Titanium-based-iridium tantalum oxidation coating anode and preparation method and application thereof

Abstract

The invention discloses a titanium-based-iridium tantalum oxidation coating anode and a preparation method and application thereof, and belongs to the technical field of anode preparation, and the preparation process of the titanium-based-iridium tantalum oxidation coating anode comprises the steps that a titanium substrate is brushed with a solution containing a tantalum source A, then sintering is conducted, brushing-sintering is repeated, and a tantalum-coated titanium substrate is obtained; the tantalum-coated titanium substrate is brushed with the iridium-tantalum oxidation coating liquid, then sintering is carried out, and brushing-sintering is repeated, so that the tantalum-coated titanium substrate is obtained; the iridium-tantalum oxidation coating liquid contains a tantalum source B, an iridium source and a zirconium source; in the iridium tantalum oxidation coating liquid, the mass ratio of tantalum to iridium is (6-7): (4-5), according to the preparation method provided by the invention, through two times of brushing, the tantalum content in the titanium-based-iridium tantalum oxidation coating anode is more than 5% greater than the iridium content, and when the titanium-based-iridium tantalum oxidation coating anode is used for an alkaline citric acid electroplating system, the decomposition of a complexing agent can be effectively inhibited, the components of the electroplating liquid are maintained to be stable, so that the quality of a plating layer is ensured, and the service life of the plating layer is prolonged. The maintenance cost of the plating solution is reduced and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anode preparation, and particularly relates to a titanium-based iridium-tantalum oxide coating anode and a preparation method and application thereof. BACKGROUND

[0002] The complexing agent in a citric acid electroplating system has the functions of controlling the concentration of metal ions, improving the dispersing ability and covering ability, etc. In an alkaline citric acid electroplating system, the insoluble anodes commonly used are stainless steel, platinum anode and titanium-based coating anode, etc. Although the stainless steel anode is low in price, it not only has a slight dissolution in the alkaline plating solution, but also has a situation of excessive accumulation of complexing agent with the aging of the plating solution. The excessive complexing agent will excessively complex with the metal ion of the main salt, which will reduce the free metal ion, seriously affect the deposition of the main salt in the plating solution, reduce the current efficiency and electroplating rate, and further affect the performance of the plating layer. The noble metal anode such as platinum anode is limited in wide use due to the high price, and therefore, the titanium-based coating anode is currently considered to be used, wherein the oxygen evolution type titanium-based iridium-tantalum oxide coating anode (Ti / IrO2+Ta2O5) is commonly used as the electroplating anode because it has no risk of dissolving and contaminating the plating solution compared with the stainless steel anode, and is relatively low in price compared with the noble metal anode.

[0003] The existing titanium-based iridium-tantalum oxide coating anode in the market is mainly suitable for use in an acid electroplating process, such as electroplating processes such as chromium plating and nickel plating. In the iridium-tantalum oxide coating, the molar ratio of iridium to tantalum is controlled at 6:4-7:3. If the content of tantalum is too high, a large number of cracks with large sizes will be formed in the coating. The oxygen electrolytically separated out is easy to diffuse to the titanium substrate through the cracks, so that the titanium substrate forms a non-conductive titanium oxide passivation film, which not only hinders the conduction of current, but also damages the adhesion between the coating and the substrate, and causes the peeling of the coating. The above-mentioned ratio can not only retain the function of the tantalum oxide in enhancing the stability of the coating, but also ensure that the iridium oxide provides sufficient active sites. However, the above-mentioned titanium-based iridium-tantalum oxide coating anode is not suitable for use in an alkaline electroplating process. In the alkaline electroplating process, the alkaline solution will accelerate the dissolution or structural damage of the iridium and tantalum oxides in the coating, which will greatly shorten the service life of the anode. In addition, due to the strong catalytic effect of the noble metal (Ir) in the anode, the complexing agent will be excessively decomposed, which will cause the imbalance of the components in the plating solution, reduce the current efficiency, and affect the quality of the plating layer and the service life of the plating solution. Moreover, the decomposition products generated by the excessive decomposition of the complexing agent will have adverse effects on the performance of the plating layer, and therefore, the plating solution needs to be regularly adsorbed and filtered, which will reduce the production efficiency. SUMMARY

[0004] In order to solve the above-mentioned problems, the first object of the present application is to provide a preparation method of a titanium-based iridium-tantalum oxide coating anode.

[0005] A second objective of this invention is to provide a titanium-based iridium-tantalum oxide-coated anode prepared by the above-described preparation method.

[0006] A third objective of this invention is to provide an application of a titanium-based iridium-tantalum oxide-coated anode prepared by the above-described preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The present invention discloses a method for preparing a titanium-based iridium-tantalum oxide coated anode, comprising the following steps:

[0009] Step 1

[0010] A solution containing tantalum source A is brushed onto a titanium substrate, and then sintered. This brushing-sintering process is repeated to obtain a tantalum-coated titanium substrate.

[0011] Step Two

[0012] The iridium-tantalum oxide coating solution is brushed onto the tantalum-titanium substrate and then sintered. The brushing-sintering process is repeated to obtain the final product.

[0013] The iridium-tantalum oxide coating solution contains tantalum source B, iridium source, and zirconium source;

[0014] In the iridium-tantalum oxide coating solution, the mass ratio of tantalum to iridium is 6~7:4~5.

[0015] The preparation method provided by this invention, through two coating processes, ensures that the tantalum content in the titanium-based iridium-tantalum oxide coating anode is greater than 5% of the iridium content. When used in an alkaline citric acid electroplating system, it effectively inhibits the decomposition of the complexing agent, maintains the stability of the plating solution composition, thereby guaranteeing coating quality, reducing plating solution maintenance costs, and extending service life. This is because Ta₂O₅ is an inert component with strong chemical stability. It not only stabilizes the contact area between IrO₂ and the titanium substrate but also effectively inhibits the sharp increase in electrode potential that occurs when oxygen evolution reaction takes place at the anode in an electrolyte containing organic matter, leading to the decomposition of the organic matter. To stabilize the plating solution composition, and to avoid the problem of excessive tantalum content causing numerous large cracks in the coating, this invention first uses a solution containing tantalum source A to brush onto a titanium substrate. Through sintering, a highly conductive tantalum β phase is obtained. Then, by adding a zirconium source to the iridium-tantalum oxide coating solution and sintering again, the zirconium effectively refines the coating grains, fills microcracks in the iridium-tantalum anode, and improves the coating density, avoiding excessive amounts that could cause the coating to crack or decrease in conductivity. Thus, under the preparation method of this invention, a dense titanium-based iridium-tantalum oxide coating anode that is stable in a neutral to slightly alkaline citric acid electroplating system is obtained.

[0016] Preferably, in step one, the titanium substrate is sequentially subjected to water washing, sandpaper polishing, sand blasting, oil removal, water washing, acid immersion, water washing and drying treatment. Through the above pretreatment process, the oxide film on the surface of the titanium alloy can be effectively removed, forming a more uniform and suitable roughness plating surface, greatly improving the bonding force between the titanium alloy workpiece and the plating layer. In actual operation, 800 mesh sandpaper is used for polishing.

[0017] Further preferably, the sand used for sand blasting is quartz sand with a sand particle size of 80-120 mesh, and the sand blasting pressure is 3-4 kg / cm 2 .

[0018] By controlling the sand blasting conditions within the above range, the most suitable roughness is obtained, and the final coating has the best bonding performance.

[0019] Further preferably, the oil removal process is to place the titanium substrate in an alkali solution to remove oil, and the oil removal temperature is controlled at 70-80°C. The alkali solution comprises the following components: NaOH 30-50 g / L, Na2CO3 30-50 g / L, Na2PO4 30-50 g / L.

[0020] Further preferably, the acid immersion process is to place the titanium substrate in an oxalic acid solution at 100-110°C for 1-2h or in a hydrochloric acid solution at room temperature for 2-3h. In the oxalic acid solution, the mass fraction of oxalic acid is 10-15%, and in the hydrochloric acid solution, the mass fraction of HCl is 30-38%.

[0021] Preferably, in step one, the solution containing tantalum source A is a tantalum pentachloride solution, and the mass fraction of tantalum pentachloride in the tantalum pentachloride solution is 10-15%. If the mass fraction of tantalum pentachloride in the solution containing tantalum source A is controlled within this range, the performance is optimal. If the mass fraction is too large, the coating after sintering is uneven, and if the mass fraction is too small, the coating is too thin, causing missed coating and affecting corrosion resistance.

[0022] Preferably, in step one, the solution containing tantalum source A is brushed on the titanium substrate, and then sintered, and the brushing-sintering process is repeated 2-5 times, preferably 4-5 times. The sintering temperature is 600-620°C, and the holding time for the last sintering is 1-2h, and the holding time for the other times is 20-30 min.

[0023] The solution containing the tantalum source A is brushed multiple times in the present application to ensure the thickness of the coating layer, guarantee the compactness of the coating layer, the intermediate holding time is controlled in 20-30 min, which plays a transitional role, converts the tantalum source into oxide, improves the growth efficiency, and the last time is holding at 600-620℃ for a long time to complete the conversion of the crystal form, therefore, the holding temperature needs to be effectively controlled, if the temperature is too low, the alpha phase will be formed, which reduces the conductivity, and if the temperature is too high, the density will be reduced.

[0024] In the preferred scheme, in step two, the tantalum source B in the iridium-tantalum oxide coating solution is tantalum pentachloride, the iridium source is chloro iridic acid hexahydrate, and the zirconium source is zirconium chloride.

[0025] Further preferably, in the iridium-tantalum oxide coating solution, the amount of zirconium chloride added is 2%-5% of the total moles of tantalum pentachloride and chloro iridic acid hexahydrate. Controlling the amount of zirconium source added in this range can effectively refine the coating grain, fill the micro-cracks in the iridium-tantalum anode, improve the compactness of the coating layer, and avoid excessive coating cracking or conductivity reduction.

[0026] In the preferred scheme, in step two, the iridium-tantalum oxide coating solution is obtained by adding tantalum pentachloride, chloro iridic acid hexahydrate and zirconium chloride into a mixed solvent composed of hydrochloric acid and n-butanol, and ultrasonic treatment for 30-60 min.

[0027] Further preferably, in the iridium-tantalum oxide coating solution, the mass fraction of n-butanol is 60%-75%, and the mass fraction of HCl is 5%-15%.

[0028] In the preferred scheme, in step two, the iridium-tantalum oxide coating solution is brushed on the tantalum-coated titanium substrate, and then sintered, and the brushing-sintering process is repeated for 10-15 times, the temperature of the last sintering is 450-520℃, the holding time of the last sintering is 1-2 h, the temperature of the remaining sintering is 450-530℃, and the holding time of the remaining sintering is 10-30 min. The above coating-sintering process is adopted, and the performance of the finally obtained coating layer is optimal.

[0029] The present application also provides a titanium-based iridium-tantalum oxide coating anode prepared by the above preparation method, wherein the mass fraction of tantalum is 13%-56%, the mass fraction of iridium is 7%-20%, and the mass fraction of tantalum is more than 5% higher than the mass fraction of iridium.

[0030] The present application also provides the application of the titanium-based iridium-tantalum oxide coating anode prepared by the above preparation method, which is applied to a citric acid electroplating system, and the pH of the citric acid electroplating system is ≥7.

[0031] The titanium-based iridium-tantalum oxide coating anode provided by the application has a higher tantalum content than iridium content, and when applied in a neutral and slightly alkaline citric acid electroplating system, can not only maintain a good service life, but also effectively inhibit the accumulation and decomposition of complexing agents, neither accumulates too fast like stainless steel nor decomposes too fast like a common titanium-based iridium-tantalum oxide coating anode, thereby ensuring the deposition of main salt in the plating solution, the electroplating rate, improving the current efficiency by reducing the current density, and further improving the plating layer performance.

[0032] Advantages

[0033] The titanium-based iridium-tantalum oxide coating anode prepared by controlling the iridium-tantalum ratio has good electrical conductivity, corrosion resistance and stability, can effectively inhibit the decomposition of complexing agents in an alkaline citric acid electroplating system, maintain the stability of the plating solution components, thereby ensuring the plating layer quality, reducing the plating solution maintenance cost, and prolonging the service life. This is because Ta2O5 is an inert component with strong chemical stability, which can not only make the contact part of IrO2 and the titanium base stable, but also effectively inhibit the sharp increase of electrode potential when the oxygen evolution reaction occurs on the anode in the electrolyte containing organic matter, leading to the decomposition of organic matter, thereby stabilizing the plating solution components. The beta phase of tantalum sintered at 600-620 DEG C has high electrical conductivity, and the zircon in the brushing solution can refine the coating grain, fill the micro-cracks in the iridium-tantalum anode, improve the coating density, and avoid excessive coating cracking or electrical conductivity reduction.

[0034] The anode is prepared by a thermal decomposition brushing method, that is, the brushing solution is coated on the titanium base, and is made by solidification and thermal oxidation, which has the advantages of simple operation and easy production. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The figure is a diagram of the change of complexing agent with aging in the electroplating process of the titanium-based iridium-tantalum oxide coating anode in Example 1.

[0036] Figure 2 The figure is a diagram of the change of tungsten content and current efficiency with aging in the electroplating process of the titanium-based iridium-tantalum oxide coating anode in Example 1.

[0037] Figure 3 The figure is a diagram of the change of plating rate with aging in the electroplating process of the titanium-based iridium-tantalum oxide coating anode in Example 1.

[0038] Figure 4 The figure is a diagram of the change of complexing agent with aging in the electroplating process of the titanium-based iridium-tantalum oxide coating anode in Example 2.

[0039] Figure 5 The figure is a diagram of the change of tungsten content and current efficiency with aging in the electroplating process of the titanium-based iridium-tantalum oxide coating anode in Example 2.

[0040] Figure 6Figure 2 is a plot of plating rate versus age during the electroplating process for the titanium-based iridium tantalum oxide coated anode of Example 1.

[0041] Figure 7 Figure 4 is a plot of complexant versus age during the electroplating process for the conventional titanium-based iridium tantalum oxide coated anode of Comparative Example 1.

[0042] Figure 8 Figure 5 is a plot of bath color versus age during the electroplating process for the titanium-based iridium tantalum oxide coated anode of Comparative Example 1.

[0043] Figure 9 Figure 7 is a plot of complexant versus age during the electroplating process for the stainless steel anode of Comparative Example 2.

[0044] Figure 10 Figure 8 is a plot of tungsten content versus current efficiency in the coating of the stainless steel anode versus age during the electroplating process of Comparative Example 2.

[0045] Figure 11 Figure 9 is a plot of plating rate versus age during the electroplating process for the stainless steel anode of Comparative Example 2.

[0046] Figure 12 Figure 11 is a plot of complexant versus age during the electroplating process for the anode of Comparative Example 3.

[0047] Figure 13 Figure 12 is a plot of complexant versus age during the electroplating process for the anode of Comparative Example 4. DETAILED DESCRIPTION

[0048] The following examples further illustrate the control of complexant decomposition and build-up in an alkaline nickel tungsten citrate electroplating system for the titanium-based iridium tantalum oxide coated anodes prepared according to the present application.

[0049] Example 1

[0050] Step 1 The titanium substrate was cleaned (water rinsing followed by sanding with 800 grit sandpaper), grit blasted (the grit used was quartz sand having a grit size of 80-120, and the grit blasting pressure was 3.5 kg / cm 2 ), degreased (the titanium substrate was placed in an alkaline solution (comprising the following components: NaOH 40 g / L, Na2CO3 40 g / L, Na2PO4 40 g / L) for degreasing, and the degreasing temperature was controlled at 80°C), rinsed with water, pickled (hot dipping in an oxalic acid solution at 100°C for 1 h, the mass fraction of oxalic acid in the oxalic acid solution was 10%), rinsed with water, and dried.

[0051] Step 2 A 15% solution of pentachloride tantalum was brush coated onto the titanium substrate treated in Step 1, and sintered at 600°C for 20 min, repeated 4 times. After the last sintering, the temperature was maintained at 600°C for 1 h.

[0052] Step 3: Weigh tantalum pentachloride and chloroiridium hexahydrate at a tantalum to iridium mass ratio of 7:5, then weigh zirconium chloride (the mass of zirconium chloride is 5% of the total molar mass of tantalum pentachloride and chloroiridium hexahydrate), dissolve in concentrated hydrochloric acid and n-butanol (concentrated hydrochloric acid accounts for 15% of the total mass of the coating solution, and n-butanol accounts for 70% of the total mass of the coating solution), and sonicate for 40 min.

[0053] Step 4, Preparation of the titanium-based iridium-tantalum oxide coating anode: The coating solution prepared in Step 3 is brushed onto the titanium substrate treated in Step 2, sintered at 500℃ for 10 min, and then cooled. This process is repeated 10 times. After the last sintering, the substrate is held at 500℃ for 1 h.

[0054] Through the above process, a titanium-based iridium-tantalum oxide-coated anode with a tantalum content of 22.82% and an iridium content of 14.87% was prepared.

[0055] The titanium-based iridium-tantalum oxide-coated anode prepared in step 4 was used in a neutral to alkaline nickel-tungsten citric acid electroplating solution, wherein the neutral to alkaline nickel-tungsten citric acid electroplating solution contained the following main components: sodium tungstate 30 g / L, nickel sulfate 30 g / L, citric acid 30 g / L, sodium citrate 40 g / L, phosphorous acid 20 g / L, and ammonia water to adjust the pH to 7.1-7.3; at a current density of 8 A / dm³ -2 While aging the plating solution at 70°C, the changes in the complexing agent content, tungsten content of the plating layer, current efficiency, and plating rate in the plating solution are monitored. In the embodiments of the present invention, aging is started from the electroplating of the new solution (0Ah). In order to eliminate the interference of irrelevant factors, the electroplating solutions of all embodiments and comparative examples in the present invention have the same formula, and the aging cycle is the change of the first cycle being compared.

[0056] The change in the complexing agent content in Example 1 is as follows: Figure 1 As shown, the changes in tungsten content and current efficiency are as follows: Figure 2 As shown, the change in plating rate is as follows Figure 3 As shown.

[0057] Depend on Figure 1 It can be seen that the titanium-based iridium-tantalum oxide coating anode ages during the electroplating process, accumulating to 86.21 g / L at 400 Ah. From... Figure 2 It can be seen that the tungsten content of the coating is >19% during the service life, and the average current efficiency is approximately 26%. Figure 3 It can be seen that the plating rate is >15μm / h during the aging cycle.

[0058] Example 2

[0059] Step 1 is the same as in Example 1.

[0060] Step 2: Dissolve 15% tantalum pentachloride and brush it onto the titanium substrate treated in Step 1. Sinter at 610°C for 20 min, repeating 5 times. After the last sintering, hold at 610°C for 1 h.

[0061] Step 3: Weigh tantalum pentachloride and chloroiridic acid hexahydrate at a tantalum to iridium mass ratio of 6:4, then weigh zirconium chloride (the mass of zirconium chloride is 2% of the total molar mass of tantalum pentachloride and chloroiridic acid hexahydrate), dissolve them in concentrated hydrochloric acid and n-butanol (concentrated hydrochloric acid accounts for 10% of the total mass of the coating solution, and n-butanol accounts for 75% of the total mass of the coating solution), and sonicate for 30 minutes.

[0062] Step 4 is the same as in Example 1.

[0063] Through the above process, a titanium-based iridium-tantalum oxide-coated anode with a tantalum content of 18.84% and an iridium content of 10.35% was prepared.

[0064] The titanium-based iridium-tantalum oxide-coated anode prepared in step 4 was used in a neutral to alkaline nickel-tungsten citric acid electroplating solution, wherein the neutral to alkaline nickel-tungsten citric acid electroplating solution contained the following main components: sodium tungstate 30 g / L, nickel sulfate 30 g / L, citric acid 30 g / L, sodium citrate 40 g / L, phosphorous acid 20 g / L, and ammonia water to adjust the pH to 7.1-7.3; at a current density of 10 A / dm³. -2 The plating bath was aged at 75℃ while changes in the complexing agent content, tungsten content of the coating, current efficiency, and plating rate were monitored. Changes in the complexing agent content were observed as follows: Figure 4 As shown, the changes in tungsten content and current efficiency are as follows: Figure 5 As shown, the change in plating rate is as follows Figure 6 As shown.

[0065] Depend on Figure 4 It can be seen that the complexing agent in the titanium-based iridium-tantalum oxide coating anode gradually accumulates with aging, reaching 91.22 g / L at 400 Ah. Figure 5 It can be seen that the tungsten content of the coating is >22% during the service life, and the average current efficiency is approximately 25%. Figure 6 It can be seen that during the aging cycle, the plating rate is maintained within a range of >18μm / h.

[0066] Comparative Example 1

[0067] A conventional titanium-based iridium-tantalum oxide-coated anode purchased from the market will be used. The anode coating contains 7.53% tantalum and 12.89% iridium. The anode will be used at a current density of 10 A / dm³. -2 It was used in a neutral to slightly alkaline nickel-tungsten citric acid electroplating bath at 75℃ to age the plating bath while monitoring changes in the complexing agent content. The changes in the complexing agent content are as follows: Figure 7 As shown. Figure 8The color change of the plating solution.

[0068] Depend on Figure 7 It can be seen that with conventional titanium-based iridium-tantalum oxide coating anodes containing 7.53% tantalum and 12.89% iridium, the complexing agent decomposes during aging, reaching 18.27 g / L at 48 Ah. From Figure 8 It can be seen that the decomposition products seriously affect the state of the plating solution.

[0069] Comparative Example 2

[0070] Stainless steel anodes were used in a neutral to slightly alkaline nickel-tungsten citric acid electroplating bath at a current density of 10 A / dm³. -2 The plating bath was aged at 75℃ while the change in the complexing agent content was monitored. The change in complexing agent content was as follows: Figure 9 As shown. Changes in tungsten content and current efficiency are as follows. Figure 10 As shown, the change in plating rate is as follows Figure 11 As shown.

[0071] Depend on Figure 9 It can be seen that the complexing agent gradually accumulates in stainless steel as it ages, reaching 117.83 g / L at 200 Ah. Figure 10 It can be seen that the tungsten content of the coating is >16% during the service life, and the average current efficiency is approximately 22%. Figure 11 It can be seen that during the aging cycle, the plating rate drops significantly by more than 15 μm / h.

[0072] Comparative Example 3

[0073] A titanium-based iridium-tantalum oxide-coated anode with 13.84% tantalum and 12.32% iridium (which does not conform to the specification that the tantalum content is greater than 5% iridium content) was used at a current density of 8 A / dm². -2 It was used in a neutral to slightly alkaline nickel-tungsten citric acid electroplating bath at 70℃ to age the plating bath while monitoring changes in the complexing agent content. The changes in the complexing agent content are as follows: Figure 12 As shown.

[0074] Depend on Figure 12 It is known that when using a titanium-based iridium-tantalum oxide-coated anode with a tantalum content of 13.84% and an iridium content of 12.32%, the complexing agent accumulates during aging from 0 to 200 Ah. After 200 Ah, the complexing agent begins to decompose due to the exposure of the active sites of Ir.

[0075] Comparative Example 4

[0076] Except for step 3, which omits zirconium chloride, the other steps are the same as in Example 2, preparing a titanium-based iridium-tantalum oxide-coated anode with a tantalum content of 15.17% and an iridium content of 8.66%, under a current density of 10 A / dm³. -2It was used in a neutral to slightly alkaline nickel-tungsten citric acid electroplating bath at 75℃ to age the plating bath while monitoring changes in the complexing agent content. The changes in the complexing agent content are as follows: Figure 13 As shown.

[0077] Depend on Figure 13 It can be seen that in the titanium-based iridium-tantalum oxide-coated anode prepared in Comparative Example 4, the complexing agent accumulates during aging from 0 to 200 Ah. After 200 Ah, due to the cracking of the coating, more active sites of Ir are exposed, and the complexing agent begins to decompose.

Claims

1. A method of making a titanium-based iridium tantalum oxide coated anode, characterized by: It comprises the following steps: Step one The solution containing tantalum source A is brushed on the titanium substrate, and then sintering is carried out, and the brushing-sintering is repeated to obtain a tantalum-coated titanium substrate; Step two The iridium-tantalum oxide coating solution is brushed on the tantalum-coated titanium substrate, and then sintering is carried out, and the brushing-sintering is repeated to obtain the titanium substrate coated with iridium-tantalum oxide coating; The iridium-tantalum oxide coating solution contains tantalum source B, iridium source and zirconium source; In the iridium-tantalum oxide coating solution, the mass ratio of tantalum to iridium is 6-7:4-5.

2. The method of claim 1, wherein the method further comprises: The titanium substrate is first subjected to water washing, sandpaper polishing, sand blasting, oil removal, water washing, acid immersion, water washing and drying treatment in sequence.

3. The method of claim 2, wherein the method further comprises: The sand used in the sand blasting is quartz sand with a sand particle size of 80-120 mesh, and the pressure of the sand blasting is 3-4 kg / cm 2 ; The oil removal process is to place the titanium substrate in an alkaline solution to remove oil, and the temperature for oil removal is controlled at 70-80℃, and the alkaline solution comprises the following components: NaOH 30-50 g / L, Na2CO3 30-50 g / L, Na2PO4 30-50 g / L; The acid immersion process is to place the titanium substrate in an oxalic acid solution for heat immersion at 100-110℃ for 1-2h or in a hydrochloric acid solution for immersion at room temperature for 2-3h, and in the oxalic acid solution, the mass fraction of oxalic acid is 10-15%, and in the hydrochloric acid solution, the mass fraction of HCl is 30-38%.

4. The method for preparing a titanium-based iridium-tantalum oxide coated anode according to claim 1, characterized in that: In step one, the solution containing tantalum source A is a solution of tantalum pentachloride, and in the solution of tantalum pentachloride, the mass fraction of tantalum pentachloride is 10-15%.

5. The method of claim 1, wherein: the titanium-based iridium tantalum oxide coating anode is prepared by: forming a titanium-based anode; forming a tantalum oxide layer on the titanium-based anode; and forming an iridium oxide layer on the tantalum oxide layer. In step one, the solution containing tantalum source A is brushed on the titanium substrate, and then sintering is carried out, and the brushing-sintering is repeated 2-5 times, and the sintering temperature is 600-620℃, and the holding time for the last sintering is 1-2h, and the holding time for the other times of sintering is 20-30min.

6. The method of claim 1, wherein the method further comprises: In step two, in the iridium-tantalum oxide coating solution, the tantalum source B is tantalum pentachloride, the iridium source is chloroiridic acid hexahydrate, and the zirconium source is zirconium chloride; In the iridium-tantalum oxide coating solution, the amount of zirconium chloride added is 2%-5% of the total moles of tantalum pentachloride and chloroiridic acid hexahydrate.

7. The method of claim 1, wherein the method further comprises: depositing a layer of iridium on the titanium substrate; and annealing the titanium substrate and the layer of iridium. In step two, the process for obtaining the iridium-tantalum oxide coating solution is to add tantalum pentachloride, chloroiridic acid hexahydrate and zirconium chloride into a mixed solvent composed of hydrochloric acid and n-butanol, and then ultrasonic treatment is carried out for 30-60min to obtain the solution. In the iridium-tantalum oxide coating solution, the mass fraction of n-butanol is 60%-75%, and the mass fraction of HCl is 5%-15%.

8. The method of claim 1, wherein: the titanium-based iridium tantalum oxide coating anode is prepared by: forming a titanium-based anode; forming a tantalum oxide layer on the titanium-based anode; and forming an iridium oxide layer on the tantalum oxide layer. In step two, the iridium-tantalum oxide coating solution is brushed on the tantalum-coated titanium substrate, and then sintering is carried out, and the brushing-sintering is repeated 10-15 times, and the temperature for the last sintering is 450-520℃, and the holding time for the last sintering is 1-2h, and the temperature for the other times of sintering is 450-530℃, and the holding time for the other times of sintering is 10-30min.

9. A titanium-based iridium tantalum oxide coated anode prepared according to the method of any one of claims 1 to 8, characterized in that: In the titanium substrate-iridium-tantalum oxide coating anode, the mass fraction of tantalum is 13%-56%, and the mass fraction of iridium is 7%-20%, and the mass fraction of tantalum is more than 5% higher than the mass fraction of iridium.

10. Use of a titanium-based iridium tantalum oxide coated anode produced according to the method of any one of claims 1 to 8, characterized in that: The titanium substrate-iridium-tantalum oxide coating anode is applied to a citric acid electroplating system, and the pH of the citric acid electroplating system is greater than or equal to 7.

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