Method for electrodeposition of platinum layer on niobium or titanium material substrate surface in room temperature ionic liquid

Abstract

The application relates to a method for preparing a platinum layer on the surface of a niobium or titanium material matrix by electrodeposition in room-temperature ionic liquid, and belongs to the technical field of surface treatment. The method solves the technical problem of insufficient performance of the platinum layer prepared on the surface of the niobium or titanium material matrix by electrodeposition, and comprises the following steps: S1, preparing room-temperature ionic liquid; S2, pretreating the matrix; S3, acid washing and activating; S4, cleaning and soaking; S5, electrodeposition; and S6, post-treatment. The steps S3-S6 are all carried out in a protective atmosphere. The electrodeposition process temperature is at or near room temperature; the electrochemical window is wide; through optimization of the combination of the anion and cation ionic liquid, the ionic solution has adjustable physicochemical properties, thereby the oxidation-reduction potential and deposition morphology of platinum are regulated. The ionic liquid electrodeposition keeps the activated surface layer of the matrix clean, eliminates the hydrogen evolution reaction, realizes electrodeposition to obtain a platinum layer under room-temperature conditions, and the platinum layer has good interface bonding force, no porosity and dense crystallization.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology, specifically relating to a method for preparing a platinum layer by electrodeposition on a niobium or titanium substrate in a room-temperature ionic liquid. Background Technology

[0002] Niobium-based platinum materials and titanium-based platinum materials combine the high strength and corrosion resistance of niobium (Nb) and titanium (Ti) and their alloys with the excellent electrical conductivity and chemical stability of the platinum layer, demonstrating their significant application value in multiple high-tech fields. With their composite advantage of a "high-strength matrix + functional surface layer," they are irreplaceable in scenarios involving high temperature, high corrosion, and high-precision signal transmission. With the rapid development of intelligent sensing and control, hydrogen energy, energy storage, and medical technologies, their application prospects will further expand, especially in reducing platinum usage and improving adaptability to extreme environments.

[0003] Niobium-based platinum materials and titanium-based platinum materials can be used as electrodes in extreme environments. When titanium or niobium and their alloys are used alone, titanium itself is lightweight but has poor electrical conductivity, while niobium has good electrical conductivity, but it is prone to surface passivation in environments such as strong acids and high-temperature molten salts, resulting in a decrease in conductivity. Therefore, combining titanium and niobium with a platinum (Pt) layer electrodeposited on the surface can significantly improve the corrosion resistance and electrochemical activity of titanium and niobium.

[0004] After years of development, significant progress has been made in the electrodeposition of platinum using water as a solvent in aqueous solutions. This includes acidic platinum, basic platinum, and neutral platinum, all of which are used in production. However, overall, there are still some drawbacks: 1. Hydrogen evolution side reaction occurs during the electrodeposition of platinum layers in aqueous solution. Hydrogen atoms penetrate into the metal. Hydrogen exists in the interstitial space of the crystal lattice and can also focus at defects such as dislocations, grain boundaries, and pores, forming local high-concentration enrichment areas. This causes hydrogen embrittlement in the metal material, resulting in brittleness of the metal substrate and metal layer, causing the parts to break, the deposited metal layer to fall off, and shortening the service life.

[0005] 2. Platinum layers electrodeposited in aqueous solutions have high porosity, insufficient interfacial bonding, and a narrow electrochemical window in aqueous solutions. The current distribution in complex workpieces is uneven, which leads to insufficient uniform electrodeposition capability and limits its application in precision scenarios.

[0006] After years of development, the electrodeposition of platinum using organic solution systems with liquid organic matter as solvents has emerged. However, its poor conductivity, flammability, volatility, and relatively narrow operating temperature range have limited its development and application.

[0007] In addition, the high-temperature molten salt system for platinum electrodeposition using high-temperature molten salt as a solvent has a wide electrochemical window, but the operation process is complicated, the process control is difficult, and the energy consumption is high. The process temperature is >300℃, or even >500℃, the substrate is prone to thermal deformation, and the internal stress of the platinum layer is high. Summary of the Invention

[0008] To address the technical problem of insufficient performance of platinum layers prepared by electrodeposition on niobium or titanium substrates using existing technologies, this invention provides a method for preparing platinum layers by electrodeposition on niobium or titanium substrates in a room-temperature ionic liquid. The method employs a room-temperature ionic liquid system and, with the assistance of an inert gas atmosphere, utilizes a dual-pulse power supply and composite additives to synergistically deposit a platinum layer on the niobium or titanium substrate. The prepared platinum layer exhibits fine crystal structure, zero porosity, strong adhesion to the substrate, and a long service life.

[0009] This invention is achieved through the following technical solution: a method for preparing a platinum layer by electrodeposition on a niobium or titanium substrate in a room-temperature ionic liquid, comprising the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of the base solvent: Mix hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of (5~9):(5~1) at room temperature to prepare the base solvent; select imidazole-based and quaternary ammonium salt ionic liquids for compounding, wherein the cation is preferably a structure with a shorter carbon chain, and among various anions (such as halide ions, hexafluorophosphate, tetrafluoroborate, etc.), hexafluorophosphate (BMIM)PF6 is preferred; to reduce viscosity, improve the conductivity and cyclic stability of the ionic liquid, tetramethyl tetrafluoroborate (N 1111 BF4; S1-2, Dissolve a platinum salt with a concentration of 0.05 mol / L to 0.20 mol / L in the basic solvent prepared in step S1-1 to prepare a platinum-based room temperature ionic basic solution; S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are as follows: thiourea (CH4N2S): 0.005g / L-0.01g / L; citric acid (H3C6H5O7): 0.03g / L-0.1g / L; potassium citrate (K3C6H5O7): 0.03g / L-0.1g / L; dipotassium hydrogen phosphate (K2HPO4): 0.01g / L-0.05g / L; ascorbic acid (C6H8O6): 1g / L-3g / L; 1,2-propanediol (C3H8O2): 0.005g / L-0.01g / L; S2. Pretreatment of the substrate: The substrate is made of niobium or titanium. The substrate is immersed in a phosphorus-free environmentally friendly chemical degreasing agent and ultrasonically treated. The ultrasonic frequency is 28KHz~40KHz, the degreasing temperature is 50℃-80℃, and the degreasing time is 1-5 minutes. Steps S3 to S6 are all carried out in a protective atmosphere, with a flow rate of 0.5 L / min to 1 L / min. The protective gas covers the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid is maintained at ≤0.1 ppm. S3. Pickling and Activation: After the substrate pretreated in step S2 is washed with hot water, it is immersed in a pickling and activating agent. The pickling and activation temperature is 10℃-60℃, and the pickling and activation time is 0.5min-5min. The composition and ratio of the pickling and activating agent are as follows: hydrofluoric acid (HF): 30g / L-100g / L; nitric acid (HNO3): 0-300g / L; sulfuric acid (H2SO4): 150g / L-300g / L; aminosulfonic acid (H2NSO3H): 0-10g / L, and the remainder is water. S4. Cleaning and Immersion: Immerse the substrate activated by acid washing in step S3 in the immersion solution for 10-30 seconds. The composition and volume ratio of the immersion solution are as follows: ethanol (C2H5OH): 10%-90%; n-butanol (C4H9OH): 10%-90%, and the sum of the proportions of each component is 100%. Dry the substrate after immersion with protective gas and place it in an ultrasonic electrodeposition tank. S5. Electrodeposition: The room-temperature ionic liquid prepared in steps S1-3 is added to the ultrasonic electrodeposition tank and the substrate is immersed. The substrate is used as the cathode electrode. The anode electrode is made of pure platinum, niobium-based platinum or titanium-based platinum. The anode electrode is plate-shaped or mesh-shaped. The effective deposition area ratio of the cathode electrode to the anode electrode is 1:(1-2). The dual-pulse power supply is activated at a frequency of 40Hz-120Hz. Forward pulses have a current density of 0.5-30A / dm², a pulse width of 5-20ms, and a duty cycle of 10%-50%. Reverse pulses have a current density of 0.25-30A / dm², a pulse width of 5-20ms, and a duty cycle of 5%-20%. The ultrasonic frequency of the ultrasonic electrodeposition tank is set to 28kHz-40kHz, and the electrodeposition temperature is set to 10℃-80℃. A platinum layer is electrodeposited on the substrate surface. The thickness of the electrodeposited platinum layer is controlled by adjusting the forward and reverse pulse current densities, pulse widths, and duty cycles of the pulse power supply, as well as parameters such as temperature, solution concentration, and electrodeposition time. S6. Post-processing: Take out the substrate with the electrodeposited platinum layer from step S5 and immerse it in the immersion solution. The composition and volume ratio of the immersion solution are: ethanol (C2H5OH): 10%-90%; n-butanol (C4H9OH): 10%-90%, and the sum of the ratios of the components is 100%. The immersion time is 10s-30s. After immersion, it is dried with a protective gas and finally placed in an oven at 80℃ for 1-2 hours to obtain niobium or titanium material with a surface electrodeposited platinum layer.

[0010] Further, in steps S1-2, the platinum salt is platinum tetrachloride (PtCl4), chloroplatinic acid (H2PtCl4), dinitrodiammineplatinum (Pt(NH3)2(NO3)2) or potassium tetranitroplatinate (K2Pt(NO2)4).

[0011] Further, in step S2, the composition and proportion of the phosphorus-free environmentally friendly chemical degreasing agent are as follows: sodium hydroxide (NaOH): 10wt%-15wt%; sodium carbonate (Na2CO3): 15wt%-20wt%; sodium silicate (Na2SiO3): 10wt%-15wt%; sodium EDTA-2 (C 10 H 14 N2Na2O8·2H2O): 1wt%-3wt%; JFC penetrant: 1wt%-5wt%; betaine: 0.2wt%-1.0wt%, the remainder being water.

[0012] Furthermore, the protective atmosphere is at least one of carbon dioxide, nitrogen, or argon.

[0013] The beneficial effects of this invention are as follows: the electrodeposition process temperature is at or near room temperature; the electrochemical window is wide; and through the optimized combination of anion and cation liquids, the ionic solution possesses adjustable physicochemical properties, thereby controlling the redox potential and deposition morphology of platinum. This ionic liquid electrodeposition process for platinum layers combines the advantages of aqueous solutions, high-temperature molten salts, and organic solvents. Ionic liquid electrodeposition keeps the activated surface of the substrate clean, eliminates the hydrogen evolution reaction, and achieves platinum layer deposition at room temperature. Simultaneously, it achieves platinum layers with good adhesion, no porosity, and dense crystallinity, which were previously only obtainable with high-temperature molten salts. Attached Figure Description

[0014] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 An optical microscope image (magnification 200x) of the niobium-based material with a surface electrodeposited platinum layer prepared in Example 1. Figure 3 SEM image of the niobium-based material with a surface electrodeposited platinum layer prepared in Example 1; Figure 4EDS curve of the niobium-based material with a surface electrodeposited platinum layer prepared in Example 1; Figure 5 An optical microscope image (magnification 200x) of the titanium-based material with a surface electrodeposited platinum layer prepared in Example 2. Figure 6 SEM image of the titanium-based material with a surface electrodeposited platinum layer prepared in Example 2; Figure 7 EDS curve of titanium-based material with surface electrodeposited platinum layer prepared in Example 2. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Example 1

[0016] like Figure 1 As shown, Example 1 provides a method for electrodepositing a platinum layer on a niobium substrate in a room-temperature ionic liquid. The niobium substrate is a niobium plate with a purity of 99.5% and dimensions of 100 mm in length, 50 mm in width, and 1.5 mm in thickness. The preparation method includes the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of basic solvent: Mix 1-methyl-3-butylimidazolium hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of 8:2 at room temperature to prepare the basic solvent. S1-2. Dissolve 0.05 mol / L H2PtCl4 in the basic solvent prepared in step S1-1 to prepare a platinum-based room temperature ion basic solution. S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are as follows: K2HPO4: 0.02 g / L; C6H8O6: 2 g / L; CH4N2S: 0.005 g / L; C3H8O2: 0.005 g / L; S2. Matrix Pretreatment: The matrix is ​​immersed in a phosphorus-free environmentally friendly chemical degreasing agent and ultrasonically treated at a frequency of 28 kHz, a degreasing temperature of 50℃-80℃, and a degreasing time of 3 minutes. The composition and ratio of the phosphorus-free environmentally friendly chemical degreasing agent are as follows: NaOH: 11 wt%; Na2CO3: 15 wt%; Na2SiO3: 12 wt%; C 10 H 14 N2Na2O8·2H2O: 2wt%; JFC penetrant: 3wt%; betaine: 0.5wt%, the remainder being water; The following steps S3 to S6 are all carried out in a nitrogen protective atmosphere, with a flow rate of 0.5 L / min, the protective gas covering the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid maintained at ≤0.1 ppm; S3. Pickling and Activation: After the substrate pretreated in step S2 is washed with hot water, it is immersed in a pickling and activating agent. The pickling and activating temperature is 15±2℃ and the pickling and activating time is 3min. The composition and ratio of the pickling and activating agent are as follows: HF: 40g / L; HNO3: 150g / L; H2SO4: 300g / L; H2NSO3H: 5g / L, with the remainder being water. S4. Cleaning and soaking: Immerse the substrate after acid washing and activation in step S3 in the soaking solution for 10 seconds; the composition and volume ratio of the soaking solution are: C2H5OH: 20%; C4H9OH: 80%; use protective gas to dry the soaked substrate and place it in an ultrasonic electrodeposition tank. S5. Electrodeposition: Add the room temperature ionic liquid prepared in steps S1-3 into the ultrasonic electrodeposition tank and immerse the substrate, using the substrate as the cathode electrode; the anode is a titanium-platinum mesh with dimensions of 110 mm in length × 60 mm in width × 2 mm in thickness. Start the dual-pulse power supply. The frequency of the dual-pulse power supply is 50Hz, where the positive pulse current density is 10A / dm². 2 The pulse width is 20ms and the duty cycle is 20%; the reverse pulse has a current density of 5A / dm³. 2 The pulse width was 5ms and the duty cycle was 10%. The ultrasonic frequency of the ultrasonic electrodeposition tank was set to 40KHz, the electrodeposition temperature was 25℃, and the electrodeposition time was 10min. A platinum layer was electrodeposited on the surface of the niobium substrate. S6. Post-processing: Remove the substrate with the electrodeposited platinum layer from step S5 and immerse it in an immersion solution. The composition and volume ratio of the immersion solution are: C2H5OH: 90%; C4H9OH: 10%; the immersion time is 10s-30s. After immersion, dry it with a protective gas and finally dry it at 80℃ for 1 hour to obtain the niobium material with the surface electrodeposited platinum layer. The microstructure morphology of the niobium material with the surface electrodeposited platinum layer prepared in Example 1 is as follows: Figure 2 As shown.

[0017] According to the thickness gauge specified in GB / T 16921-2005 "Metallic Coating Thickness Measurement by X-ray Spectroscopy", the platinum layer thickness is 3±0.2μm.

[0018] According to GB / T5270-2005 "Review of Test Methods for Adhesion Strength of Electrodeposited and Chemically Deposited Metallic Coatings on Metallic Substrates", a 30° sharp-edged hard steel scratching knife can scratch 1mm squares over 3cm. 2 Internal observations showed no platinum layer detachment.

[0019] According to GB / T19351-2003 Determination of porosity of coatings on metal substrates: Nitric acid vapor test, nitric acid 69±2%, temperature 23±3℃, humidity RH 40-55%, after 60 minutes, the sample was taken out and exposed. There were no bubbles on the surface of the platinum layer. The sample was then dried in an oven at 130℃ for 60 minutes. The surface was magnified 10 times. There were no corrosion products, and the sample was identified as having no porosity.

[0020] SEM image of the niobium material with a surface electrodeposited platinum layer prepared in Example 1 (as shown in Figure 1) Figure 2 The cross-section shown shows that the platinum layer is dense and non-porous; the EDS image of the niobium material with the surface electrodeposited platinum layer prepared in Example 1 (as shown) Figure 3 As shown in the figure, the platinum layer is extremely thin, so EDS contains some Nb matrix components in addition to Pt. Example 2

[0021] like Figure 1 As shown, this embodiment 2 provides a method for electrodepositing a platinum layer on the surface of a titanium substrate in a room-temperature ionic liquid. The titanium substrate is a titanium mesh with a purity of 99.5% and dimensions of 100 mm in length × 50 mm in width × 2 mm in thickness. The mesh size is 10 mm in length × 5 mm in width. The preparation method includes the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of basic solvent: Mix 1-methyl-3-butylimidazolium hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of 7:3 at room temperature to prepare the basic solvent. S1-2, Dissolve 0.08 mol / L PtCl4 in the base solvent prepared in step S1-1 to prepare a platinum-based room temperature ion base solution; S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are: K2HPO4: 0.05g / L; C6H8O6: 5g / L; C3H8O2: 0.001g / L; S2. Matrix Pretreatment: The matrix is ​​immersed in a phosphorus-free environmentally friendly chemical degreasing agent and ultrasonically treated at a frequency of 28 kHz, a degreasing temperature of 55°C, and a degreasing time of 5 minutes. The composition and ratio of the phosphorus-free environmentally friendly chemical degreasing agent are: NaOH: 15 wt%; Na2CO3: 12 wt%; Na2SiO3: 10 wt%; C 10 H 14 N2Na2O8·2H2O: 1wt%; JFC penetrant: 2wt%; betaine: 0.5wt%, the remainder being water; The following steps S3 to S6 are all carried out in a nitrogen protective atmosphere, with a flow rate of 0.5 L / min, the protective gas covering the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid maintained at ≤0.1 ppm; S3, Pickling and Activation: After the substrate pretreated in step S2 is washed with hot water, it is immersed in a pickling and activating agent. The pickling and activation temperature is 20-25℃, and the pickling and activation time is 5 minutes. The composition and ratio of the pickling and activating agent are: HF: 50g / L; H2SO4: 250g / L; the remainder is water. S4. Cleaning and soaking: Immerse the substrate after acid washing and activation in step S3 in the soaking solution for 20 seconds; the composition and volume ratio of the soaking solution are: C2H5OH: 90%; C4H9OH: 10%; use protective gas to dry the soaked substrate and place it in an ultrasonic electrodeposition tank. S5. Electrodeposition: The room-temperature ionic liquid prepared in steps S1-3 is added to the ultrasonic electrodeposition tank and the substrate is immersed. The substrate is used as the cathode electrode. The anode is a niobium-based platinum mesh with dimensions of 100 mm in length, 50 mm in width, and 1.5 mm in thickness. Start the dual-pulse power supply. The frequency of the dual-pulse power supply is 40Hz, and the positive pulse current density is 30A / dm². 2 The pulse width is 5ms and the duty cycle is 15%; the reverse pulse has a current density of 15A / dm³. 2 The pulse width was 5ms and the duty cycle was 30%. The ultrasonic frequency of the ultrasonic electrodeposition tank was set to 40KHz, the electrodeposition temperature was 20℃, and the electrodeposition time was 5min. A platinum layer was electrodeposited on the substrate surface. S6. Post-processing: This step is the same as step S6 in Example 1, and will not be repeated here. A titanium material with a surface electrodeposited platinum layer is obtained. The microstructure morphology of the titanium material with a surface electrodeposited platinum layer prepared in Example 2 is as follows: Figure 5 As shown.

[0022] According to the thickness gauge specified in GB / T 16921-2005 "Metallic Coating Thickness Measurement by X-ray Spectroscopy", the platinum layer thickness was 5 ± 0.2 μm.

[0023] According to GB / T5270-2005 "Review of Test Methods for Adhesion Strength of Electrodeposited and Chemically Deposited Metallic Coatings on Metallic Substrates", a 30° sharp-edged hard steel scratching knife can scratch 1mm squares over 3cm. 2 Internal observations showed no platinum layer detachment.

[0024] According to GB / T19351-2003 Determination of porosity of coatings on metal substrates: Nitric acid vapor test, nitric acid 69±2%, temperature 23±3℃, humidity RH 40-55%, after 75 minutes the sample was taken out and exposed. There were no bubbles on the surface of the platinum layer. The sample was then dried in an oven at 130℃ for 60 minutes. The surface was magnified 10 times and no corrosion products were found. The sample was identified as having no porosity.

[0025] SEM image of the titanium material with a surface electrodeposited platinum layer prepared in Example 2 (as shown in Figure 2) Figure 6 The cross-section shown shows that the platinum layer is dense and without pores; the EDS image of the titanium material with the surface electrodeposited platinum layer prepared in Example 2 (as shown) Figure 7 As shown in the figure, due to the extremely thin platinum layer, EDS contains some Ti matrix components in addition to Pt. Example 3

[0026] like Figure 1 As shown in Example 3, this embodiment provides a method for electrodepositing a platinum layer on a niobium substrate surface in a room-temperature ionic liquid. The niobium substrate is a niobium mesh with a purity of 99.5%, dimensions of 150 mm in length × 100 mm in width × 1.5 mm in thickness, and the mesh size is 12 mm in length × 6 mm in width. The preparation method includes the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of basic solvent: Mix 1-methyl-3-butylimidazolium hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of 9:1 at room temperature to prepare the basic solvent. S1-2, Dissolve 0.2 mol / L K2Pt(NO2)4 in the base solvent prepared in step S1-1 to prepare a platinum-based room temperature ionic base solution; S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are: C6H8O6: 2.5g / L; H3C6H5O7: 0.05g / L; S2. Matrix Pretreatment: The matrix is ​​immersed in a phosphorus-free environmentally friendly chemical degreasing agent and ultrasonically treated at a frequency of 40 kHz, a degreasing temperature of 50℃-80℃, and a degreasing time of 3 minutes. The composition and ratio of the phosphorus-free environmentally friendly chemical degreasing agent are as follows: NaOH: 11 wt%; Na2CO3: 15 wt%; Na2SiO3: 12 wt%; C 10 H 14 N2Na2O8·2H2O: 2wt%; JFC penetrant: 3wt%; betaine: 0.5wt%, the remainder being water; The following steps S3 to S6 are all carried out in a nitrogen protective atmosphere, with a flow rate of 0.5 L / min, the protective gas covering the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid maintained at ≤0.1 ppm; S3, Pickling and Activation: After the substrate pretreated in step S2 is washed with hot water, it is immersed in a pickling and activating agent. The pickling and activation temperature is room temperature, and the pickling and activation time is 10 min. The composition and ratio of the pickling and activating agent are: HF: 40 g / L; HNO3: 150 g / L; H2SO4: 200 g / L, and the remainder is water. S4. Cleaning and soaking: Immerse the substrate after acid washing and activation in step S3 in the soaking solution for 10 seconds; the composition and volume ratio of the soaking solution are: C2H5OH: 20%; C4H9OH: 80%; use protective gas to dry the soaked substrate and place it in an ultrasonic electrodeposition tank. S5. Electrodeposition: Add the room temperature ionic liquid prepared in steps S1-3 into the ultrasonic electrodeposition tank and immerse the substrate, using the substrate as the cathode electrode; the anode is a titanium-platinum mesh with dimensions of 200mm in length × 150mm in width × 1mm in thickness. Start the dual-pulse power supply. The frequency of the dual-pulse power supply is 50Hz, and the positive pulse current density is 20A / dm². 2 The pulse width is 20ms and the duty cycle is 30%; the reverse pulse has a current density of 10A / dm³. 2 The pulse width was 5ms and the duty cycle was 15%. The ultrasonic frequency of the ultrasonic electrodeposition tank was set to 40KHz, the electrodeposition temperature to 40℃, and the electrodeposition time to 10min, so as to electrodeposit a platinum layer on the substrate surface. S6. Post-processing: Take out the substrate of the electrodeposited platinum layer in step S5 and immerse it in the immersion solution. The composition and volume ratio of the immersion solution are: C2H5OH: 80%; C4H9OH: 20%; the immersion time is 20s. After immersion, it is dried with protective gas and finally dried in an environment at 60℃ for 2 hours to obtain the niobium material with the electrodeposited platinum layer on the surface.

[0027] According to the thickness gauge specified in GB / T 16921-2005 "Metallic Coating Thickness Measurement by X-ray Spectroscopy", the platinum layer thickness was 8±0.5μm.

[0028] According to GB / T5270-2005 "Review of Test Methods for Adhesion Strength of Electrodeposited and Chemically Deposited Metallic Coatings on Metallic Substrates", a 30° sharp-edged hard steel scratching knife can scratch 1mm squares over 3cm. 2 Internal observations showed no platinum layer detachment.

[0029] According to GB / T19351-2003 Determination of porosity of coatings on metal substrates: Nitric acid vapor test, nitric acid 69±2%, temperature 23±3℃, humidity RH 40-55%, after 75 minutes the sample was taken out and exposed. There were no bubbles on the surface of the platinum layer. The sample was then dried in an oven at 130℃ for 60 minutes. The surface was magnified 10 times and no corrosion products were found. The sample was identified as having no porosity. Example 4

[0030] like Figure 1 As shown, Example 4 provides a method for electrodepositing a platinum layer on a titanium substrate in a room-temperature ionic liquid. The titanium substrate is a titanium mesh with a purity of 99.5% and dimensions of 150 mm in length × 150 mm in width × 1 mm in thickness. The preparation method includes the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of basic solvent: Mix 1-methyl-3-butylimidazolium hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of 6:4 at room temperature to prepare the basic solvent. S1-2, Dissolve Pt(NH3)2(NO3)2 with a concentration of 0.015 mol / L in the basic solvent prepared in step S1-1 to prepare a platinum-based room temperature ionic basic solution; S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are as follows: H3C6H5O7: 0.1g / L; K2HPO4: 0.02g / L; ascorbic acid: 1.5g / L; C6H8O6: 0.01g / L; C3H8O2: 0.01g / L; S2. Matrix pretreatment: This step is the same as step S2 of Example 2, which is matrix pretreatment and will not be described in detail here. The following steps S3 to S6 are all carried out in an argon protective atmosphere, with a flow rate of 0.5 L / min, the protective gas covering the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid maintained at ≤0.1 ppm; In this embodiment 4, steps S3 acid washing and activation and S4 cleaning and soaking are the same as in embodiment 2, and will not be described in detail here. S5. Electrodeposition: The room-temperature ionic liquid prepared in steps S1-3 is added to the ultrasonic electrodeposition tank and the substrate is immersed. The substrate is used as the cathode electrode. The anode is a niobium-based platinum mesh with dimensions of 200 mm in length, 200 mm in width, and 1.5 mm in thickness. Start the dual-pulse power supply. The frequency of the dual-pulse power supply is 100Hz, where the positive pulse current density is 0.5A / dm. 2 The pulse width is 5ms and the duty cycle is 25%; the reverse pulse has a current density of 5A / dm³. 2The pulse width was 3ms and the duty cycle was 5%. The ultrasonic frequency of the ultrasonic electrodeposition tank was set to 40KHz, the electrodeposition temperature to 50℃, and the electrodeposition time to 2h, so as to electrodeposit a platinum layer on the substrate surface. S6. Post-processing: This step is the same as step S6 in Example 3, and will not be described in detail here. A titanium material with a platinum electrodeposited on the surface is obtained.

[0031] According to the thickness gauge specified in GB / T 16921-2005 "Metallic Coating Thickness Measurement by X-ray Spectroscopy", the platinum layer thickness is 1.5 ± 0.5 μm.

[0032] According to GB / T19351-2003 Determination of porosity of coatings on metal substrates: Nitric acid vapor test, nitric acid 69±2%, temperature 23±3℃, humidity RH 40-55%, after 75 minutes the sample was taken out and exposed. There were no bubbles on the surface of the platinum layer. The sample was then dried in an oven at 130℃ for 60 minutes. The surface was magnified 10 times and no corrosion products were found. The sample was identified as having no porosity.

[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a platinum layer by electrodeposition on a niobium or titanium substrate in an ionic liquid, characterized in that, Includes the following steps: S1. Preparation of room temperature ionic solution: S1-1. Preparation of basic solvent: Mix 1-methyl-3-butylimidazolium hexafluorophosphate solution and tetramethyl tetrafluoroborate quaternary ammonium salt solution at a molar ratio of 8:2 at room temperature to prepare the basic solvent. S1-2. Dissolve 0.05 mol / L H2PtCl4 in the basic solvent prepared in step S1-1 to prepare a platinum-based room temperature ion basic solution. S1-3. Add additives to the platinum-based room-temperature ionic base solution prepared in step S1-2, and after complete dissolution, prepare a room-temperature ionic liquid for later use; the composition and ratio of the additives are as follows: dipotassium hydrogen phosphate: 0.02 g / L; ascorbic acid: 2 g / L; thiourea: 0.005 g / L; 1,2-propanediol: 0.005 g / L; S2. Pretreatment of the substrate: The substrate is made of niobium or titanium. The substrate is immersed in a phosphorus-free environmentally friendly chemical degreasing agent and ultrasonically treated. The ultrasonic frequency is 28KHz, the degreasing temperature is 50℃-80℃, and the degreasing time is 3 minutes. Steps S3 to S6 are all carried out in a protective atmosphere, with a flow rate of 0.5 L / min, the protective gas covering the surface of the ionic liquid, and the dissolved oxygen content of the ionic liquid maintained at ≤0.1 ppm; S3. Pickling and Activation: After the substrate pretreated in step S2 is washed with hot water, it is immersed in a pickling and activating agent. The pickling and activating temperature is 15±2℃, and the pickling and activating time is 3min. The composition and ratio of the pickling and activating agent are as follows: hydrofluoric acid: 40g / L; nitric acid: 150g / L; sulfuric acid: 300g / L; aminosulfonic acid: 5g / L, and the remainder is water. S4. Cleaning and soaking: Immerse the substrate after acid washing and activation in step S3 in the soaking solution for 10 seconds; the composition and volume ratio of the soaking solution are: ethanol: 20%; n-butanol: 80%; use protective gas to dry the soaked substrate and place it in an ultrasonic electrodeposition tank. S5. Electrodeposition: The room temperature ionic liquid prepared in step S1-3 is added to the ultrasonic electrodeposition tank and the substrate is immersed, and the substrate is used as the cathode electrode. The anode uses a titanium-platinum mesh; The dual-pulse power supply is started at a frequency of 50Hz. The forward pulse has a current density of 10A / dm², a pulse width of 20ms, and a duty cycle of 20%. The reverse pulse has a current density of 5A / dm², a pulse width of 5ms, and a duty cycle of 10%. The ultrasonic frequency of the ultrasonic electrodeposition tank is set to 40KHz, and the electrodeposition temperature is set to 25℃. A platinum layer is electrodeposited on the substrate surface. S6. Post-processing: Take out the substrate of the electrodeposited platinum layer in step S5 and immerse it in the immersion solution. The composition and volume ratio of the immersion solution are: ethanol: 90%; n-butanol: 10%; the immersion time is 10s-30s. After immersion, blow it dry with protective gas and finally dry it in an environment at 80℃ for 1 hour to obtain niobium or titanium material with electrodeposited platinum layer on the surface.

2. The method for preparing a platinum layer by electrodeposition on a niobium or titanium substrate in an ionic liquid according to claim 1, characterized in that, In step S2, the composition and proportion of the phosphorus-free environmentally friendly chemical degreasing agent are as follows: sodium hydroxide: 11wt%; sodium carbonate: 15wt%; sodium silicate: 12wt%; sodium EDTA-2: 2wt%; JFC penetrant: 3wt%; betaine: 0.5wt%; and the remainder is water.

3. The method for preparing a platinum layer by electrodeposition on a niobium or titanium substrate in an ionic liquid according to claim 1, characterized in that, The protective atmosphere is at least one of carbon dioxide, nitrogen, or argon.

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