Process for electroplating platinum coating on titanium felt base material

Abstract

The invention relates to the technical field of material surface treatment, and discloses a process for electroplating a platinum coating on a titanium felt base material, the process is particularly suitable for constructing the platinum coating with specific performance on the surface of a titanium felt, meanwhile, a tin-antimony coating is used as a middle layer for bottoming so as to improve the adhesive force and the overall performance of the coating, and the process comprises the following steps that 1, the platinum coating is prepared, pretreating the titanium felt; step 2, preparing a tin-antimony coating; and step 3, electroplating the platinum coating. According to the process method, the adhesive force can be obviously improved, the uniformity of the coating is ensured, and the comprehensive performance is obviously improved.

Description

Technical Field

[0001] The present application relates to the technical field of material surface treatment, and more particularly, to a process for electroplating a platinum coating on a titanium felt substrate. Background Art

[0002] Hydrogen energy, as a new generation of renewable green energy, has garnered widespread attention, and hydrogen production technology is crucial for its development. Proton exchange membrane water electrolysis (PEMWE) has attracted widespread attention in the hydrogen energy field due to its advantages, including high hydrogen production rates, fast start-stop times, and high energy efficiency. Under the acidic, oxygen-rich, and highly polarized operating environment of the PEMWE anode, a high-performance platinum-coated gas diffusion layer (platinum-coated titanium felt) is designed to enhance the corrosion resistance, conductivity, hydrophilicity, and stability of the titanium-based porous transport layer, providing insights for promoting the industrial application of water electrolysis hydrogen production technology.

[0003] Titanium felt, due to its uniquely high surface area, excellent corrosion resistance, and superior mechanical properties, exhibits enormous application potential in a wide range of fields, including electrochemical catalysis, battery electrodes, and wastewater treatment. Electroplating precious metal coatings on titanium felt is an effective method to further expand its performance. Platinum, with its exceptional catalytic activity, chemical stability, and corrosion resistance, can significantly enhance its performance in related applications by electroplating it on the surface.

[0004] However, there are many problems with directly electroplating platinum on titanium felt. On the one hand, the surface properties of titanium are relatively unique, and the adhesion between platinum and titanium felt is poor. The coating is prone to shedding during use, seriously affecting the service life and performance stability. On the other hand, traditional electroplating processes make it difficult to accurately control the thickness and uniformity of the coating, resulting in uneven product quality. In addition, in some complex application environments, such as high humidity and strong acid and alkali conditions, the lack of an effective intermediate transition layer prevents the platinum coating from fully realizing its performance advantages and may even accelerate failure due to electrochemical corrosion between the substrate and the coating.

[0005] While there are currently several methods for electroplating precious metals on metal surfaces, a process specifically for platinum coating on titanium felt substrates, using a suitable intermediate layer as a primer, is still lacking. Therefore, developing a process that can effectively address these challenges and successfully electroplate a uniform, durable, and high-performance platinum coating on titanium felt surfaces is of great practical significance and market demand. Summary of the Invention

[0006] The present invention aims to provide a process for electroplating a platinum coating on a titanium felt substrate. By first constructing a tin-antimony coating on the titanium felt surface as an intermediate layer for priming, and then electroplating the platinum coating, the adhesion between the platinum coating and the titanium felt substrate is improved, ensuring the uniformity and stability of the coating, thereby enhancing the overall performance of the product in complex environments.

[0007] In order to achieve the above-mentioned object of the invention, the present application provides a process for electroplating a platinum coating on a titanium felt substrate, comprising the following steps: Step 1, titanium felt pretreatment; Step 2, preparation of tin-antimony coating; Step 3: Platinum coating electroplating.

[0008] Furthermore, the step 1 is: Rinse the titanium felt with deionized water to remove dust and loose impurities on the surface; soak the titanium felt in a 5-10% sodium hydroxide solution by mass and ultrasonically clean it at 50-60°C for 10-15 minutes to remove oil stains and part of the oxide film on the surface; rinse the titanium felt repeatedly with deionized water until the rinse water is neutral; Place the cleaned titanium felt in a 10-15% by mass hydrochloric acid solution and soak it at room temperature for 5-10 minutes to further remove the residual oxide film and impurities on the surface. Then rinse it again with deionized water, ultrasonically clean it for 10-15 minutes, rinse it clean and dry it.

[0009] Furthermore, the step 2 is: Preparation of electroplating solution: Weigh stannous chloride and antimony trichloride, with the concentration of stannous chloride controlled at 10-20 g / L and the concentration of antimony trichloride controlled at 5-10 g / L, dissolve them in an aqueous solution containing 15%-25% hydrochloric acid by volume, stir evenly, and prepare an electroplating solution; Electroplating: Use pretreated titanium felt as the cathode and graphite plate as the anode, placing both in the electroplating solution. During electroplating, control the current density to 1-3A / dm², maintain the temperature at 25-35°C, and electroplating for 20-30 minutes. During the electroplating process, use a magnetic stirrer to stir the electroplating solution at a speed of 100-150 rpm to ensure the uniformity of the electroplating solution and promote ion diffusion, thereby obtaining a uniform tin-antimony coating. Post-plating treatment: After the electroplating is completed, the titanium felt coated with tin-antimony coating is removed from the electroplating solution, rinsed with deionized water, and then dried in an oven at 100-120℃ for 1-2 hours to remove residual moisture on the surface and further solidify the tin-antimony coating.

[0010] Furthermore, during the preparation of the electroplating solution, additives including brighteners and levelers are added to improve the quality of the tin-antimony coating.

[0011] Furthermore, the brightener is saccharin sodium with a concentration of 0.5-1 g / L; the leveling agent is polyethylene glycol with a concentration of 1-2 g / L.

[0012] Furthermore, the step 3 is: Preparation of electroplating solution: Use chloroplatinic acid as the main salt, the concentration is controlled at 5-10g / L, and dissolve it in an aqueous solution containing 5-10% sulfuric acid by volume; Electroplating: Place a titanium felt coated with tin-antimony as the cathode and a pure platinum sheet as the anode in a prepared platinum electroplating solution. During electroplating, control the current density to 0.5-1.5A / dm², maintain the temperature at 40-50°C, and electroplating for 30-45 minutes. During the electroplating process, use a magnetic stirrer to stir the electroplating solution at a speed of 80-120 rpm to ensure that the platinum ions are evenly deposited on the surface of the tin-antimony coating, forming a uniform and dense platinum coating. Post-plating treatment: After the electroplating is completed, the titanium felt with platinum coating is removed from the electroplating solution, rinsed with deionized water, and then dried in an oven at 80-100°C for 0.5-1 hour to remove residual moisture on the surface; the platinum coating is passivated by immersing it in a passivation solution containing 2-5% nitric acid by volume for 3-5 minutes at room temperature, then removed, rinsed with deionized water and dried to improve the corrosion resistance of the platinum coating.

[0013] Furthermore, during the preparation of the electroplating solution, additives including stabilizers and accelerators are added to improve the stability of platinum electroplating and the quality of the coating.

[0014] Furthermore, the stabilizer is disodium ethylenediaminetetraacetate, with a concentration of 0.5-1 g / L; the accelerator is butynediol, with a concentration of 0.1-0.3 g / L.

[0015] Furthermore, it also includes step 4 coating inspection, including appearance inspection, thickness inspection, adhesion inspection and product application performance inspection In summary, this application has the following beneficial effects: 1. Improved Adhesion: By introducing a tin-antimony coating as an intermediate layer between the titanium felt substrate and the platinum coating, the adhesion between the platinum coating and the titanium felt is effectively improved. The tin-antimony coating forms a good metallurgical bond with the titanium felt substrate, and its surface properties are conducive to the deposition and adhesion of platinum, significantly reducing the risk of the platinum coating falling off during use and extending the product's service life.

[0016] 2. Ensure coating uniformity: During the electroplating process of tin-antimony and platinum coatings, precise control of process parameters such as the composition of the plating solution, current density, temperature, stirring speed, and plating time allows for effective control of coating thickness and uniformity. This ensures that the prepared platinum and tin-antimony coatings are evenly distributed on the titanium felt surface, avoiding performance differences caused by uneven coatings and improving product quality consistency.

[0017] 3. Improved Overall Performance: The multilayer coating structure prepared by this invention not only fully utilizes the excellent catalytic activity, chemical stability, and corrosion resistance of platinum, but also utilizes the characteristics of the tin-antimony coating to enhance the overall performance of the coating system. In complex application environments, it can effectively resist the influence of factors such as corrosion and wear, ensuring the product maintains stable performance during long-term use, and broadening the application range of titanium felt in high-end fields. DETAILED DESCRIPTION

[0018] The technical solutions and effects of the present application are further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention, rather than to limit the invention.

[0019] Example 1

[0020] This embodiment discloses a process for electroplating a platinum coating on a titanium felt substrate, which specifically includes the following steps: Step 1, titanium felt pretreatment: After rinsing the titanium felt with deionized water, soak it in a 5% sodium hydroxide solution and ultrasonically clean it at 50°C for 10 minutes. Then rinse it with deionized water until it is neutral. Then, place it in a 10% hydrochloric acid solution and soak it at room temperature for 5 minutes. Then, ultrasonically clean it with deionized water for 20 minutes. Finally, rinse it with deionized water, rinse it thoroughly, and dry it.

[0021] Step 2, preparation of tin-antimony coating: Preparation of electroplating solution: Weigh 10 g / L of stannous chloride and 5 g / L of antimony trichloride, dissolve them in an aqueous solution containing 15% hydrochloric acid by volume, add 0.5 g / L of sodium saccharin and 1 g / L of polyethylene glycol as additives, and stir evenly.

[0022] Electroplating process: Pretreated titanium felt is used as the cathode and the graphite plate is used as the anode in the electroplating solution. The current density is controlled at 1A / dm², the temperature is 25°C, and the electroplating time is 20 minutes. A magnetic stirrer is used at a stirring speed of 100 rpm.

[0023] Post-plating treatment: The titanium felt coated with the tin-antimony coating was taken out, rinsed with deionized water, and dried in an oven at 100°C for 1 hour.

[0024] Step 3, platinum coating electroplating: Preparation of electroplating solution: Prepare an electroplating solution containing 5 g / L chloroplatinic acid, dissolve it in an aqueous solution containing 5% by volume sulfuric acid, and add 0.5 g / L disodium ethylenediaminetetraacetic acid and 0.1 g / L butynediol as additives.

[0025] Electroplating process: A titanium felt coated with tin-antimony as the cathode and a pure platinum sheet as the anode were placed in the electroplating solution. The current density was controlled at 0.5A / dm², the temperature was 40°C, the electroplating time was 30 minutes, and the stirring speed was 80 rpm.

[0026] Post-plating treatment: After electroplating, rinse clean, dry in an oven at 80°C for 0.5 hours, then soak in a passivation solution containing 2% nitric acid by volume for 3 minutes, take out, rinse and dry.

[0027] Step 4, coating inspection: Appearance inspection shows that the coating is uniform, smooth and free of defects; XRF inspection shows that the thickness of the platinum coating is 2μm and the thickness of the tin-antimony coating is 5μm; the scratch test shows that the adhesion reaches level 1; the electrochemical catalytic performance test shows good catalytic activity and stability.

[0028] Example 2

[0029] This embodiment discloses a process for electroplating a platinum coating on a titanium felt substrate, which specifically includes the following steps: Step 1: Pretreatment of titanium felt: Rinse the titanium felt with deionized water, soak it in an 8% sodium hydroxide solution, ultrasonically clean it at 55°C for 12 minutes, and then rinse it with deionized water until it is neutral. Next, soak it in a 12% hydrochloric acid solution at room temperature for 7 minutes, then ultrasonically clean it with deionized water for 20 minutes. Finally, rinse it with deionized water and dry it.

[0030] Step 2, preparation of tin-antimony coating: Preparation of electroplating solution: Weigh 15 g / L of stannous chloride and 7 g / L of antimony trichloride, dissolve them in an aqueous solution containing 20% hydrochloric acid by volume, add 0.8 g / L of sodium saccharin and 1.5 g / L of polyethylene glycol as additives, and stir evenly.

[0031] Electroplating process: Pretreated titanium felt is used as the cathode and the graphite plate is used as the anode in the electroplating solution. The current density is controlled at 2A / dm², the temperature is 30°C, and the electroplating time is 25 minutes. A magnetic stirrer is used at a stirring speed of 120 rpm.

[0032] Post-plating treatment: The titanium felt coated with tin-antimony coating was taken out, rinsed with deionized water, and dried in an oven at 110°C for 1.5 hours.

[0033] Step 3, platinum coating electroplating: Preparation of electroplating solution: Prepare an electroplating solution containing 7 g / L chloroplatinic acid, dissolve it in an aqueous solution containing 8% by volume sulfuric acid, and add 0.8 g / L disodium ethylenediaminetetraacetic acid and 0.2 g / L butynediol as additives.

[0034] Electroplating process: A titanium felt coated with tin-antimony as the cathode and a pure platinum sheet as the anode were placed in the electroplating solution. The current density was controlled at 1A / dm², the temperature was 45°C, the electroplating time was 35 minutes, and the stirring speed was 100 rpm.

[0035] Post-plating treatment: After electroplating is completed, rinse clean, dry in a 90°C oven for 0.8 hours, then soak in a passivation solution containing 3% nitric acid by volume for 4 minutes, take out, rinse and dry.

[0036] Step 4, coating inspection: Appearance inspection shows that the coating is uniform and has no obvious defects; XRF inspection shows that the thickness of the platinum coating is 3μm and the thickness of the tin-antimony coating is 7μm; the scratch method inspection shows that the adhesion reaches level 1; the corrosion resistance test shows that it performs well in a simulated corrosion environment.

[0037] Comparative Example 1 Platinum coating was directly electroplated on the surface of titanium felt without tin-antimony coating, with other conditions being the same as in Example 1. The results showed that the platinum coating had poor adhesion to the titanium felt substrate, with only a grade 3 adhesion test using the scratch test. The coating was prone to detachment during use, and the coating uniformity was not as good as in Example 1. Performance test results were also significantly lower than those of the sample prepared in Example 1.

[0038] Comparative Example 2 Tin-antimony and platinum coatings were prepared using conventional electroplating process parameters, with all other conditions being the same as in Example 2. The resulting coatings exhibited poor uniformity. The platinum coating exhibited uneven thickness, exceeding 6 μm in some areas and less than 2 μm in others. The tin-antimony coating also exhibited uneven thickness, and its adhesion tested only at level 2, resulting in overall performance inferior to that of the sample prepared in Example 2.

[0039] By comparing the examples and the comparative examples, it can be clearly seen that the process of electroplating a platinum coating on a titanium felt substrate of the present invention has significant advantages in improving coating adhesion, ensuring coating uniformity and enhancing comprehensive performance through reasonable pretreatment, intermediate layer priming and precise control of electroplating process parameters.

[0040] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A process for electroplating a platinum coating on a titanium felt substrate, characterized in that: The following steps are involved: Step 1, titanium felt pretreatment; Step 2, preparation of tin-antimony coating; Step 3, platinum coating electroplating; The step 1 is: Rinse the titanium felt with deionized water to remove dust and loose impurities on the surface; soak the titanium felt in a 5-10% sodium hydroxide solution by mass and ultrasonically clean it at 50-60°C for 10-15 minutes to remove oil stains and part of the oxide film on the surface; rinse the titanium felt repeatedly with deionized water until the rinse water is neutral; Place the cleaned titanium felt in a 10-15% hydrochloric acid solution and soak it at room temperature for 5-10 minutes to further remove the residual oxide film and impurities on the surface. Rinse it again with deionized water and ultrasonically clean it for 10-15 minutes, rinse it clean and dry it. The step 2 is: Preparation of electroplating solution: Weigh stannous chloride and antimony trichloride, with the concentration of stannous chloride controlled at 10-20 g / L and the concentration of antimony trichloride controlled at 5-10 g / L, dissolve them in an aqueous solution containing 15%-25% hydrochloric acid by volume, stir evenly, and prepare an electroplating solution; Electroplating: Use pretreated titanium felt as the cathode and graphite plate as the anode, and place them in the electroplating solution. During electroplating, control the current density to 1-3A / dm², maintain the temperature at 25-35°C, and electroplating for 20-30 minutes. During the electroplating process, use a magnetic stirrer to stir the electroplating solution at a stirring speed of 100-150 rpm. Post-plating treatment: After the electroplating is completed, the titanium felt coated with tin-antimony coating is removed from the electroplating solution, rinsed with deionized water, and then dried in an oven at 100-120°C for 1-2 hours to remove residual moisture on the surface and further solidify the tin-antimony coating; The step 3 is: Preparation of electroplating solution: Use chloroplatinic acid as the main salt, the concentration is controlled at 5-10g / L, and dissolve it in an aqueous solution containing 5-10% sulfuric acid by volume; Electroplating: Place a titanium felt coated with tin-antimony as the cathode and a pure platinum sheet as the anode in a prepared platinum electroplating solution. During electroplating, control the current density to 0.5-1.5A / dm², maintain the temperature at 40-50°C, and electroplating for 30-45 minutes. During the electroplating process, use a magnetic stirrer to stir the electroplating solution at a speed of 80-120 rpm. Post-plating treatment: After the electroplating is completed, the titanium felt with platinum coating is removed from the electroplating solution, rinsed with deionized water, and then dried in an oven at 80-100°C for 0.5-1 hour to remove residual moisture on the surface; the platinum coating is passivated by immersing it in a passivation solution containing 2-5% nitric acid by volume for 3-5 minutes at room temperature, then removed, rinsed with deionized water and dried to improve the corrosion resistance of the platinum coating.

2. The process for electroplating a platinum coating on a titanium felt substrate according to claim 1, characterized in that: During the preparation of the electroplating solution, additives including brightener and leveler are added to improve the quality of the tin-antimony coating.

3. The process for electroplating a platinum coating on a titanium felt substrate according to claim 2, wherein: The brightener is saccharin sodium with a concentration of 0.5-1 g / L; the leveling agent is polyethylene glycol with a concentration of 1-2 g / L.

4. The process for electroplating a platinum coating on a titanium felt substrate according to claim 1, wherein: During the preparation of the electroplating solution, additives including stabilizers and accelerators are added to improve the stability of platinum electroplating and the quality of the plating layer.

5. The process for electroplating a platinum coating on a titanium felt substrate according to claim 1, wherein: The stabilizer is disodium ethylenediaminetetraacetate with a concentration of 0.5-1 g / L; the accelerator is butynediol with a concentration of 0.1-0.3 g / L.

6. The process for electroplating a platinum coating on a titanium felt substrate according to claim 1, wherein: It also includes step 4 coating inspection, including appearance inspection, thickness inspection, adhesion inspection and product application performance inspection.