A titanium-based iridium tantalum oxide coating anode and a preparation method and application thereof

Abstract

The application discloses a titanium base-iridium tantalum oxide coating anode and a preparation method and application thereof, and belongs to the technical field of anode preparation. The preparation process of the titanium base-iridium tantalum oxide coating anode is as follows: a solution containing a tantalum source A is brushed on a titanium base body, and then sintering is carried out; the brushing-sintering is repeated to obtain a tantalum-coated titanium base body; an iridium tantalum oxide coating liquid is brushed on the tantalum-coated titanium base body, and then sintering is carried out; and the brushing-sintering is repeated to obtain the titanium base-iridium tantalum oxide coating anode. The iridium tantalum oxide coating liquid contains a tantalum source B, an iridium source and a zirconium source. In the iridium tantalum oxide coating liquid, the mass ratio of the tantalum to the iridium is 6-7:4-5. According to the preparation method, the content of the tantalum in the titanium base-iridium tantalum oxide coating anode is more than 5% higher than the content of the iridium, the decomposition of a complexing agent can be effectively inhibited in an alkaline citric acid electroplating system, the composition of a plating solution is maintained stable, the plating layer quality is ensured, the maintenance cost of the plating solution is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of anode preparation technology, specifically relating to a titanium-based iridium-tantalum oxide coated anode, its preparation method, and its application. Background Technology

[0002] In citric acid electroplating systems, complexing agents play a role in controlling metal ion concentration, improving dispersion, and enhancing coverage. Commonly used insoluble anodes in alkaline citric acid electroplating systems include stainless steel, platinum, and titanium-based coated anodes. While stainless steel anodes are inexpensive, they exhibit slight dissolution in alkaline plating solutions. Furthermore, as the plating solution ages, the complexing agent can accumulate excessively, leading to over-complexation with the main salt metal ions. This reduces the number of free metal ions, severely impacting the deposition of the main salt, reducing current efficiency, decreasing the plating rate, and ultimately affecting coating performance. Platinum anodes and other precious metal anodes are limited by their high price, thus titanium-based coated anodes are currently the preferred choice. Among these, oxygen-evolving titanium-based iridium-tantalum oxide coated anodes (Ti / IrO2+Ta2O5) pose no risk of dissolution and plating solution contamination compared to stainless steel anodes, and are relatively inexpensive than precious metal anodes, making them a commonly used electroplating anode.

[0003] Currently available titanium-based iridium-tantalum oxide coated anodes are mainly suitable for acidic electroplating processes, such as chromium and nickel plating. In iridium-tantalum oxide coatings, the iridium-tantalum molar ratio is controlled at 6:4-7:3. Excessive tantalum content can cause numerous large cracks in the coating. Oxygen released during electrolysis can easily diffuse through these cracks into the titanium substrate, forming a non-conductive titanium oxide passivation film. This not only hinders current conduction but also damages the adhesion between the coating and the substrate, leading to coating peeling. The aforementioned ratio retains the role of tantalum oxide in enhancing coating stability while ensuring sufficient active sites for iridium oxide. However, these titanium-based iridium-tantalum oxide coated anodes are not suitable for alkaline electroplating processes. In alkaline electroplating, the alkaline solution accelerates the dissolution or structural destruction of iridium and tantalum oxides in the coating, significantly shortening the anode's lifespan. Furthermore, the strong catalytic effect of the noble metal (Ir) in the anode can cause the complexing agent to decompose too quickly, leading to an imbalance in the plating solution, reduced current efficiency, and affecting the coating quality and the lifespan of the plating solution. Furthermore, the decomposition products generated by the large-scale decomposition of the complexing agent can adversely affect the performance of the coating. Therefore, the plating solution needs to be adsorbed and filtered regularly, which leads to a decrease in production efficiency. Summary of the Invention

[0004] To address the aforementioned problems, the first objective of this invention is to provide a method for preparing a titanium-based iridium-tantalum oxide-coated 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] In the preferred embodiment, in step one, the titanium substrate is first subjected to water washing, sandpaper polishing, sandblasting, degreasing, water washing, acid immersion, water washing, and drying. Through the above pretreatment process, the oxide film on the surface of the titanium alloy can be effectively removed, forming a more uniform coating surface with suitable roughness, greatly improving the adhesion between the titanium alloy workpiece and the coating. In actual operation, 800-grit sandpaper is used for polishing.

[0017] In a further preferred embodiment, the sand used for sandblasting is quartz sand with a particle size of 80-120 mesh, and the sandblasting pressure is 3-4 kg / cm². 2 .

[0018] By controlling the sandblasting conditions within the above range, the optimal roughness is obtained, and the final coating exhibits the best bonding performance.

[0019] In a further preferred embodiment, the degreasing process involves placing the titanium substrate in an alkaline solution to remove oil, controlling the degreasing temperature at 70-80°C. The alkaline solution comprises the following components: NaOH 30-50 g / L, Na2CO3 30-50 g / L, and Na2PO4 30-50 g / L.

[0020] In a further preferred embodiment, the acid leaching process involves placing the titanium substrate in an oxalic acid solution at 100-110°C for 1-2 hours or in a hydrochloric acid solution at room temperature for 2-3 hours. The oxalic acid solution contains 10-15% oxalic acid by mass, and the hydrochloric acid solution contains 30-38% HCl by mass.

[0021] In the preferred embodiment, in step one, the solution containing tantalum source A is a tantalum pentachloride solution, wherein the mass fraction of tantalum pentachloride in the tantalum pentachloride solution is 10-15%. Optimal performance is achieved when the mass fraction of tantalum pentachloride in the solution containing tantalum source A is controlled within this range. If the mass fraction is too high, the coating will be uneven after sintering; if the mass fraction is too low, the coating will be too thin, resulting in incomplete coating and affecting corrosion resistance.

[0022] In the preferred embodiment, in step one, a solution containing tantalum source A is brushed onto a titanium substrate and then sintered. The brushing-sintering process is repeated 2 to 5 times, preferably 4 to 5 times. The sintering temperature is 600 to 620°C. The holding time for the last sintering is 1 to 2 hours, and the holding time for the remaining sinterings is 20 to 30 minutes.

[0023] In this invention, multiple coatings with a solution containing tantalum source A ensure the thickness and density of the coating. The intermediate holding time is controlled at 20-30 minutes to serve as a transition, allowing the tantalum source to transform into oxide and improving growth efficiency. The final holding at 600-620℃ for an extended period completes the crystal transformation. Therefore, the holding temperature needs to be effectively controlled. If the temperature is too low, an α phase will form, reducing conductivity, while if it is too high, the density will decrease.

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

[0025] In a further preferred embodiment, the amount of zirconium chloride added to the iridium-tantalum oxide coating solution is 2% to 5% of the total molar amount of tantalum pentachloride and chloroiridium hexahydrate. Controlling the amount of zirconium source added within this range can effectively refine the coating grains, fill microcracks in the iridium-tantalum anode, improve the coating density, and avoid excessive addition that could lead to coating cracking or decreased conductivity.

[0026] In the preferred embodiment, in step two, the process of obtaining the iridium-tantalum oxide coating solution is as follows: tantalum pentachloride, chloroiridium hexahydrate, and zirconium chloride are added to a mixed solvent composed of hydrochloric acid and n-butanol, and ultrasonically treated for 30-60 minutes to obtain the solution.

[0027] In a further preferred embodiment, the mass fraction of n-butanol in the iridium-tantalum oxide coating solution is 60%~75%, and the mass fraction of HCl is 5%~15%.

[0028] In the preferred embodiment, in step two, the iridium-tantalum oxide coating solution is brushed onto the tantalum-titanium substrate, followed by sintering. This brush-coating-sintering process is repeated 10-15 times. The temperature of the final sintering is 450-520℃, and the holding time during the final sintering is 1-2 hours. The temperature of the remaining sintering cycles is 450-530℃, and the holding time during the remaining sintering cycles is 10-30 minutes. Using the above coating-sintering process yields the coating with the best performance.

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

[0030] The present invention also provides the application of the titanium-based iridium-tantalum oxide-coated anode prepared by the above preparation method, wherein the titanium-based iridium-tantalum oxide-coated anode is applied in a citric acid electroplating system, wherein the citric acid electroplating system has a pH ≥ 7.

[0031] The titanium-based iridium-tantalum oxide coating provided by this invention has a higher tantalum content than iridium content on the anode. When applied to a neutral to slightly alkaline citric acid electroplating system, it can maintain a good service life and effectively inhibit the accumulation and decomposition of complexing agents. It does not accumulate too quickly like stainless steel, nor does it decompose too quickly like common titanium-based iridium-tantalum oxide coatings on the anode. This ensures the deposition of the main salt in the plating solution and the electroplating rate. By reducing the current density and increasing the current efficiency, the performance of the coating can be improved.

[0032] Beneficial effects

[0033] This invention prepares an anode for a titanium-based iridium-tantalum oxide coating by controlling the iridium-tantalum ratio. This anode exhibits excellent conductivity, corrosion resistance, and stability. 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 ensuring 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 occurs on the anode in an electrolyte containing organic matter, leading to the decomposition of organic matter. This stabilizes the plating solution composition. The tantalum β phase formed by sintering at 600-620℃ has high conductivity, while the zirconium in the coating solution refines the coating grains, fills microcracks in the iridium-tantalum anode, and improves the coating density, preventing excessive zirconium from causing coating cracking or decreased conductivity.

[0034] This invention uses a thermal decomposition coating method to prepare an anode, which involves coating a solution onto a titanium substrate, followed by curing and thermal oxidation. This method has the advantages of being simple to operate and easy to produce. Attached Figure Description

[0035] Figure 1 The graph shows the change of complexing agent with aging during the electroplating process of the titanium-based iridium-tantalum oxide-coated anode in Example 1.

[0036] Figure 2 The graph shows the changes in tungsten content and current efficiency with aging in the titanium-based iridium-tantalum oxide-coated anode during the electroplating process in Example 1.

[0037] Figure 3 The graph shows the change in plating rate as the anode with titanium-based iridium-tantalum oxide coating in Example 1 during the electroplating process.

[0038] Figure 4 The graph shows the change of complexing agent with aging during the electroplating process of the titanium-based iridium-tantalum oxide-coated anode in Example 2.

[0039] Figure 5 The graph shows the changes in tungsten content and current efficiency with aging in the titanium-based iridium-tantalum oxide-coated anode during the electroplating process in Example 2.

[0040] Figure 6The graph shows the change in plating rate with aging during the electroplating process of the titanium-based iridium-tantalum oxide-coated anode in Example 2.

[0041] Figure 7 The graph shows the change of complexing agent with aging during the electroplating process of the conventional titanium-based iridium-tantalum oxide coated anode in Comparative Example 1.

[0042] Figure 8 The graph shows the color change of the titanium-based iridium-tantalum oxide-coated anode in Comparative Example 1 during the electroplating process as the plating solution ages.

[0043] Figure 9 The graph shows the changes in the stainless steel anolyte complexing agent during the electroplating process in Comparative Example 2 as it ages.

[0044] Figure 10 The graph shows the changes in tungsten content and current efficiency with aging in the stainless steel anodic coating of Comparative Example 2 during the electroplating process.

[0045] Figure 11 The graph shows the change in plating rate of the stainless steel anode during electroplating as it ages in Comparative Example 2.

[0046] Figure 12 The graph shows the change of complexing agent in the anode of Comparative Example 3 during the electroplating process as the anode ages.

[0047] Figure 13 The graph shows the change of the anolyte complexing agent in Comparative Example 4 with aging. Detailed Implementation

[0048] The following examples further illustrate the control effect of the titanium-based iridium-tantalum oxide-coated anode prepared according to the present invention on the decomposition and accumulation of complexing agents in an alkaline nickel-tungsten citric acid electroplating system.

[0049] Example 1

[0050] Step 1: Clean the titanium substrate (first wash with water, then polish with 800-grit sandpaper) and sandblast (use 80-120 mesh quartz sand, sandblasting pressure is 3.5 kg / cm²). 2 The process includes degreasing (the titanium substrate is placed in an alkaline solution (containing the following components: NaOH 40 g / L, Na2CO3 40 g / L, Na2PO4 40 g / L) to remove oil, with the degreasing temperature controlled at 80℃), water washing, acid washing (hot soaking in an oxalic acid solution at 100℃ for 1 hour, with the oxalic acid mass fraction in the solution being 10%), water washing, and drying.

[0051] Step 2: Dissolve 15% tantalum pentachloride and brush it onto the titanium substrate treated in Step 1. Sinter at 600°C for 20 min, repeating 4 times. After the last sintering, hold 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 8This refers to the 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 the plating rate drops significantly during the aging cycle, 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 for preparing a titanium-based iridium-tantalum oxide coated anode, characterized in that: Includes the following steps: Step 1 A solution containing tantalum source A is brushed onto a titanium substrate and then sintered. The brushing-sintering process is repeated 2 to 5 times. The sintering temperature is 600 to 620°C. The holding time for the last sintering is 1 to 2 hours, and the holding time for the remaining sinterings is 20 to 30 minutes. A tantalum-coated titanium substrate is obtained. Step Two 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. 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; In the iridium-tantalum oxide coating solution, tantalum source B is tantalum pentachloride, iridium source is chloroiridium hexahydrate, and zirconium source is zirconium chloride; In the iridium-tantalum oxide coating solution, the amount of zirconium chloride added is 2% to 5% of the total molar amount of tantalum pentachloride and chloroiridium hexahydrate.

2. The method for preparing a titanium-based iridium-tantalum oxide coated anode according to claim 1, characterized in that: The titanium substrate is first subjected to water washing, sanding, sandblasting, degreasing, water washing, acid immersion, water washing and drying in sequence.

3. The method for preparing a titanium-based iridium-tantalum oxide coated anode according to claim 2, characterized in that: The sand used for sandblasting is quartz sand with a particle size of 80-120 mesh, and the sandblasting pressure is 3-4 kg / cm². 2 ; The degreasing process involves placing the titanium substrate in an alkaline solution to remove oil, controlling the degreasing temperature at 70-80℃. The alkaline solution contains the following components: NaOH 30-50 g / L, Na2CO3 30-50 g / L, and Na2PO4 30-50 g / L. The acid leaching process involves placing the titanium substrate in an oxalic acid solution at 100-110°C for 1-2 hours or in a hydrochloric acid solution at room temperature for 2-3 hours. The oxalic acid solution contains 10-15% oxalic acid by mass and 30-38% HCl by mass.

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 tantalum pentachloride solution, in which the mass fraction of tantalum pentachloride is 10-15%.

5. The method for preparing a titanium-based iridium-tantalum oxide coated anode according to claim 1, characterized in that: In step two, the process of obtaining the iridium-tantalum oxide coating solution is as follows: tantalum pentachloride, chloroiridium hexahydrate and zirconium chloride are added to a mixed solvent composed of hydrochloric acid and n-butanol, and ultrasonically treated for 30-60 minutes 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%.

6. The method for preparing a titanium-based iridium-tantalum oxide coated anode according to claim 1, characterized in that: In step two, the iridium-tantalum oxide coating liquid is brushed onto the tantalum-titanium substrate and then sintered. The brushing-sintering process is repeated 10 to 15 times. The temperature of the last sintering is 450 to 520°C and the holding time during the last sintering is 1 to 2 hours. The temperature of the remaining sinterings is 450 to 530°C and the holding time during the remaining sinterings is 10 to 30 minutes.

7. The titanium-based iridium-tantalum oxide-coated anode prepared by the method for preparing a titanium-based iridium-tantalum oxide-coated anode according to any one of claims 1-6, characterized in that: In the titanium-based iridium-tantalum oxide coating anode, 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% greater than the mass fraction of iridium.

8. The application of the titanium-based iridium-tantalum oxide-coated anode prepared by the method for preparing a titanium-based iridium-tantalum oxide-coated anode according to any one of claims 1-6, characterized in that: The titanium-based iridium-tantalum oxide coating anode is applied to a citric acid electroplating system, wherein the pH of the citric acid electroplating system is ≥7.

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