodium chloride 12g / L, boric acid 38g / L, MoS2 nanoparticles 14g / L, sodium dodecyl sulfate 0.07g / L, and the current density is 2.5A / dm 2 , temperature 60℃, pH value 4.0, time 40min, the obtained electrodeposition composite coating thickness is 15μm.

[0041] (3) When growing the transition layer in situ, the temperature was raised to 550 °C in an Ar atmosphere and kept at this temperature for 10 min. An Ar-H2 mixture with a H2 volume fraction of 6% was introduced, and Ni-Al alloy powder (Ni:Al atomic ratio 1.4:1, particle size ≤10 μm) was evaporated at a rate of 6 mL / min. The thickness of the transition layer was 5 μm.

[0042] (4) Plasma spraying: The spray material includes, by mass ratio, 30% TiO2 powder, 20% SiO2 powder, 10% intercalation modifier, and the balance Al2O3 powder; spraying power 40kW, Ar flow rate 44L / min, powder feeding rate 30g / min, spraying distance 110mm, substrate preheating 200℃, spray gun moving speed 650mm / s, and coating thickness 40μm.

[0043] The intercalation modifier was prepared by the following process: 2 g of graphite powder was mixed with 0.8 g of NaNO3, 90 mL of 98% concentrated sulfuric acid was added, and the mixture was stirred in an ice bath. 4 g of KMnO4 was added in 5 portions, and the reaction temperature was controlled to be ≤10°C for 2 h; the mixture was heated to 38°C and the reaction was continued for 40 min, 180 mL of deionized water was slowly added, and the mixture was heated to 95°C for 18 min; 7 mL of 30% hydrogen peroxide was added to terminate the reaction, and the mixture was filtered, washed to neutrality, and dried to obtain graphene oxide; the graphene oxide was ultrasonically separated and the reaction was continued. The composite material was dispersed in 110 mL of anhydrous ethanol, 3 mL of ethyl orthosilicate was added, stirred for 26 h, and dried at 80 ° C to obtain a SiO2 / graphene oxide composite material; the composite material was placed in a mixed gas atmosphere of 5% H2 volume fraction and 95% Ar volume fraction, and reduced at 800 ° C for 3 h to obtain graphene-loaded nano-SiO2; polytitanium silazane (the mass of which was 10% of the mass of graphene-loaded nano-SiO2) was added thereto, mixed evenly, and cured at 350 ° C in a nitrogen atmosphere for 1.5 h to obtain an intercalation modifier.

[0044] Example 4 (1) The specific treatment steps are the same as those in Example 2, and the micro-arc oxidation treatment time is 18 minutes.

[0045] (2) The electrodeposition process was the same as in Example 2, and the thickness of the obtained composite coating was 12 μm.

[0046] (3) When growing the transition layer in situ, the temperature was raised to 510 °C in an Ar atmosphere and kept at this temperature for 14 min. An Ar-H2 mixture with a H2 volume fraction of 4.5% was introduced, and Ni-Al alloy powder (Ni:Al atomic ratio 2.5:1, particle size ≤10 μm) was evaporated at a rate of 4.5 mL / min. The thickness of the transition layer was 3.5 μm.

[0047] (4) The plasma spraying coating material includes, by mass ratio, 23% TiO2 powder, 16% SiO2 powder, 9% intercalation modifier, and the balance Al2O3 powder; the spraying power is 32kW, the Ar flow rate is 41L / min, the powder feeding rate is 25g / min, the spraying distance is 102mm, the substrate is preheated to 185℃, the spray gun movement speed is 590mm / s, and the coating thickness is 32μm.

[0048] The intercalation modifier is the same as that in Example 2.

[0049] Example 5 (1) The specific processing steps are the same as those in Example 3, and the laser etching scanning speed is 5 mm / s.

[0050] (2) The electrodeposition process was the same as in Example 3, and the thickness of the obtained composite coating was 14 μm.

[0051] (3) When growing the transition layer in situ, the temperature was raised to 540 °C in an Ar atmosphere and kept at this temperature for 11 min. An Ar-H2 mixture with a H2 volume fraction of 5.5% was introduced, and Ni-Al alloy powder (Ni:Al atomic ratio 1.8:1, particle size ≤10 μm) was evaporated at a rate of 5.5 mL / min. The thickness of the transition layer was 4.5 μm.

[0052] (4) The plasma spraying coating material includes, by mass ratio, 28% TiO2 powder, 17% SiO2 powder, 7.5% intercalation modifier, and the balance Al2O3 powder; the spraying power is 38kW, the Ar flow rate is 43L / min, the powder feeding rate is 28g / min, the spraying distance is 108mm, the substrate is preheated to 195℃, the spray gun movement speed is 640mm / s, and the coating thickness is 38μm.

[0053] The intercalation modifier is the same as that in Example 2.

[0054] Comparative Example 1: The difference between this comparative example and Example 1 is that the step of in-situ growing the nanocrystalline Ni—Al transition layer is omitted in this comparative example.

[0055] Comparative Example 2: The difference between this comparative example and Example 1 is that the spray coating in the plasma spraying process includes, by mass ratio, 22% TiO2 powder, 15% SiO2 powder, and the balance Al2O3 powder, without an intercalation modifier.

[0056] Comparative Example 3: This comparative example differs from Example 1 in that no laser etching process is performed.

[0057] Test example test Wear resistance test (refer to GB / T3960-1983) Using an MMW-1 universal friction and wear tester, a 50N load was applied to the coating specimens. The counterweight was a GCr15 bearing steel ball (6mm diameter). The rotation speed was 200r / min, and the friction time was 30min. The test environment was at a temperature of 25°C ± 2°C and a humidity of 50% ± 5%. The mass loss of the specimens before and after wear was measured, and the wear rate was calculated. Table 1 It can be seen from Table 1 that the coating material prepared by the present invention has a low wear rate and exhibits excellent wear resistance.

[0058] Microhardness test (refer to GB / T9259-2002) Use HVS-1000 microhardness tester, load 50g, hold load time 15s, select 5 different locations on the coating surface for testing, and take the average value; Table 2 It can be seen from Table 2 that the surface microhardness of the coating material prepared by the present invention is greatly improved.

[0059] Bond strength test (refer to GB / T5270-1985) A WS-2005 coating adhesion automatic scratch tester was used with a diamond indenter tip curvature radius of 200 μm and a loading rate of 100 N / min until the coating peeled off and the critical load value was recorded. Table 3 It can be seen from Table 3 that the coating material prepared by the present invention has a high bonding strength with the substrate.

[0060] The high-strength beryllium copper rod coating material provided by the present invention significantly improves the wear resistance, microhardness and bonding strength of the coating through a specific coating structure design and preparation process, solves the problem of insufficient coating performance in the prior art, and has good application prospects.

[0061] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A coating material for high-strength beryllium copper rod, characterized in that: The method comprises the following steps: forming an electrodeposited Ni-Co-MoS2 composite coating, an in-situ grown nanocrystalline Ni-Al transition layer, and a plasma sprayed composite coating on the substrate surface in sequence; The thickness of the electrodeposited Ni-Co-MoS2 composite coating is 10-15 μm, the thickness of the in-situ grown nanocrystalline Ni-Al transition layer is ≤5 μm, and the thickness of the plasma sprayed composite coating is 30-40 μm.

2. The coating material according to claim 1, characterized in that The in-situ grown nanocrystalline Ni-Al transition layer is prepared by heating the material to 500-550°C in an Ar atmosphere, keeping the temperature for 10-15 minutes, introducing an Ar-H2 mixed gas with a H2 volume fraction of 4%-6%, and evaporating Ni-Al alloy powder at a rate of 4-6 mL / min. The Ni:Al atomic ratio in the Ni-Al alloy powder is 3:1-1.4, and the particle size is ≤10μm.

3. The coating material according to claim 1, characterized in that The spray coating of the plasma spray composite coating comprises, by mass ratio, 22%-30% of TiO2 powder, 15%-20% of SiO2 powder, 7%-10% of intercalation modifier, and the balance of Al2O3 powder; The average particle size is 10-15μm.

4. The coating material according to claim 3, characterized in that The intercalation modifier is prepared by the following process: Mix 1-2 g of graphite powder with 0.5-0.8 g of NaNO3, add 60-90 mL of 98% concentrated sulfuric acid, stir in an ice bath, add 3-4 g of KMnO4 in 5 portions, control the reaction temperature to ≤10°C and react for 2 hours; heat to 35-38°C and continue to react for 30-40 minutes, slowly add 150-180 mL of deionized water, heat to 95°C and react for 15-18 minutes; add 5-7 mL of 30% hydrogen peroxide to terminate the reaction, filter, wash to neutrality and dry to obtain graphene oxide; The graphene oxide prepared above was ultrasonically dispersed in 100-110 mL of anhydrous ethanol, 2-3 mL of ethyl orthosilicate was added, and the mixture was stirred for 24-26 hours and then dried at 80° C. to prepare a SiO2 / graphene oxide composite material; The SiO2 / graphene oxide composite material was placed in a mixed gas atmosphere of 5% H2 and 95% Ar, and reduced at 800°C for 2-3h to obtain graphene-loaded nano-SiO2. Polytitanium silazane is added to the graphene-supported nano-SiO2, with the mass of the polytitanium silazane being 8%-10% of the mass of the graphene-supported nano-SiO2. After being mixed evenly, the mixture is cured at 350°C for 1.5 hours in a nitrogen atmosphere to obtain the intercalation modifier.

5. The method for preparing a coating material for a high-strength beryllium copper rod according to any one of claims 1 to 4, characterized in that: The following steps are involved: The beryllium copper rods were cleaned and dried, then micro-arc oxidized at a voltage of 200-300V using a mixture of Na2SiO3 and KOH in a mass ratio of 1:4-5. Laser etching was then performed using a pulsed fiber laser with a wavelength of 1064nm, a pulse width of 10ns, a frequency of 50kHz, a power of 25-35W, a scanning speed of 4-6mm / s, a spot overlap of 45%-50%, and an axial spiral trajectory of the rod with a pitch of 2mm. The Ni-Co-MoS2 composite coating was prepared by electroplating process with a current density of 2-2.5A / dm 2 , temperature 52-60℃, pH value 3.5-4.0, time 30-40min; The beryllium copper rod with the surface electrodeposited is placed in a reaction furnace to form a nanocrystalline Ni-Al transition layer; The plasma spraying composite coating was prepared by plasma spraying process with spraying power of 30-40kW, Ar flow rate of 40-44L / min, powder feeding rate of 24-30g / min, spraying distance of 100-110mm and substrate preheating temperature of 180-200℃.

6. The preparation method according to claim 5, characterized in that The cleaning includes alkali cleaning, acid cleaning, and water cleaning; Alkali cleaning is carried out at room temperature using a 10% mass fraction sodium hydroxide solution; Pickling is carried out at room temperature using a 5% sulfuric acid solution; After acid cleaning, rinse with clean water until neutral.

7. The preparation method according to claim 5, characterized in that The electroplating bath composition includes: 220-260 g / L nickel sulfate, 100-130 g / L cobalt sulfate, 10-12 g / L sodium chloride, 30-38 g / L boric acid, 10-14 g / L MoS2 nanoparticles, and 0.05-0.07 g / L sodium dodecyl sulfate.

8. The preparation method according to claim 5, characterized in that The moving speed of the spray gun in the plasma spraying step is 580-650 mm / s.

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