Preparation method of nano ceramic high-performance composite film layer on surface of copper alloy

Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to a preparation method of a nano ceramic high-performance composite film layer on the surface of a copper alloy. The membrane layer is an electrochemical nano ceramic high performance-organic silicon composite membrane layer, and an electrolyte for forming the electrochemical nano ceramic high performance membrane layer comprises the following components: 8-10 g / L of sodium silicate, 2-5 g / L of potassium hydroxide, 1-2 g / L of sodium citrate, 5-10 ml / L of a self-dispersing nano insulating emulsion containing an anionic electrolyte, 2-4 g / L of zircon salt, 2-5 g / L of high-insulation nanoparticles, 5-10 ml / L of an organic additive and the balance of water. A spraying liquid for forming the organic silicon film layer comprises the following components in percentage by mass: 75-85% of organic silicon resin, 5-15% of a thinner and 5-15% of a curing agent. The comprehensive performance of corrosion resistance, wear resistance and insulativity of the copper alloy can be improved, and the use requirement for high protection performance of a copper alloy product in a severe environment is met.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment technology, specifically relating to a method for preparing a high-performance nano-ceramic composite film layer on the surface of copper alloys. It is applicable to copper alloy components that require high insulation, corrosion resistance, and wear resistance, and is especially suitable for electrical equipment components and copper alloy products used in marine environments. Background Technology

[0002] Copper alloys possess excellent electrical and thermal conductivity, wear resistance, and machinability, making them widely used in electronics, power, aerospace, and high-precision machining fields. Compared to other metals or alloys, copper alloys, by adding appropriate amounts of alloying elements such as beryllium, aluminum, and nickel, significantly improve the material's strength and hardness, resulting in excellent performance under high loads and frequent mechanical vibrations, and resistance to fatigue fracture. Simultaneously, copper alloys exhibit good hot working and machinability, maintaining high plasticity during hot forging and hot pressing, making them suitable for manufacturing demanding mechanical parts. Furthermore, copper alloys can be used to manufacture high-strength and fatigue-resistant precision components, such as springs, aerospace instrument parts, and high-speed cutting tools. Their high strength, toughness, and excellent wear resistance ensure long-term stable operation of these components under high loads and harsh working conditions. More importantly, in the electrical industry and electronic equipment fields, copper alloys are widely used to manufacture miniature sensors, precision connectors, and other components requiring high surface finish, providing reliable support for high-end equipment. They are also used to manufacture critical components such as high-reliability relay contacts, electrical switch springs, and connectors. Their excellent conductivity and wear resistance ensure that equipment maintains stable electrical performance and low contact resistance under long-term, high-frequency operation. However, under certain special conditions, such as in electrical equipment, some copper alloy components need to have insulation properties to prevent current leakage, short circuits, and other problems. Traditional insulation methods, such as coating with organic insulating varnishes, have drawbacks such as poor adhesion, insufficient wear resistance, and inadequate high-temperature resistance, making it difficult to meet the requirements of modern industry for high-performance insulating coatings. Furthermore, when copper alloys are used in harsh environments such as the ocean, they are prone to chemical reactions with oxygen and water vapor in the humid marine environment, forming corrosion products such as verdigris, which affects the protective performance and service life of the copper alloy.

[0003] Current methods for addressing corrosion on copper alloy surfaces or providing localized insulation protection primarily involve coating with organic insulating paints. This paint application forms a protective film on the copper surface, preventing contact with oxygen and moisture, slowing oxidation, and preventing rust and corrosion, thus extending its service life. However, organic insulating coatings suffer from drawbacks such as poor adhesion, insufficient wear resistance, and inadequate high-temperature resistance, making it difficult to meet the demands of modern industry for high-performance corrosion-resistant and insulating coatings.

[0004] Micro-arc oxidation (MAO) is a method for in-situ growth of ceramic films on metal surfaces. The resulting MAO films exhibit high hardness, good wear resistance, and excellent insulation properties. It is widely used on light alloys such as aluminum, magnesium, and titanium because these alloys possess a passivation zone during the early stages of MAO, allowing the formation of a passivation film layer, which in turn leads to the formation of the MAO film layer. Therefore, these metals are conventionally referred to as "valve metals." Copper alloys, however, are non-valve metals and cannot form a chemically stable and insulating oxide film under specific conditions. Consequently, research on the preparation of locally insulating composite coatings using MAO on copper alloys is currently limited, and existing technologies face certain difficulties in achieving localized MAO and controlling coating performance.

[0005] The patent with publication number CN119101977A proposes a method for preparing a Co-Cu-P-Al2O3 nanocomposite coating with high hardness and excellent corrosion resistance. The pulse electroplating system designed for carbon steel is not suitable for the high thermal conductivity and special electrochemical characteristics of copper alloys. When directly applied to the surface of copper alloys, the adhesion will drop sharply due to the imbalance of electrochemical potential difference between the substrate and the coating. In addition, the high concentration of cobalt salt in the electroplating solution is prone to displacement reaction on the surface of copper alloys, forming a loose precursor layer. This coating focuses on corrosion resistance and hardness, but does not consider the thermal conductivity that copper alloy components often need to consider. The introduction of cobalt and phosphorus elements in the coating will significantly reduce the thermal conductivity of the copper alloy substrate, which cannot meet the use requirements of electronic heat dissipation, heat exchange equipment and other scenarios. The patent with publication number CN110093604A proposes a method for preparing a high-performance conductive nano-ceramic metal cladding coating on a pure copper surface. Although the substrate is copper-based, it is only applicable to industrial pure copper. Copper alloys (such as Cr-Zr-Cu, H62 brass, etc.) have complex oxide film composition due to the presence of alloying elements. The sol-gel formulation and laser cladding parameters cannot overcome the obstacles of the alloy oxide film, and the coating is prone to interface peeling. Laser cladding requires a high power input of 2800-3200W. The high energy density can easily cause the formation of coarse intermetallic compounds between the copper alloy substrate and the coating, reducing the bonding strength.

[0006] Therefore, developing a surface strengthening method that is suitable for the properties of copper alloys, meets multiple performance requirements, and is process-friendly has become an urgent technical problem to be solved in this field. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for preparing a high-performance nano-ceramic composite film on the surface of copper alloys. This method forms a plasma-electrochemical nano-ceramic high-performance-organosilicon composite film on the surface of copper alloys, thereby improving the comprehensive performance of copper alloys in terms of insulation, high temperature resistance, corrosion resistance, and wear resistance, and meeting the protective requirements of copper alloy products in harsh environments such as the ocean.

[0008] The technical solution of this invention is: A method for preparing a high-performance nano-ceramic composite film on a copper alloy surface, wherein the film is an electrochemical nano-ceramic high-performance-organosilicon composite film, and the electrolyte forming the electrochemical nano-ceramic high-performance film comprises the following components: sodium silicate 8-10 g / L, potassium hydroxide 2-5 g / L, sodium citrate 1-2 g / L, self-dispersing nano-insulating emulsion containing anionic electrolyte 5-10 ml / L, zirconium salt 2-4 g / L, highly insulating nanoparticles 2-5 g / L, organic additives 5-10 ml / L, and the remainder being water; the spraying liquid forming the organosilicon film comprises, by mass percentage, 75-85% organosilicon resin, 5-15% thinner, and 5-15% curing agent.

[0009] The method for preparing the high-performance composite nano-ceramic film on the surface of the copper alloy, wherein the electrolyte of the electrochemical high-performance nano-ceramic film contains a self-dispersible nano-insulating emulsion with anionic electrolyte, which is a polytetrafluoroethylene emulsion; a zirconium salt, which is one or more of potassium fluorozirconate, zirconium nitrate, and zirconium sulfate; high-insulating nanoparticles, which are one or more of aluminum oxide, silicon carbide, and titanium dioxide particles; and an organic additive, which is one or more of 1,2-propanediol, glycerol, ethanolamine, and triethanolamine.

[0010] The method for preparing the high-performance composite nano-ceramic film on the surface of the copper alloy, wherein the silicone film coating liquid contains a high-temperature curing modified epoxy silicone resin, xylene as the thinner, and hydrogen-containing silicone oil as the curing agent.

[0011] The method for preparing the high-performance nano-ceramic composite film on the surface of the copper alloy described herein uses analytically pure components.

[0012] The method for preparing the high-performance nano-ceramic composite film on the surface of the copper alloy includes the following steps: Step 1, Copper alloy surface pretreatment: Clean the copper alloy by degreasing, and then polish it step by step with 240#, 600#, 1000# and 1200# wet sandpaper; Step 2, Electrolyte preparation: Highly insulating nanoparticles and zirconium salt are added to the basic electrolyte formed by sodium silicate, potassium hydroxide, sodium citrate and water. At the same time, a self-dispersible nano-insulating emulsion containing anionic electrolyte and organic additives are added. By stirring, the anionic electrolyte is adsorbed on the surface of the highly insulating nanoparticles to form anionic groups, while preventing stratification. Step 3, Electrochemical nano-ceramic oxidation: The pretreated copper alloy is used as the anode and the graphite plate is used as the cathode. It is placed in the electrolyte prepared in step (2) and the copper alloy is electrochemically oxidized by spark discharge using a high voltage pulse method to form a high-performance electrochemical nano-ceramic film on the surface of the copper alloy. Step 4, Composite Organosilicon Film Layer: Spray an organosilicon film layer coating solution onto the surface of the copper alloy electrochemical nano-ceramic high-performance film layer, and dry it to form an electrochemical nano-ceramic high-performance-organosilicon composite film layer.

[0013] In the method for preparing the high-performance nano-ceramic composite film on the copper alloy surface, step 3 involves an electrolyte temperature of 20–50°C and specific high-voltage pulse conditions of: pulse frequency of 200–500 Hz, pulse voltage of 500–750 V, and current density of 2–8 A / dm³. 2 Oxidation time: 20–60 min.

[0014] In the method for preparing the high-performance composite nano-ceramic film on the surface of the copper alloy, in step 4, before spraying the silicone film onto the surface of the electrochemical nano-ceramic high-performance film, the copper alloy electrochemical nano-ceramic high-performance film is first subjected to an etching treatment. The specific etching conditions are as follows: the copper alloy electrochemical nano-ceramic high-performance film is etched in hydrofluoric acid with a mass concentration of 5-10% at room temperature for 2-5 seconds, then immediately rinsed with clean water for 1-2 minutes, and then rinsed with deionized water for 1-2 minutes.

[0015] In the preparation method of the high-performance composite nano-ceramic film on the surface of the copper alloy, the specific conditions for spraying in step 4 are: spraying temperature 20-35℃, spraying pressure 1.5-2.5 MPa, spraying distance 20-50 mm, and drying conditions after spraying are: drying temperature 100-120℃, drying time 20-40 min.

[0016] In the method for preparing the high-performance composite film of nano-ceramics on the surface of copper alloy, in step 4, the total thickness of the high-performance composite film of copper alloy nano-ceramics-organosilicon is 80-100 μm; wherein, the thickness of the electrochemical nano-ceramic high-performance film is 20-40 μm, and the thickness of the organosilicon film is 50-80 μm.

[0017] The design concept of this invention is: In existing technologies, the adhesion between the copper alloy surface and the ceramic film is low and easily peeled off. Strengthening processes result in poor performance of the copper alloy substrate, and the film cannot simultaneously achieve high hardness, corrosion resistance, and thermal conductivity of the substrate. Traditional micro-arc oxidation technology is only suitable for valve metals such as aluminum, magnesium, and titanium; copper alloys cannot form a stable insulating oxide film. Organic insulating varnishes suffer from poor adhesion and insufficient wear and high-temperature resistance. In this invention, the high-performance composite film layer on the copper alloy surface consists of a nano-ceramic oxide film at the bottom layer. A base electrolyte is prepared using sodium silicate and potassium hydroxide, with the addition of highly insulating nanoparticles (such as alumina, silicon carbide, and titanium dioxide), zirconium salt, and polytetrafluoroethylene emulsion. High-voltage pulsed discharge oxidation is used to grow the nano-ceramic film in situ on the copper alloy surface. The anionic electrolyte adsorption prevents particle delamination, endowing the coating with basic insulation, corrosion resistance, and wear resistance. The upper layer is an organosilicon film, made of high-temperature cured modified epoxy organosilicon resin, combined with xylene thinner and hydrogen-containing silicone oil curing agent. This is sprayed onto the surface of the nano-ceramic film and dried at low temperature to further enhance insulation performance and coating adhesion, while also improving high-temperature resistance and weather resistance. A step-by-step grinding pretreatment enhances the surface activity of the substrate, and the electrochemical oxidation parameters (20–50℃, 200–500Hz pulse frequency) are controlled to suit the electrochemical response of copper alloys. Short-term hydrofluoric acid etching optimizes the surface roughness of the ceramic film, ensuring a tight bond between the two film layers.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: This invention achieves insulation, corrosion resistance, and wear resistance of copper alloy substrates by preparing electrochemical nano-ceramic high-performance-organosilicon composite films on copper alloy surfaces. Through the synergistic effect of pretreatment, electrochemical in-situ growth, and etching treatment, the nano-ceramic film and the copper alloy substrate, as well as the organosilicon film and the nano-ceramic film, form a tight bond without peeling or flaking, thus solving the defect of poor adhesion of traditional organic coatings.

[0019] This invention first adds highly insulating nanoparticles and anionic electrolyte to an electrochemical nanoceramic high-performance electrolyte. Through stirring, the anionic electrolyte is adsorbed onto the surface of the nanoparticles to form anionic groups. Then, a copper alloy is placed in the electrochemical nanoceramic high-performance electrolyte as the anode, and a graphite plate as the cathode. Electrochemical nanoceramic spark discharge oxidation is performed on the copper alloy using a high-voltage pulse method, forming a high-performance nanoceramic oxide film on the copper alloy surface. Finally, the copper alloy nanoceramic oxide film is composite-treated with an organosilicon spray solution to form a plasma-electrochemical nanoceramic high-performance-organosilicon composite film. The electrochemical nanoceramic high-performance-organosilicon composite film prepared on the copper alloy surface by this invention has the advantages of high insulation, high corrosion resistance, and high wear resistance, meeting the high-strength protective requirements of copper alloys in harsh marine environments.

[0020] 3. This invention is applicable to copper alloys such as brass, H62, H68, and HPb-59-1. The process is mild and has a wide range of applications. The electrochemical oxidation temperature is 20-50℃ and the drying temperature is 100-120℃, which avoids affecting the properties of the copper alloy matrix and can meet the needs of multiple fields such as electronics, power, and marine engineering. Attached Figure Description

[0021] Figure 1 Macroscopic image of the electrochemical nano-ceramic oxide film layer on the surface of a copper alloy.

[0022] Figure 2 This image shows the surface state of a copper alloy electrochemical nanoceramic high-performance-organosilicon composite film after 2500 hours of neutral salt spray.

[0023] Figure 3 The image shows the surface condition of the copper alloy electrochemical nano-ceramic high-performance organosilicon composite film after a tribological wear test (1kg grinding wheel, 1000 rpm, 80mg wear, no bottom leakage). Detailed Implementation

[0024] The present invention will be further explained below with reference to specific implementation schemes, but this is not intended to limit the scope of protection of the present invention.

[0025] Example 1

[0026] In this embodiment, a method for preparing a high-performance nano-ceramic composite film on a copper alloy surface is as follows: 1. Material preparation: H62 brass alloy pretreatment, i.e. after cutting, grinding and polishing, is ultrasonically cleaned in acetone solution to remove oil, and then polished with 240#, 600#, 1000# and 1200# wet sandpaper in stages until there are no obvious scratches on the surface. Then it is rinsed with deionized water and air dried. 2. Preparation of high-performance oxide films using plasma-enhanced nanoceramics: (1) Electrolyte composition: sodium silicate 8 g / L, potassium hydroxide 2 g / L, sodium citrate 1 g / L, polytetrafluoroethylene emulsion 5 ml / L, potassium fluorozirconate 2 g / L, nano aluminum oxide particles 2 g / L, 1,2-propanediol 5 ml / L, the remainder being water; wherein, the polytetrafluoroethylene emulsion is selected from Chemours Teflon FEPD 121D polytetrafluoroethylene emulsion produced by DuPont (Chemours Chemical Company).

[0027] (2) Preparation process: The copper alloy sample (as the anode) was placed in the high-performance electrochemical nano-ceramic electrolyte and subjected to electrochemical nano-ceramic spark discharge oxidation using a high-voltage pulse method. The pulse frequency was 200Hz, the pulse voltage was 500V, and the current density was 2A / dm³. 2The oxidation time was 60 min, and the resulting electrochemical nanoceramic oxide film had a thickness of 20–25 μm. Figure 1 As shown.

[0028] 3. Preparation of organosilicon film: Etching treatment: Immerse the nano-ceramic oxide film in 5% hydrofluoric acid at room temperature for 2 seconds, remove and rinse with water for 1 minute, then rinse with deionized water for 1 minute. An organosilicon lubricating film is composited on the surface of an electrochemical nano-ceramic oxide film. The composition of the lubricating film is 80 wt% organosilicon resin, 10 wt% thinner, and 10 wt% curing agent. The organosilicon resin is a high-temperature curing modified epoxy organosilicon resin, such as MSE100 organosilicon resin produced by Wacker Chemie AG. The thinner is xylene, and the curing agent is hydrogen-containing silicone oil, such as KF-9901 hydrogen-containing silicone oil produced by Shin-Etsu Chemical Co., Ltd. of Japan.

[0029] The silicone resin spraying temperature was 20–25℃, the spraying pressure was 1.5 MPa, and the spraying distance was 20–30 mm. After spraying, the drying conditions were: drying temperature 100℃, drying time 30 min. The total thickness of the electrochemical nano-ceramic high-performance-organic silicone composite film was 80–90 μm. Figure 2 As shown.

[0030] The surface Vickers hardness of the electrochemical nano-ceramic high-performance-organic silicon composite film obtained in this embodiment can reach up to 380 HV; the resistance to neutral salt spray test can reach more than 1000 h; the wear resistance: 1kg grinding wheel at 1000 rpm, the wear amount is 80mg, and there is no leakage; the dry insulation point resistance can reach 100MΩ or more under DC voltage of 1000V.

[0031] Example 2

[0032] In this embodiment, a method for preparing a high-performance nano-ceramic composite film on a copper alloy surface is as follows: 1. Material preparation: H68 copper alloy pretreatment, i.e. after cutting, grinding and polishing, is ultrasonically cleaned in alkaline washing solution to remove oil, and then polished with 240#, 600#, 1000# and 1200# wet sandpaper in stages until there are no obvious scratches on the surface. Then it is rinsed with deionized water and air dried. 2. Preparation of high-performance oxide films using plasma-enhanced nanoceramics: (1) Electrolyte composition: sodium silicate 10g / L, potassium hydroxide 5g / L, sodium citrate 2g / L, polytetrafluoroethylene emulsion 10ml / L, potassium fluorozirconate 4g / L, nano silicon carbide particles 5g / L, glycerol 10ml / L, the remainder being water; wherein, the polytetrafluoroethylene emulsion is selected from Chemours Teflon FEPD 121D polytetrafluoroethylene emulsion produced by DuPont (Chemours Chemical Company).

[0033] (2) Preparation process: The copper alloy sample (as the anode) was placed in the high-performance electrochemical nano-ceramic electrolyte and subjected to electrochemical nano-ceramic spark discharge oxidation using a high-voltage pulse method. The pulse frequency was 500 Hz, the pulse voltage was 750 V, and the current density was 8 A / dm³. 2 The oxidation time was 20 min, and the thickness of the resulting electrochemical nanoceramic oxide film was 35–40 μm.

[0034] 3. Preparation of organosilicon film: Etching treatment: Immerse in 10% hydrofluoric acid at room temperature for 5 seconds, rinse with clean water for 2 minutes, and rinse with deionized water for 2 minutes. An organosilicon lubricating film is composited on the surface of an electrochemical nano-ceramic oxide film. The composition of the lubricating film is 80 wt% organosilicon resin, 10 wt% thinner, and 10 wt% curing agent. The organosilicon resin is a high-temperature curing modified epoxy organosilicon resin, such as MSE100 organosilicon resin produced by Wacker Chemie AG. The thinner is xylene, and the curing agent is hydrogen-containing silicone oil, such as KF-9901 hydrogen-containing silicone oil produced by Shin-Etsu Chemical Co., Ltd. of Japan.

[0035] The silicone resin spraying temperature is 30-35℃, the spraying pressure is 2.5MPa, the spraying distance is 40-50mm, and the drying conditions after spraying are: drying temperature 120℃, drying time 30min, and the total thickness of the electrochemical nano-ceramic high-performance-organic silicone composite film is 90-100 μm.

[0036] The electrochemical nanoceramic high-performance-organic silicon composite film obtained in this embodiment has a maximum surface Vickers hardness of 380 HV; its resistance to neutral salt spray testing exceeds 2500 h; its wear resistance is 80 mg with a 1 kg grinding wheel at 1000 rpm, and it does not leak. Figure 3 As shown, the dry insulation point resistance can reach 100MΩ or higher at a DC voltage of 1000V.

[0037] Example 3

[0038] In this embodiment, a method for preparing a high-performance nano-ceramic composite film on a copper alloy surface is as follows: 1. Material preparation: HPb-59-1 leaded brass alloy pretreatment, i.e. after cutting, grinding and polishing, is ultrasonically cleaned in alkaline washing solution to remove oil, and then polished with 240#, 600#, 1000# and 1200# wet sandpaper in stages until there are no obvious scratches on the surface. Then it is rinsed with deionized water and air dried. 2. Preparation of high-performance oxide films using plasma-enhanced nanoceramics: (1) Electrolyte composition: sodium silicate 8 g / L, potassium hydroxide 5 g / L, sodium citrate 2 g / L, polytetrafluoroethylene emulsion 8 ml / L, potassium fluorozirconate 3 g / L, nano titanium dioxide particles 5 g / L, ethanolamine 5 ml / L, triethanolamine 5 ml / L, the remainder being water; among which, the polytetrafluoroethylene emulsion is selected from Chemours Teflon FEPD 121D polytetrafluoroethylene emulsion produced by DuPont (Chemours Chemical Company).

[0039] (2) Preparation process: The copper alloy sample (as the anode) was placed in the high-performance electrochemical nano-ceramic electrolyte and subjected to electrochemical nano-ceramic spark discharge oxidation using a high-voltage pulse method. The pulse frequency was 300 Hz, the pulse voltage was 650 V, and the current density was 4 A / dm³. 2 The oxidation time was 30 min, and the thickness of the resulting electrochemical nanoceramic oxide film was 30–35 μm.

[0040] 3. Preparation of organosilicon film: Etching treatment: Immerse in 8% hydrofluoric acid at room temperature for 3 seconds, rinse with clean water for 1.5 minutes, and rinse with deionized water for 1.5 minutes; An organosilicon lubricating film is composited on the surface of an electrochemical nano-ceramic oxide film. The composition of the lubricating film is 80 wt% organosilicon resin, 10 wt% thinner, and 10 wt% curing agent. The organosilicon resin is a high-temperature curing modified epoxy organosilicon resin, such as MSE100 organosilicon resin produced by Wacker Chemie AG. The thinner is xylene, and the curing agent is hydrogen-containing silicone oil, such as KF-9901 hydrogen-containing silicone oil produced by Shin-Etsu Chemical Co., Ltd. of Japan.

[0041] The silicone resin spraying temperature is 25-30℃, the spraying pressure is 2.0MPa, the spraying distance is 30-40mm, and the drying conditions after spraying are: drying temperature 100℃, drying time 30min, and the total thickness of the electrochemical nano-ceramic high-performance-organic silicone composite film is 90-100 μm.

[0042] The surface Vickers hardness of the electrochemical nano-ceramic high-performance-organic silicon composite film obtained in this embodiment can reach up to 380 HV; the resistance to neutral salt spray test is over 2500 h; the wear resistance is 80 mg with a 1 kg grinding wheel at 1000 rpm and no leakage; the dry insulation point resistance can reach 100 MΩ or above under a DC voltage of 1000 V.

[0043] The results show that this invention can improve the comprehensive performance of copper alloys in terms of corrosion resistance, wear resistance, and insulation. The dry insulation point resistance reaches 100MΩ or above under a DC voltage of 1000V, effectively solving the problems of current leakage and short circuit in copper alloy electrical components. It can withstand neutral salt spray tests for 1000-2500 hours, resisting corrosion in humid marine environments. The maximum Vickers hardness is 380HV, and the wear is 80mg under the condition of 1kg grinding wheel at 1000 rpm, without leakage, and has good wear resistance. Through electrochemical in-situ growth and surface etching treatment, the coating is tightly bonded to the copper alloy substrate without peeling or flaking, meeting the high protective performance requirements of copper alloy products in harsh environments.

Claims

1. A method for preparing a copper alloy surface nanoceramic high-performance composite film layer, characterized in that, The film layer is an electrochemical nanoceramic high-performance-silicone composite film layer, and the electrolyte for forming the electrochemical nanoceramic high-performance film layer comprises the following components: 8-10 g / L of sodium silicate, 2-5 g / L of potassium hydroxide, 1-2 g / L of sodium citrate, 5-10 ml / L of self-dispersing nanometer insulating emulsion containing an anion electrolyte, 2-4 g / L of zirconium salt, 2-5 g / L of high-insulation nanometer particles, 5-10 ml / L of organic additive, and the rest is water; and the spraying liquid for forming the silicone film layer comprises, in percentage by mass, 75-85% of silicone resin, 5-15% of thinner, and 5-15% of curing agent.

2. The method of claim 1, wherein the copper alloy surface nanoceramic high performance composite film layer is prepared by the steps of: (a) preparing a copper alloy substrate; (b) preparing a copper alloy surface nanoceramic high performance composite film layer on the copper alloy substrate by a physical vapor deposition method. In the electrolyte for forming the electrochemical nanoceramic high-performance film layer, the self-dispersing nanometer insulating emulsion containing an anion electrolyte is a polytetrafluoroethylene emulsion, the zirconium salt is one or two or more of potassium fluorozirconate, zirconium nitrate and zirconium sulfate, the high-insulation nanometer particles are one or two or more of aluminum oxide, silicon carbide and titanium dioxide particles, and the organic additive is one or two or more of 1,2-propanediol, glycerol, ethanolamine and triethanolamine.

3. The method for preparing a high-performance nano-ceramic composite film on a copper alloy surface according to claim 1, characterized in that, In the spraying liquid for the silicone film layer, the silicone resin is a high-temperature curing modified epoxy silicone resin, the thinner is dimethylbenzene, and the curing agent is hydrogen-containing silicone oil.

4. The method for preparing a high-performance nano-ceramic composite film on a copper alloy surface according to claim 1, characterized in that, All the components are of analytical purity.

5. The method for preparing the copper alloy surface nanometer ceramic high performance composite film layer according to any one of claims 1-4, characterized in that, The method comprises the following steps: Step 1: copper alloy surface pretreatment: the copper alloy is subjected to oil removal cleaning and is polished by 240#, 600#, 1000# and 1200# water abrasive paper in sequence; Step 2: electrolyte preparation: in a base electrolyte formed by sodium silicate, potassium hydroxide, sodium citrate and water, high-insulation nanometer particles and zirconium salt are added, and self-dispersing nanometer insulating emulsion containing an anion electrolyte and organic additive are also added, the anion electrolyte is adsorbed on the surface of the high-insulation nanometer particles by stirring to form anion groups, and stratification is prevented; Step 3: electrochemical nanoceramic oxidation: the pretreated copper alloy is used as an anode, a graphite plate is used as a cathode, and the copper alloy is subjected to electrochemical nanoceramic spark discharge oxidation in the electrolyte prepared in step (2) by using high-voltage pulse mode, so that an electrochemical nanoceramic high-performance film layer is formed on the surface of the copper alloy; Step 4: composite silicone film layer: the spraying liquid for the silicone film layer is sprayed on the surface of the electrochemical nanoceramic high-performance film layer of the copper alloy, and is dried to form an electrochemical nanoceramic high-performance-silicone composite film layer.

6. The method of claim 5, wherein the copper alloy surface nanoceramic high performance composite film layer is prepared by the steps of: (a) preparing a copper alloy substrate; (b) preparing a copper alloy surface nanoceramic high performance composite film layer on the copper alloy substrate by a physical vapor deposition method. In step 3, the temperature of the electrolyte is 20-50°C, and the specific conditions of the high-voltage pulse are: pulse frequency 200-500 Hz, pulse voltage 500-750 V, current density 2-8 A / dm 2 , oxidation time 20-60 min.

7. The method of claim 5, wherein the copper alloy surface nanoceramic high performance composite film layer is prepared by the steps of: (a) preparing a copper alloy substrate; (b) preparing a copper alloy surface nanoceramic high performance composite film layer on the copper alloy substrate by a physical vapor deposition method. In step 4, before the spraying liquid for the silicone film layer is sprayed on the surface of the electrochemical nanoceramic high-performance film layer of the copper alloy, the electrochemical nanoceramic high-performance film layer of the copper alloy is subjected to etching treatment, and the etching treatment is performed in the following conditions: the electrochemical nanoceramic high-performance film layer of the copper alloy is immersed in hydrofluoric acid with a mass concentration of 5-10% at room temperature for 2-5 s, is taken out immediately, is cleaned with clean water for 1-2 min, and is cleaned with deionized water for 1-2 min.

8. The method for preparing a high-performance nano-ceramic composite film on a copper alloy surface according to claim 5, characterized in that, In step 4, the spraying is performed in the following conditions: the spraying temperature is 20-35 ℃, the spraying pressure is 1.5-2.5 MPa, and the spraying distance is 20-50 mm; and the drying conditions after the spraying are as follows: the drying temperature is 100-120 ℃, and the drying time is 20-40 min.

9. The method for preparing a high-performance nano-ceramic composite film on a copper alloy surface according to claim 5, characterized in that, In step 4, the total thickness of the copper alloy nanoceramic high-performance-silicone composite film layer is 80-100 microns; wherein the thickness of the electrochemical nanoceramic high-performance film layer is 20-40 microns, and the thickness of the silicone film layer is 50-80 microns.

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