Preparation method of high-strength wear-resistant silver-based electric contact coating material on metal surface

Abstract

The application discloses a preparation method of a high-strength wear-resistant silver-based electric contact coating material on a metal surface, relates to the technical field of metal surface coating, and prepares a silver metal coating with controllable hardness and thickness and excellent wear resistance through a reaction spray deposition technology. A high-pressure sprayer atomizes liquid through high pressure to obtain micro-nano level mist droplets, the spraying flow and air pressure are adjusted, the high-pressure gas enables the mist droplets to have certain kinetic energy, the silver coating is gradually formed in the form of layer-by-layer deposition during the spraying process, in the continuous nucleation process of the silver layer, the subsequent mist droplets with high kinetic energy implement a 'hammering' effect on the coating, the high-pressure sprayed liquid droplets continuously hammer the just-deposited micron-level silver layer, so that the hardness of the silver layer is improved, and the wear resistance of the silver metal coating is improved; the application realizes the preparation of the silver coating with good conductivity, controllable hardness and high wear resistance, and solves the problems of low hardness and poor wear resistance of the metal surface.

Description

Technical Field

[0001] This invention relates to the field of metal surface coating technology, and in particular to a method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces. Background Technology

[0002] Currently, the most widely used precious metal-based electrical contact materials are silver, gold, platinum, and palladium alloys, as well as composite materials and precious metal coatings made from these alloys. Silver-based electrical contact materials are the most important and widely used precious metal-based electrical contact materials, and they are widely used as the main conductive contact materials in relays, contactors, load switches, medium and low voltage circuit breakers, and switching devices such as household appliances and automotive electrical systems.

[0003] Silver exhibits outstanding advantages in electrical conductivity, processability, and thermal conductivity, but its shortcomings are also significant. Silver has low hardness, low strength, poor wear resistance, and is prone to adhesion. Furthermore, current usage conditions are extremely harsh, making it difficult for ordinary silver electrical contact materials to operate for extended periods in extreme environments. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, the present invention aims to provide a method for preparing a wear-resistant silver-based metal coating with controllable thickness and hardness. This primarily solves the problems of low hardness and poor wear resistance in silver-based coatings.

[0005] To address the aforementioned technical shortcomings, the present invention is implemented through the following technical solution:

[0006] A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces includes the following steps:

[0007] A silver coating with controllable hardness and excellent wear resistance was prepared on a copper substrate using reactive spray deposition technology.

[0008] Step 1: Perform surface pretreatment on the copper surface;

[0009] The substrate surface is ground and polished, and rust is removed using 800-2500 grit sandpaper. Then, it is ultrasonically treated with alcohol and dried at room temperature for later use.

[0010] Step 2: Prepare a mixed solution of the main salt and the reducing agent;

[0011] Silver ammonia solution is prepared by adding ammonium complex to silver nitrate solution until it becomes clear. The ammonium complex includes ammonia water (NH3·H2O), ammonium chloride (NH4Cl), etc. The reducing agent solution is glucose (C6H12O6), potassium sodium tartrate (KNaC4H4O6·4H2O), formaldehyde (HCOH), a mixed solution of glyoxal and triethanolamine, etc.

[0012] Step 3: Prepare a silver metal coating using reactive spray deposition technology;

[0013] By combining a high-pressure sprayer and a spin coater, a reactive spray deposition technique is applied to the polished copper surface to prepare a silver metal coating with controllable hardness and excellent wear resistance.

[0014] Further, prepare a silver ammonia solution by adding dilute ammonia dropwise to the silver nitrate solution in a beaker until the precipitate just dissolves and the overall solution becomes clear.

[0015] Furthermore, in step 1, the metal matrix can be any of the common metals such as copper and its alloys, iron and its alloys.

[0016] Further, step 2 specifically involves: the concentration of silver nitrate being 0.01–0.3 mol / L.

[0017] Further, step 2 specifically involves: a glyoxal concentration of 10–100 ml / L and a triethanolamine concentration of 1–40 ml / L.

[0018] Furthermore, in step 3: the high-pressure sprayer is an internal mixing pneumatic high-pressure atomizer with a gas pressure of 0.1 to 1.5 MPa, an atmosphere type of argon, air, nitrogen, helium, etc., and a nozzle orifice diameter of 0.5 to 3 mm.

[0019] Furthermore, the specific spraying parameters in step 3 are as follows: the distance d between the nozzle and the surface of the metal substrate, the distance between the two nozzles is 2-8 cm, the spraying time is 1-50 min, and the spraying flow rate is 1-40 ml / min.

[0020] Furthermore, in step 3, the spin coater has a rotation speed of 50–200 r / min.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention discloses a method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces. The method utilizes reactive spray deposition technology to prepare a silver metal coating with controllable hardness and thickness and excellent wear resistance. A high-pressure sprayer atomizes liquid into micro-nano-sized droplets. By adjusting the spray flow rate and gas pressure, the high-pressure gas imbues the droplets with kinetic energy, allowing the silver coating to gradually form layer by layer during the spraying process. During this nucleation process, subsequent high-kinetic-energy droplets exert a "forging" effect on the coating. The high-pressure sprayed droplets continuously hammer the newly deposited micron-sized silver layer, increasing its hardness and enhancing its wear resistance. This invention is easy to operate and yields a conductive silver metal coating with controllable thickness and hardness and excellent wear resistance, effectively meeting current requirements in the field of electrical contact materials. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a diagram of the reaction spray experimental apparatus of the present invention.

[0025] Figure 2 This is a microhardness diagram of the silver metal coating in an embodiment of the present invention.

[0026] Figure 3 This is a diagram showing the coefficient of friction for the silver metal coating in an embodiment of the present invention.

[0027] Figure 4 This is a two-dimensional contour diagram of the wear marks in an embodiment of the present invention.

[0028] Figure 5 This is the XRD pattern of the silver coating in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the silver coating microstructure according to an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces, the specific steps of which are as follows:

[0033] Step 1: Surface pretreatment of the copper metal substrate

[0034] (1) Surface polishing: Polish the surface of the copper by using 800-2500 grit sandpaper to remove rust.

[0035] (2) Surface cleaning: Place the polished copper metal substrate in alcohol and sonicate for 5 minutes.

[0036] Step 2: Preparation of silver ammonia solution and reducing agent solution

[0037] Preparation of silver ammonia solution: Silver ammonia solution is prepared by placing 16.9 g / L silver nitrate solution in a 250 ml beaker, adding 2% ammonia water dropwise until clear, wherein the mass of silver nitrate is 1.69 g. A reducing agent is prepared by mixing 50 ml / L glyoxal and 10 ml / L triethanolamine.

[0038] Step 3: Prepare a silver metal coating using reactive spray deposition technology

[0039] (1) Reagent assembly: The silver ammonia solution and the reducing agent are respectively assembled into two high-pressure sprayers.

[0040] (2) Spray deposition parameter settings: air pressure is 0.3MPa, nozzle orifice diameter is 1mm, distance between two nozzles is 4cm, distance between nozzle and metal substrate surface is 5cm, rotation speed is 120r / min, spraying time is 10min, and spraying flow rate is 16ml / min.

[0041] (3) Drying: After taking out the sample, dry it at 80℃ for 1 hour.

[0042] The prepared silver metal coating was characterized by the following tests:

[0043] 1) Cross-sectional view of the silver coating as shown in the figure Figure 2 As shown, the average thickness of the silver coating cross section is 71 μm, and the average Vickers hardness of the silver layer cross section is 118 HV.

[0044] 2) The coefficient of friction for current-carrying silver coating is shown in the figure. Figure 3 As shown, the average coefficient of friction is 0.31.

[0045] 3) Two-dimensional contour diagram of silver coating wear marks, as shown below Figure 4 As shown, the maximum depth of the wear mark is 36.6 mm.

[0046] 4) XRD pattern of silver coating as shown Figure 5 As shown, the average grain diameter of the coating is 40.22 nm.

[0047] Example 2

[0048] A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces, the specific steps of which are as follows:

[0049] Step 1: Surface pretreatment of the copper metal substrate

[0050] (1) Surface polishing: Polish the surface of the copper by using 800-2500 grit sandpaper to remove rust.

[0051] (2) Surface cleaning: Place the polished copper metal substrate in alcohol and perform ultrasonic cleaning for 5 minutes.

[0052] Step 2: Preparation of silver ammonia solution and reducing agent solution

[0053] Preparation of silver ammonia solution: Silver ammonia solution is prepared by placing 16.9 g / L silver nitrate solution in a 250 ml beaker, adding 2% ammonia water dropwise until clear, wherein the mass of silver nitrate is 1.69 g. A reducing agent is prepared by mixing 40 ml / L glyoxal and 20 ml / L triethanolamine.

[0054] Step 3: Prepare a silver metal coating using reactive spray deposition technology

[0055] (1) Reagent assembly: The silver ammonia solution and the reducing agent are respectively assembled into two high-pressure sprayers.

[0056] (2) Spray deposition parameter settings: air pressure is 0.7MPa, nozzle orifice diameter is 1mm, distance between two nozzles is 4cm, distance between nozzle and metal substrate surface is 5cm, rotation speed is 120r / min, spraying time is 10min, and spraying flow rate is 16ml / min.

[0057] (3) Drying: After taking out the sample, dry it at 80℃ for 1 hour.

[0058] The prepared silver metal coating was characterized by the following tests:

[0059] 1) The cross-sectional view of the silver coating is similar. Figure 2 As shown, the average thickness of the silver coating cross section is 90 μm, and the average Vickers hardness of the silver layer cross section is 157 HV.

[0060] 2) The coefficient of friction for current-carrying silver coatings is similar. Figure 3 As shown, the average coefficient of friction is 0.17.

[0061] 3) Similar to the two-dimensional contour diagram of silver coating wear marks Figure 4 As shown, the maximum depth of the wear mark is 24.2 mm.

[0062] 4) The XRD pattern of the silver coating is similar. Figure 5 As shown, the average grain diameter of the coating is 23.06 nm.

[0063] Example 3

[0064] A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces, the specific steps of which are as follows:

[0065] Step 1: Surface pretreatment of the copper metal substrate

[0066] (1) Surface polishing: Polish the surface of the copper by using 800-2500 grit sandpaper to remove rust.

[0067] (2) Surface cleaning: Place the polished copper metal substrate in alcohol and perform ultrasonic cleaning for 5 minutes.

[0068] Step 2: Preparation of silver ammonia solution and reducing agent solution

[0069] Preparation of silver ammonia solution: Silver ammonia solution is prepared by placing 16.9 g / L silver nitrate solution in a 250 ml beaker, adding 2% ammonia water dropwise until clear, wherein the mass of silver nitrate is 1.69 g. A reducing agent is prepared by mixing 10 ml / L glyoxal and 1 ml / L triethanolamine.

[0070] Step 3: Prepare a silver metal coating using reactive spray deposition technology

[0071] (1) Reagent assembly: The silver ammonia solution and the reducing agent are respectively assembled into two high-pressure sprayers.

[0072] (2) Spray deposition parameter settings: air pressure is 0.7MPa, nozzle orifice diameter is 1mm, distance between two nozzles is 4cm, distance between nozzle and metal substrate surface is 5cm, rotation speed is 120r / min, spraying time is 10min, and spraying flow rate is 16ml / min.

[0073] (3) Drying: After taking out the sample, dry it at 80℃ for 1 hour.

[0074] The prepared silver metal coating was characterized by the following tests:

[0075] 1) The cross-sectional view of the silver coating is similar. Figure 2 As shown, the average thickness of the silver coating cross section is 28 μm, and the average Vickers hardness of the silver layer cross section is 37 HV.

[0076] 2) The coefficient of friction for current-carrying silver coatings is similar. Figure 3 As shown, the average coefficient of friction is 0.45.

[0077] 3) Similar to the two-dimensional contour diagram of silver coating wear marks Figure 4 As shown, the maximum depth of the wear mark is 64.5 mm.

[0078] 4) The XRD pattern of the silver coating is similar. Figure 5 As shown, the average grain diameter of the coating is 69.06 nm.

[0079] Example 4

[0080] A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces, the specific steps of which are as follows:

[0081] Step 1: Surface pretreatment of the copper metal substrate

[0082] (1) Surface polishing: Polish the surface of the copper by using 800-2500 grit sandpaper to remove rust.

[0083] (2) Surface cleaning: Place the polished copper metal substrate in alcohol and perform ultrasonic cleaning for 5 minutes.

[0084] Step 2: Preparation of silver ammonia solution and reducing agent solution

[0085] Preparation of silver ammonia solution: Silver ammonia solution is prepared by placing 16.9 g / L silver nitrate solution in a 250 ml beaker, adding 2% ammonia water dropwise until clear, wherein the mass of silver nitrate is 1.69 g. A reducing agent is prepared by mixing 60 ml / L glyoxal and 5 ml / L triethanolamine.

[0086] Step 3: Prepare a silver metal coating using reactive spray deposition technology

[0087] (1) Reagent assembly: The silver ammonia solution and the reducing agent are respectively assembled into two high-pressure sprayers.

[0088] (2) Spray deposition parameter settings: air pressure is 1.2MPa, nozzle orifice diameter is 1mm, distance between two nozzles is 4cm, distance between nozzle and metal substrate surface is 5cm, rotation speed is 120r / min, spraying time is 10min, and spraying flow rate is 16ml / min.

[0089] (3) Drying: After taking out the sample, dry it at 80℃ for 1 hour.

[0090] The prepared silver metal coating was characterized by the following tests:

[0091] 1) The cross-sectional view of the silver coating is similar. Figure 2 As shown, the average thickness of the silver coating cross section is 47 μm, and the average Vickers hardness of the silver layer cross section is 85 HV.

[0092] 2) The coefficient of friction for current-carrying silver coatings is similar. Figure 3 As shown, the average coefficient of friction is 0.42.

[0093] 3) Similar to the two-dimensional contour diagram of silver coating wear marks Figure 4 As shown, the maximum depth of the wear mark is 41.2 mm.

[0094] 4) The XRD pattern of the silver coating is similar. Figure 5 As shown, the average grain diameter of the coating is 35.46 nm.

[0095] Comparative Examples

[0096] A method for preparing a silver-based coating on a metal surface, the specific operation steps of which are as follows:

[0097] Step 1: Surface pretreatment of the copper metal substrate

[0098] (1) Surface polishing: Polish the surface of the copper by using 800-2500 grit sandpaper to remove rust.

[0099] (2) Surface cleaning: Place the polished copper metal substrate in alcohol and perform ultrasonic cleaning for 5 minutes.

[0100] Step 2: Preparation of silver ammonia solution and reducing agent solution

[0101] Preparation of silver ammonia solution: Silver ammonia solution is prepared by placing 16.9 g / L silver nitrate solution in a 250 ml beaker, adding 2% ammonia water dropwise until clear, wherein the mass of silver nitrate is 1.69 g. A reducing agent is prepared by mixing 100 ml / L glyoxal and 20 ml / L triethanolamine.

[0102] Step 3: Prepare a silver metal coating using reactive spray deposition technology

[0103] (1) Reagent assembly: The silver ammonia solution and the reducing agent are respectively assembled into two high-pressure sprayers.

[0104] (2) Spray deposition parameter settings: air pressure is 0.1MPa, nozzle orifice diameter is 1mm, distance between two nozzles is 4cm, distance between nozzle and metal substrate surface is 5cm, rotation speed is 120r / min, spraying time is 10min, and spraying flow rate is 16ml / min.

[0105] (3) Drying: After taking out the sample, dry it at 80℃ for 1 hour.

[0106] The prepared silver metal coating was characterized by the following tests:

[0107] 1) The cross-sectional view of the silver coating is similar. Figure 2 As shown, the average thickness of the silver coating cross section is 32 μm, and the average Vickers hardness of the silver layer cross section is 45 HV.

[0108] 2) The coefficient of friction for current-carrying silver coatings is similar. Figure 3 As shown, the average coefficient of friction is 0.49.

[0109] 3) Similar to the two-dimensional contour diagram of silver coating wear marks Figure 4 As shown, the maximum depth of the wear marks is 69.4 mm.

[0110] 4) The XRD pattern of the silver coating is similar. Figure 5 As shown, the average grain diameter of the coating is 72.31 nm.

[0111] Compared with existing technologies, the beneficial effects of this invention are as follows:

[0112] This invention discloses a method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces. The method utilizes reactive spray deposition technology to prepare a silver metal coating with controllable hardness and thickness and excellent wear resistance. A high-pressure sprayer atomizes liquid into micro-nano-sized droplets. By adjusting the spray flow rate and gas pressure, the high-pressure gas imbues the droplets with kinetic energy, allowing the silver coating to gradually form layer by layer during the spraying process. During this nucleation process, subsequent high-energy droplets exert a "forging" effect on the coating. The high-pressure sprayed droplets continuously hammer the newly deposited micron-sized silver layer, increasing its hardness and enhancing its wear resistance. This invention is easy to operate and yields a conductive silver metal coating with controllable thickness and hardness and excellent wear resistance, effectively meeting current requirements in the field of electrical contact materials.

[0113] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces, characterized in that, Includes the following steps: Step 1: Perform surface rust removal and surface cleaning on the metal surface; Use 800~2500 grit sandpaper to remove rust and polish the metal surface, then ultrasonically clean it with alcohol, and blow it dry at room temperature for later use. Step 2: Prepare silver ammonia solution and reducing agent; The silver ammonia solution is prepared by adding ammonia dropwise to silver nitrate solution until it becomes clear. The concentration of the silver ammonia solution is 0.01~0.3 mol / L, and the concentration of silver nitrate is 0.01~0.3 mol / L. The reducing agent consists of glyoxal, triethanolamine and deionized water, wherein the volume fraction ratio of glyoxal to triethanolamine is 1~6:

1. Step 3: Prepare a silver metal coating using reactive spray deposition technology; the silver ammonia solution and reducing agent solution prepared in Step 2 are respectively assembled into two high-pressure sprayers, and the silver metal coating is prepared by adjusting the spray flow rate, spray distance, spray time, spray pressure and turntable speed; the high-pressure atomization spraying process is specifically as follows: the spray distance is 3~9cm, the distance between the two nozzles is 2~8cm, the spray flow rate is 1~40ml / min, the spray time is 1~50min, and the rotation speed is 50~200r / min; the gas atmosphere in the reactive spray deposition process is one of argon, air, nitrogen and helium, the gas pressure is 0.1~1.5MPa, and the nozzle orifice diameter is 0.5~3mm.

2. The method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces according to claim 1, characterized in that: The metal is one of copper, copper alloy, nickel, or iron.

3. The method for preparing a high-strength, wear-resistant silver-based electrical contact coating material for metal surfaces according to claim 1, characterized in that: In step 2, the concentration of glyoxal is 10~100 ml / L and the concentration of triethanolamine is 1~40 ml / L.

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