Nickel-ruthenium composite coating plating method for molybdenum alloy substrate

Abstract

The invention relates to a nickel-ruthenium composite coating plating method for a molybdenum alloy substrate, which is applied to the field of processing and manufacturing of metal-based molybdenum alloy substrates and comprises the following steps: carrying out surface pretreatment on a molybdenum sheet raw material to obtain a net molybdenum sheet; putting the pure molybdenum sheet into vacuum coating equipment, and starting the vacuum coating equipment to vacuumize to form a vacuum system; and vacuum coating equipment is started for heating, a high-temperature system is formed, the surface of the net molybdenum sheet is coated with a physical vapor deposition method, and the molybdenum sheet with nickel plated on the two faces and ruthenium plated on the single face is obtained. The method has the technical effects that a good coating film is formed on the surface of the molybdenum sheet through a vacuum coating method, the method is green and environmentally friendly, harmful substances are reduced, the adhesive force between the coating layer and the molybdenum sheet is high, the film layer is high in purity and good in quality, and the production quality of the molybdenum alloy substrate is improved. Grease, oxides, residual solvents, impurities and the like on the surface of the molybdenum sheet are cleaned through the surface pretreatment step, the surface quality and binding force of the molybdenum sheet are improved, and the connection firmness of the nickel-ruthenium composite coating on the surface of the molybdenum sheet is improved.

Description

Technical Field

[0001] The present application relates to the technical field of processing and manufacturing of metal-based molybdenum alloy substrates, and in particular to a method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate. Background Art

[0002] Molybdenum alloy substrates are used as heat dissipation packaging materials for IGBT modules. IGBT modules are core devices for energy conversion and transmission. The production and manufacturing requirements of molybdenum alloy substrates are constantly developing towards higher requirements and standards as the devices develop.

[0003] During the production process, the surface of the molybdenum sheet needs to be nickel-plated. In conventional production, chemical plating is usually used. Chemical plating is a plating method that uses a suitable reducing agent without an external current to reduce the metal ions in the plating solution to metal and deposit them on the surface of the part.

[0004] The above-mentioned related technologies use chemical plating to plate nickel, which causes serious environmental pollution and poor stability of the coating, resulting in low production quality of the molybdenum alloy substrate. Summary of the invention

[0005] In order to help solve the problem that the nickel plating method of chemical plating causes serious environmental pollution and poor coating stability, resulting in low production quality of molybdenum alloy substrates, the present application provides a method for nickel-ruthenium composite plating of molybdenum alloy substrates, which adopts the following technical scheme: surface pretreatment of the molybdenum sheet raw material is performed to obtain a clean molybdenum sheet; the clean molybdenum sheet is placed in a vacuum coating device, and the vacuum coating device is started to evacuate to form a vacuum system; the vacuum coating device is started to heat to form a high-temperature system, and the surface of the clean molybdenum sheet is nickel-plated by physical vapor deposition to obtain a single-sided nickel-plated molybdenum sheet; the single-sided nickel-plated molybdenum sheet is taken out and turned over, the single-sided nickel-plated molybdenum sheet is placed in a vacuum coating device, and the vacuum coating device is started to evacuate to form a vacuum system; starting the vacuum coating equipment for heating to form a high-temperature system, using physical vapor deposition to perform secondary nickel plating on the non-nickel-plated surface of the single-sided nickel-plated molybdenum sheet to obtain a double-sided nickel-plated molybdenum sheet; placing the double-sided nickel-plated molybdenum sheet in an annealing furnace for high-temperature annealing to release the stress of the nickel-plated layer, and forming an alloy layer between the nickel and molybdenum bonding layers; placing the annealed double-sided nickel-plated molybdenum sheet into the vacuum coating equipment, starting the vacuum coating equipment to evacuate to form a vacuum system, applying RF current to the annealed double-sided nickel-plated molybdenum sheet, and ion cleaning the surface of the annealed double-sided nickel-plated molybdenum sheet; taking out the double-sided nickel-plated molybdenum sheet after ion cleaning, and using physical vapor deposition to plate ruthenium on one side of the double-sided nickel-plated molybdenum sheet to obtain a double-sided nickel-plated and single-sided ruthenium-plated molybdenum sheet.

[0006] In a specific possible implementation plan, the surface pretreatment step includes: placing the molybdenum sheet raw material into a first solution for electrolytic degreasing reaction, the first solution is used to remove grease on the surface of the molybdenum sheet raw material, and taking out the reacted molybdenum sheet raw material for rinsing; placing the rinsed molybdenum sheet raw material into a second solution for soaking for a preset time, the second solution is used to remove oxides on the surface of the molybdenum sheet raw material; taking out the soaked molybdenum sheet raw material and placing it into a cleaning device for cleaning, the cleaning device is used to clean the residual solution on the surface of the molybdenum sheet; taking out the cleaned molybdenum sheet raw material, using a third solution for a second cleaning and then drying to obtain a clean molybdenum sheet.

[0007] In a specific embodiment, the first solution comprises sodium hydroxide and sodium carbonate, wherein the concentration of sodium hydroxide in the first solution is 10-20 g / L, and the concentration of sodium carbonate in the first solution is 20-30 g / L.

[0008] In a specific embodiment, the second solution comprises hydrochloric acid, sulfuric acid and water, wherein the mass ratio of hydrochloric acid, sulfuric acid and water is 3:3:14.

[0009] In a specific implementation scheme, the cleaning device uses an ultrasonic device, wherein the ultrasonic device uses pure water as a cleaning agent, and the parameters of the ultrasonic device include a temperature of 58 to 61° C., a current of 3A, and a cleaning time of 5 to 8 minutes.

[0010] In a specific embodiment, the third solution is pure water.

[0011] In a specific embodiment, the vacuum degree of the high vacuum is 0.0005Pa.

[0012] In a specific embodiment, the temperature of the high temperature system is 98-102°C.

[0013] In a specific possible implementation manner, the physical vapor deposition method adopts a vacuum coating method, and the vacuum coating method specifically adopts magnetron sputtering coating.

[0014] In a specific implementation scheme, the temperature of the high temperature annealing is 580-620° C., the ion cleaning time is 5-8 minutes, the medium gas of the ion cleaning is 99.999% high-purity argon gas, and the gas flow rate of the high-purity argon gas is 200 sccm.

[0015] In summary, this application has at least the following beneficial technical effects:

[0016] 1. The problem of serious pollution and poor coating stability caused by chemical nickel plating in the related art is solved. The present application forms a good coating on the surface of the molybdenum sheet by vacuum coating, which is green and environmentally friendly and reduces the generation of harmful substances. The coating has strong adhesion to the molybdenum sheet, and the film layer has high purity and quality, thereby improving the production quality of the molybdenum alloy substrate.

[0017] 2. The surface pretreatment step is used to clean the grease, oxides, residual solvents and impurities on the surface of the molybdenum sheet, thereby improving the surface quality and bonding strength of the molybdenum sheet, thereby improving the connection firmness of the molybdenum-nickel alloy layer on the surface of the molybdenum sheet. DETAILED DESCRIPTION

[0018] The embodiment of the present application discloses a method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate.

[0019] The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate comprises:

[0020] S10, performing surface pretreatment on the molybdenum sheet raw material to obtain a clean molybdenum sheet. It should be noted that the surface pretreatment in S10 includes the following steps:

[0021] S11, placing the molybdenum sheet raw material into the first solution for removing grease from the surface of the molybdenum sheet raw material for electrolytic degreasing reaction, preferably the temperature of the electrolytic degreasing reaction can be 70° C., the reaction time is 5 minutes, and the current density is 50 mA / cm 2 In the embodiment of the present application, the first solution comprises sodium hydroxide and sodium carbonate, wherein the concentration of sodium hydroxide in the first solution is 10-20 g / L, and the concentration of sodium carbonate in the first solution is 20-30 g / L. The operator adds sodium hydroxide to the sodium carbonate solution and stirs it evenly to obtain the first solution.

[0022] S12, taking out the molybdenum sheet raw material after the electrolytic degreasing reaction and rinsing it with pure water until there is no obvious solution residue on the surface.

[0023] S13, placing the molybdenum sheet raw material after rinsing with pure water into a second solution for removing oxides on the surface of the molybdenum sheet raw material and soaking it for a preset time. In the embodiment of the present application, the soaking time is preset to 20 seconds. The second solution contains hydrochloric acid, sulfuric acid and water, wherein the mass ratio of hydrochloric acid, sulfuric acid and water is 3:3:14.

[0024] S14, taking out the molybdenum sheet raw material after soaking for a preset time and putting it into a cleaning device for cleaning to remove the residual solution on the surface of the molybdenum sheet. In the embodiment of the present application, the cleaning device adopts an ultrasonic device, wherein the ultrasonic device adopts pure water as a cleaning agent. The parameters of the ultrasonic device are as follows: the current is 3A; the temperature is 58-61°C, and the temperature can be set to 58°C, 60°C or 61°C, wherein 60°C is the optimal temperature; the cleaning time is 5-8 minutes, and the cleaning time of the ultrasonic device in the embodiment of the present application is 5 minutes.

[0025] S15, taking out the molybdenum sheet raw material after ultrasonic cleaning, using a third solution to perform secondary cleaning on the molybdenum sheet raw material and then drying it, the third solution using pure water, so as to obtain a clean molybdenum sheet. In the embodiment of the present application, the clean molybdenum sheet is a clean molybdenum sheet, and there is no obvious impurities and no obvious reagent residue on the surface of the clean molybdenum sheet, which improves the surface quality and bonding strength of the molybdenum sheet, thereby improving the connection firmness of the molybdenum-nickel alloy layer on the surface of the molybdenum sheet.

[0026] S20, placing the clean molybdenum sheet into a vacuum coating device, the vacuum coating device in the embodiment of the present application can be a vacuum coating machine, and starting the vacuum coating device to evacuate the vacuum to a vacuum degree of 0.0005 Pa, thereby forming a vacuum system.

[0027] S30, start the vacuum coating equipment to heat up, and heat up to form a high-temperature system. The temperature of the high-temperature system is 98-102°C. In the embodiment of the present application, the temperature of the high-temperature system is 100°C. Subsequently, the surface of the clean molybdenum sheet is nickel-plated by physical vapor deposition, wherein the physical vapor deposition method adopts a vacuum coating method, and the vacuum coating method specifically adopts magnetron sputtering coating. After the ruthenium plating is completed, the temperature is lowered to obtain a single-sided nickel-plated molybdenum sheet. Magnetron sputtering coating technology has a high coating speed. The film obtained by sputtering has high purity, good density, and good film uniformity. The film is firmly combined with the clean molybdenum sheet, which increases the wear resistance and scratch resistance of the molybdenum alloy substrate. In the embodiment of the present application, the nickel plating process is to set the power of the vacuum coating equipment to 1000W, the air pressure to 0.4Pa, and the nickel plating time to 35min.

[0028] S40, taking out the single-sided nickel-plated molybdenum sheet and turning it over, placing the single-sided nickel-plated molybdenum sheet with the uncoated surface facing upward into a vacuum coating device, starting the vacuum coating device to evacuate the sheet, and the vacuum degree of the evacuation is 0.0005 Pa, thereby forming a vacuum system.

[0029] S50, start the vacuum coating equipment to heat and form a high temperature system. In the embodiment of the present application, the temperature of the high temperature system is 100°C. Then, the non-nickel-plated surface of the single-sided nickel-plated molybdenum sheet is subjected to secondary nickel plating by physical vapor deposition. After the ruthenium plating is completed, the double-sided nickel-plated molybdenum sheet is obtained by cooling. In the embodiment of the present application, the nickel plating process is to set the power of the vacuum coating equipment to 1000W, the air pressure to 0.4Pa, and the nickel plating time to 35min.

[0030] S60, placing the double-sided nickel-plated molybdenum sheet in an annealing furnace for high-temperature annealing. In the embodiment of the present application, the temperature of high-temperature annealing is 600° C., so as to release the stress of the nickel-plated layer, form an alloy layer with the nickel and molybdenum bonding layer, and improve the bonding force between the nickel and the surface of the molybdenum sheet.

[0031] S70, placing the annealed double-sided nickel-plated molybdenum sheet into the vacuum coating equipment, starting the vacuum coating equipment to evacuate, forming a vacuum system, applying RF current to the annealed double-sided nickel-plated molybdenum sheet, and realizing ion cleaning of the surface of the annealed double-sided nickel-plated molybdenum sheet. In the embodiment of the present application, the power of the vacuum coating equipment is set to 1000W, the ion cleaning time is 5 minutes, the medium gas for ion cleaning is 99.999% high-purity argon gas, and the gas flow rate of the high-purity argon gas is 200sccm, thereby cleaning the oxide layer on the surface of the nickel layer, laying the foundation for the next step of ruthenium plating and the bonding of the ruthenium nickel layer.

[0032] S80, take out the double-sided nickel-plated molybdenum sheet after ion cleaning, and finally use physical vapor deposition to plate ruthenium on one side of the double-sided nickel-plated molybdenum sheet. After the ruthenium plating is completed, the double-sided nickel-plated and single-sided ruthenium-plated molybdenum sheet is obtained by cooling. In the embodiment of the present application, the ruthenium plating process is to set the power of the vacuum coating equipment to 2000W, the air pressure to 0.5Pa, and the ruthenium plating time to 8min.

[0033] In addition, since nickel is a magnetic material, magnetron sputtering nickel plating has a higher difficulty than the magnetron sputtering ruthenium plating and silver plating processes in the related art. During the sputtering film forming process, the stress will show a straight-line upward trend, and the film layer bonding force is poor. Following the existing magnetron sputtering process, the coating thickness is 1.15um, while the process of the molybdenum alloy substrate in this application requires the nickel plating thickness to be 3um, and the thickness doubles, resulting in an increase in its stress. The process in the prior art is difficult to meet the processing requirements of thick nickel. Conventional molybdenum sheet surface nickel plating is carried out by electroplating, and its process is relatively stable, but due to the reasons of electroplating itself, the current effect of electroplating is more serious, the edge coating thickness of the product is often one to two times the middle thickness, and the overall coating uniformity is poor; at the same time, electroplating thick nickel often requires first plating a thin layer of nickel and then annealing the alloy, followed by thick nickel plating, and the process is complicated and there are many uncontrollable factors; in addition, the electroplating film plating method has a greater impact on the environment, with more pollutants, which does not meet the current green and environmentally friendly production theme. The magnetron sputtering vacuum coating method is relatively simple, with fixed and controllable parameters, and the film thickness deviation can be controlled within 10%, with good consistency. At the same time, this method is the main green coating method currently developed and is environmentally friendly.

[0034] At the same time, a nickel-ruthenium composite coating is used to replace the ruthenium-silver composite coating in the related technology, and the requirements for the process are also more stringent. In order to improve the welding quality of the nickel layer surface, this application uses vacuum coating to plate nickel on the surface of the clean molybdenum sheet, and adopts a low-power rapid film-forming process to effectively reduce stress. At the same time, the film-forming process is simple, the nickel plating has good uniformity and high stability, and it effectively saves production time and improves production efficiency in view of the production requirements of thick nickel and composite ruthenium plating. At the same time, a high-temperature annealing method is used for the nickel layer to improve the bonding strength of nickel and molybdenum; an RF power ion cleaning method is used to improve the surface cleanliness of the nickel layer and improve the bonding strength of the nickel and ruthenium layers.

[0035] The implementation principle of the embodiment of the present application is as follows: the surface of the molybdenum sheet raw material is pretreated and dried to obtain a clean molybdenum sheet; the clean molybdenum sheet is placed in a vacuum coating device for evacuation to form a vacuum system; the vacuum coating device is heated to form a high-temperature system, and then nickel is plated by a vacuum coating method, and after the nickel plating is completed, the temperature is lowered to obtain a single-sided nickel-plated molybdenum sheet; the single-sided nickel-plated molybdenum sheet is taken out, turned over, and put back into the vacuum coating device, and evacuation is formed into a vacuum system; the vacuum ruthenium plating device is heated to form a high-temperature system, and then nickel is plated for the second time by the vacuum coating method, and ... After heating, a double-sided nickel-plated molybdenum sheet is obtained; the double-sided nickel-plated molybdenum sheet is placed in an annealing furnace for high-temperature annealing; the annealed double-sided nickel-plated molybdenum sheet is placed in a vacuum coating device, the vacuum coating device is started to evacuate to form a vacuum system, RF current is applied to the annealed double-sided nickel-plated molybdenum sheet, and the surface of the annealed double-sided nickel-plated molybdenum sheet is ion-cleaned; the double-sided nickel-plated molybdenum sheet after ion cleaning is taken out, and then ruthenium is plated by a vacuum coating method, and a double-sided nickel-plated and single-sided ruthenium-plated molybdenum sheet is obtained after cooling, and the double-sided nickel-plated and single-sided ruthenium-plated molybdenum sheet is taken out from the vacuum ruthenium plating device.

[0036] The present application adopts a surface pretreatment step to clean the grease, oxides, residual solvents and impurities on the surface of the molybdenum sheet, thereby improving the surface quality and bonding strength of the molybdenum sheet, thereby improving the connection firmness of the molybdenum-nickel alloy layer on the surface of the molybdenum sheet. The nickel-ruthenium composite coating method of the molybdenum alloy substrate solves the problem of serious pollution and poor coating stability caused by the chemical nickel plating operation in the related art. The present application forms a good coating on the surface of the molybdenum sheet through a vacuum coating method, which is green and environmentally friendly and reduces the generation of harmful substances. The coating has strong adhesion to the molybdenum sheet, and the film layer has high purity and quality, thereby improving the production quality of the molybdenum alloy substrate.

[0037] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate, characterized in that: The molybdenum sheet raw material is subjected to surface pretreatment to obtain a clean molybdenum sheet; Place the clean molybdenum sheet into the vacuum coating equipment, start the vacuum coating equipment to evacuate, and form a vacuum system; The vacuum coating equipment is started to heat up to form a high temperature system, and the surface of the clean molybdenum sheet is nickel plated by physical vapor deposition to obtain a single-sided nickel-plated molybdenum sheet; Take out the single-sided nickel-plated molybdenum sheet and turn it over, put the single-sided nickel-plated molybdenum sheet into a vacuum coating device, start the vacuum coating device to evacuate, and form a vacuum system; The vacuum coating equipment is started to heat up to form a high temperature system, and the unnickel-plated surface of the single-sided nickel-plated molybdenum sheet is subjected to secondary nickel plating by physical vapor deposition to obtain a double-sided nickel-plated molybdenum sheet; The double-sided nickel-plated molybdenum sheet is placed in an annealing furnace for high-temperature annealing to release the stress of the nickel-plated layer and form an alloy layer with the nickel and molybdenum bonding layers; The annealed double-sided nickel-plated molybdenum sheet is placed in a vacuum coating device, the vacuum coating device is started to evacuate the sheet to form a vacuum system, an RF current is applied to the annealed double-sided nickel-plated molybdenum sheet, and the surface of the annealed double-sided nickel-plated molybdenum sheet is ion-cleaned; The double-sided nickel-plated molybdenum sheet after ion cleaning is taken out, and one side of the double-sided nickel-plated molybdenum sheet is plated with ruthenium by using a physical vapor deposition method to obtain a double-sided nickel-plated and single-sided ruthenium-plated molybdenum sheet.

2. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 1, characterized in that: The surface pretreatment step comprises: Placing the molybdenum sheet raw material into a first solution for electrolytic degreasing reaction, wherein the first solution is used to remove grease on the surface of the molybdenum sheet raw material, and taking out the molybdenum sheet raw material after the reaction and washing it; Putting the rinsed molybdenum sheet raw material into a second solution and soaking it for a preset time, wherein the second solution is used to remove oxides on the surface of the molybdenum sheet raw material; The molybdenum sheet raw material after soaking is taken out and put into a cleaning device for cleaning, wherein the cleaning device is used to clean the residual solution on the surface of the molybdenum sheet; The cleaned molybdenum sheet raw material is taken out, and is cleaned twice with the third solution and then dried to obtain a clean molybdenum sheet.

3. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 2, characterized in that: The first solution comprises sodium hydroxide and sodium carbonate, wherein the concentration of sodium hydroxide in the first solution is 10-20 g / L, and the concentration of sodium carbonate in the first solution is 20-30 g / L.

4. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 2, characterized in that: The second solution comprises hydrochloric acid, sulfuric acid and water, wherein the mass ratio of hydrochloric acid, sulfuric acid and water is 3:3:

14.

5. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 2, characterized in that: The cleaning equipment adopts an ultrasonic device, wherein the ultrasonic device adopts pure water as a cleaning agent, and the parameters of the ultrasonic device include a temperature of 58 to 61° C., a current of 3A, and a cleaning time of 5 to 8 minutes.

6. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 2, characterized in that: The third solution is pure water.

7. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 1, characterized in that: The vacuum degree of the vacuum pumping is 0.0005Pa.

8. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 1, characterized in that: The temperature of the high temperature system is 98-102°C.

9. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 1, characterized in that: The physical vapor deposition method adopts a vacuum coating method, and the vacuum coating method specifically adopts magnetron sputtering coating.

10. The method for plating a nickel-ruthenium composite coating on a molybdenum alloy substrate according to claim 1, characterized in that: The temperature of the high temperature annealing is 580-620° C., the time of the ion cleaning is 5-8 minutes, the medium gas of the ion cleaning is 99.999% high-purity argon gas, and the gas flow rate of the high-purity argon gas is 200 sccm.