Double-layer titanium mesh anode for PCB electroplating and preparation method thereof

Abstract

The application relates to a double-layer titanium mesh anode for PCB electroplating and a preparation method thereof, and belongs to the technical field of titanium anode preparation. The double-layer titanium mesh anode comprises a first titanium mesh layer and a second titanium mesh layer, and a gap of 0.5-3 mm is kept between the two layers; wherein the mesh hole aperture of the first titanium mesh layer is larger than that of the second titanium mesh layer, and the mesh holes of the first titanium mesh layer and the second titanium mesh layer are distributed in a staggered mode. The prepared anode has excellent stability and service life, and helps to improve the quality of a plating layer.

Description

Technical Field

[0001] This invention belongs to the field of titanium anode preparation technology, and relates to a double-layer titanium mesh anode for PCB electroplating and its preparation method. Background Technology

[0002] PCB electroplating is a critical process in printed circuit board manufacturing, and its quality directly determines the conductivity reliability, signal transmission performance, and yield of the circuit board. In PCB electroplating production, the selection and structural design of the anode material have a crucial impact on plating uniformity, coating quality, and production efficiency. Currently, PCB electroplating production lines widely use insoluble anodes (such as titanium-based coated anodes) to replace traditional phosphorus copper ball soluble anodes, solving problems such as uneven copper ball dissolution, anode sludge contamination, and frequent copper ball addition. However, existing insoluble titanium anodes still face the following technical challenges in practical applications that urgently need to be addressed.

[0003] First, the negative effects of oxygen evolution bubbles are difficult to control effectively; second, the single anode structure makes it difficult to balance current distribution and bubble dissipation; third, the management of electroplating additives relies on external replenishment and lacks precise control methods; fourth, the titanium mesh pretreatment process is rough, limiting the coating adhesion and lifespan.

[0004] Therefore, there is an urgent need to develop an anode for PCB electroplating that can effectively control the behavior of oxygen evolution bubbles, thereby improving lifespan and stability. Summary of the Invention

[0005] The purpose of this invention is to provide a double-layer titanium mesh anode for PCB electroplating and its preparation method. The anode prepared by this invention has excellent stability and lifespan, which helps to improve the quality of the plating layer.

[0006] The objective of this invention can be achieved through the following technical solutions: A double-layer titanium mesh anode for PCB electroplating, the double-layer titanium mesh anode comprising a first titanium mesh layer and a second titanium mesh layer; The mesh size of the first titanium mesh layer is larger than that of the second titanium mesh layer, and there is a misalignment between the meshes of the first and second titanium mesh layers.

[0007] A method for preparing the double-layer titanium mesh anode for PCB electroplating as described in claim 1, comprising the following specific steps: S1. Titanium mesh pretreatment: The titanium mesh was subjected to alkaline washing and degreasing with 10wt% sodium hydroxide solution, ultrasonic-assisted acid etching and electrochemical activation treatment in sequence to obtain a pretreated titanium mesh. S2, MOF self-assembly: S2.1 Preparation of the first titanium mesh layer: Chloroiridic acid and tantalum pentachloride were added to n-butanol to prepare a precursor solution with a total metal ion concentration of 0.18~0.22mol / L. The solution was stirred to obtain a coating solution. The coating solution was uniformly coated on both sides of the titanium mesh, dried at 110~120℃ for 10min, and then placed in a muffle furnace for heat treatment in air atmosphere to obtain the first titanium mesh layer. S2.2, Preparation of the second titanium mesh layer: Cobalt dichloride hexahydrate was mixed with anhydrous ethanol to prepare a 5 mmol / L metal solution; 2-aminoterephthalic acid and terephthalic acid were mixed and added to N,N-dimethylformamide to prepare a 5-6 mmol / L organic ligand solution, and then an equal volume of anhydrous ethanol was added and mixed evenly to obtain mixture A. The pretreated titanium mesh is first immersed in the metal solution for 30-35 minutes, then rinsed with anhydrous ethanol for 30-40 seconds, then immersed in the mixture A for 30-35 minutes, then rinsed with anhydrous ethanol for 30-40 seconds; the above immersion and rinsing steps are repeated 20 times, and the second titanium mesh layer is obtained after heat treatment. S3, Double-layer anode assembly: The first titanium mesh layer and the second titanium mesh layer are fixedly connected, with a preset interval between the two layers and the mesh holes are staggered.

[0008] As a preferred embodiment of the present invention, in step S1, the ultrasonic-assisted acid etching process is as follows: The titanium mesh was immersed in a 1:1 mixture of 18wt% hydrochloric acid and saturated oxalic acid and subjected to ultrasonic treatment at 40-45kHz at 90℃ for 2 hours.

[0009] As a preferred technical solution of the present invention, in step S1, the electrochemical activation treatment is as follows: using an acid-etched titanium mesh as the working electrode, applying an anodic potential of 1.5 V in a 10wt% oxalic acid solution, and performing constant potential polarization treatment for 30 min.

[0010] As a preferred technical solution of the present invention, in step S2.1, the specific process of the heat treatment is as follows: first, the temperature is raised to 400~415℃ at a heating rate of 3~5℃ / min and held for 10~15min, then the temperature is raised to 490~505℃ at the same rate and held for 30min, then the furnace is naturally cooled, and finally the final heat treatment is carried out at 500℃ for 1h.

[0011] As a preferred embodiment of the present invention, in step S2.1, the molar ratio of Ir to Ta in the precursor solution is (7~7.5):3.

[0012] As a preferred embodiment of the present invention, in step S2.1, the loading of metallic Ir in the coating on the first titanium mesh layer is 20~25 g / m.2 .

[0013] As a preferred embodiment of the present invention, in step S2.2, the molar ratio of 2-aminoterephthalic acid to terephthalic acid is 3:(7~8).

[0014] As a preferred technical solution of the present invention, in step S2.2, the heat treatment further includes, after repeating the operation every 5 times, placing the titanium mesh in a vacuum drying oven at 60°C for 2 hours, after 20 times, placing the titanium mesh in a vacuum drying oven at 110~120°C for 12 hours, and then placing it in a tube furnace, heating it to 300~320°C at 2°C / min under argon protection and holding it for 2 hours.

[0015] As a preferred embodiment of the present invention, in step S3, the double-layer anode is further activated in situ. Specifically, the assembled anode is immersed in a 0.3 mol / L sulfuric acid solution at a concentration of 30 mA / cm². 2 The current density was anodicly polarized for 45 minutes.

[0016] This invention employs a double-layer titanium mesh structure, wherein the first titanium mesh layer (inner layer) is an IrO2-Ta2O5 coating with high oxygen evolution activity, which is responsible for the main electrochemical reaction and generates oxygen; the second titanium mesh layer (outer layer) is formed by alternately immersing the pretreated titanium mesh in metal ion solution and organic ligand solution, and growing MOF film on the surface of the titanium mesh through layer-by-layer self-assembly.

[0017] By setting the inner layer mesh aperture to be larger than the outer layer mesh aperture, and coordinating the staggered distribution of the two layers of mesh in the projection direction, the larger pores in the inner layer facilitate the rapid escape of oxygen bubbles, preventing the gas curtain shielding phenomenon commonly seen on traditional anode surfaces; while the smaller pores in the outer layer make the electric field distribution more uniform and delicate, significantly improving electroplating uniformity. At the same time, maintaining a uniform gap between the two mesh layers ensures smooth electrolyte flow, reduces concentration polarization, and prevents bubbles from accumulating between the two layers.

[0018] This invention loads an Ir-Ta binary oxide coating onto the inner surface. By optimizing the molar ratio of Ir to Ta and employing a stepped sintering process, a catalytic coating exhibiting both high oxygen evolution activity and excellent corrosion resistance is obtained, effectively reducing anodic overpotential and achieving energy saving and consumption reduction. An amino-functionalized Co-MOF film is grown on the surface of the second titanium mesh layer using a layer-by-layer self-assembly method, followed by partial carbonization and in-situ electrochemical activation. This MOF film possesses a uniform nanoporous structure, capable of capturing micron-sized bubbles generated by the inner mesh, forming a uniform and dense gas curtain on the anode surface, thus solving the problem of uneven bubble size distribution in traditional anodes. Simultaneously, the amino functional groups introduced into the MOF film can bind organic additive molecules in the electroplating solution through electrostatic adsorption or coordination, achieving slow release of additives during electroplating. This improves anode bubble behavior while simultaneously optimizing the microscopic smoothness of the cathode coating. The cathode film formation process can be controlled through the anode material, thereby improving electroplating quality.

[0019] This invention utilizes a pretreatment process combining ultrasonic-assisted acid etching and electrochemical activation to construct a composite structure of "micron-pitted-nanoporous" structures on the surface of a titanium mesh. This structure forms a strong anchoring effect with subsequent coatings, improving coating adhesion. A stepped gradient sintering process eliminates internal stress in the inner coating layer, extending the anode's lifespan. The layer-by-layer self-assembly process combined with intermediate drying during MOF growth ensures the density and uniformity of the film. Post-assembly in-situ electrochemical activation treatment enhances the activity and hydrophilicity of the outer MOF film.

[0020] The beneficial effects of this invention are: This invention employs a double-layer titanium mesh design. The first titanium mesh layer exhibits high oxygen evolution activity and has a pore size gradient that is larger at the inside and smaller at the outside. The large pores in the first titanium mesh layer facilitate rapid gas escape. The small pores in the second titanium mesh layer result in a more uniform electric field distribution, improving electroplating uniformity. The staggered mesh distribution further enhances the uniformity of the current density distribution. The anode prepared by this invention exhibits excellent stability and lifespan, helping to improve the quality of the coating. Detailed Implementation

[0021] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0022] It should be noted that, unless otherwise specified, the present invention does not specifically limit the source of the raw materials used in the following embodiments. Commercially available products or products prepared by conventional preparation methods that are well known to those skilled in the art can be used. Experimental methods that do not specify specific conditions are all conventional methods and conventional conditions well known in the art.

[0023] The titanium mesh used below is industrial pure titanium TA1 woven mesh.

[0024] Example 1 S1. Titanium mesh pretreatment: The titanium mesh was soaked in a 10wt% sodium hydroxide solution for 30 min, and then immersed in a 1:1 mixture of 18wt% hydrochloric acid and saturated oxalic acid. It was then subjected to ultrasonic treatment at 42kHz at 90℃ for 2 h. The acid-etched titanium mesh was used as the working electrode, and an anodic potential of 1.5 V (vs. SCE) was applied in a 10wt% oxalic acid solution. The constant potential polarization treatment was performed for 30 min to obtain the pretreated titanium mesh. S2, MOF self-assembly: S2.1 Preparation of the first titanium mesh layer: Irchloroiridic acid and tantalum pentachloride were added to n-butanol to prepare a precursor solution with a total metal ion concentration of 0.2 mol / L. The molar ratio of Ir to Ta in the precursor solution was 7.3:3. Concentrated hydrochloric acid was added, with 1 mL of 36% (w / w) concentrated hydrochloric acid added per 100 mL of the precursor solution. The mixture was stirred for 2 h to obtain a coating solution. The coating solution was uniformly applied to both sides of a titanium mesh and dried at 120 °C for 10 min. Then, the mesh was placed in a muffle furnace under air atmosphere and heated to 405 °C at a rate of 4 °C / min and held for 15 min. The temperature was then increased to 500 °C at the same rate and held for 30 min. The mesh was then allowed to cool naturally in the furnace and finally held at 500 °C for 1 h to obtain the first titanium mesh layer. The loading of Ir metal in the coating of the first titanium mesh layer was 22 g / m³. 2 .

[0025] S2.2, Preparation of the second titanium mesh layer: Cobalt dichloride hexahydrate was mixed with anhydrous ethanol to prepare a 5 mmol / L metal solution; 2-aminoterephthalic acid and terephthalic acid were mixed in a molar ratio of 3:7.5 and dissolved in N,N-dimethylformamide to prepare a 5 mmol / L organic ligand solution, and then an equal volume of anhydrous ethanol was added and mixed evenly to obtain mixture A. The pretreated titanium mesh was first immersed in a metal solution for 32 minutes, then rinsed with anhydrous ethanol for 35 seconds, and then immersed in mixed solution A for 33 minutes. It was then rinsed with anhydrous ethanol for 35 seconds. The above immersion and rinsing steps were repeated 20 times. After every 5 times, the titanium mesh was placed in a vacuum drying oven at 60°C for 2 hours. After 20 times, the titanium mesh was placed in a vacuum drying oven at 115°C for 12 hours. Then it was placed in a tube furnace and heated to 300~320°C at 2°C / min under argon protection and held for 2 hours to obtain the second titanium mesh layer. S3, Double-layer anode assembly: The first and second titanium mesh layers were assembled and fixed together using screws and nuts, with the mesh openings of the two meshes staggered. The assembled anode was then immersed in a 0.3 mol / L sulfuric acid solution at 30 mA / cm².2 The current density was anodicly polarized for 45 minutes, and then rinsed with deionized water.

[0026] Example 2 S1. Titanium mesh pretreatment: The titanium mesh was soaked in a 10wt% sodium hydroxide solution for 30 min, and then immersed in a 1:1 mixture of 18wt% hydrochloric acid and saturated oxalic acid. It was then subjected to ultrasonic treatment at 40 kHz at 90 °C for 2 h. The acid-etched titanium mesh was used as the working electrode, and an anodic potential of 1.5 V (vs. SCE) was applied in a 10wt% oxalic acid solution. The titanium mesh was subjected to constant potential polarization treatment for 30 min to obtain the pretreated titanium mesh. S2, MOF self-assembly: S2.1 Preparation of the first titanium mesh layer: Irchloroiridic acid and tantalum pentachloride were added to n-butanol to prepare a precursor solution with a total metal ion concentration of 0.18 mol / L. The molar ratio of Ir to Ta in the precursor solution was 7:3. Concentrated hydrochloric acid was added, with 1 mL of 36% (w / w) concentrated hydrochloric acid added per 100 mL of precursor solution. The mixture was stirred for 2 h to obtain a coating solution. The coating solution was uniformly coated on both sides of a titanium mesh and dried at 120 °C for 10 min. Then, the mesh was placed in a muffle furnace and heated to 400 °C at a rate of 3 °C / min and held for 10 min. The temperature was then increased to 490–505 °C at the same rate and held for 30 min. The mesh was then allowed to cool naturally in the furnace and finally held at 500 °C for 1 h to obtain the first titanium mesh layer. The loading of Ir metal in the coating of the first titanium mesh layer was 20 g / m². 2 .

[0027] S2.2, Preparation of the second titanium mesh layer: Cobalt dichloride hexahydrate was mixed with anhydrous ethanol to prepare a 5 mmol / L metal solution; 2-aminoterephthalic acid and terephthalic acid were mixed in a molar ratio of 3:7 and dissolved in N,N-dimethylformamide to prepare a 5 mmol / L organic ligand solution, and then an equal volume of anhydrous ethanol was added and mixed evenly to obtain mixture A. The pretreated titanium mesh was first immersed in a metal solution for 30 minutes, then rinsed with anhydrous ethanol for 30 seconds, and then immersed in mixed solution A for 30 minutes. The immersion and rinsing steps were repeated 20 times. After every 5 times, the titanium mesh was placed in a vacuum drying oven at 60°C for 2 hours. After 20 times, the titanium mesh was placed in a vacuum drying oven at 110°C for 12 hours. Then, it was placed in a tube furnace and heated to 300°C at 2°C / min under argon protection and held for 2 hours to obtain the second titanium mesh layer. S3, Double-layer anode assembly: The first and second titanium mesh layers were assembled and fixed together using screws and nuts, with the mesh openings of the two meshes staggered. The assembled anode was then immersed in a 0.3 mol / L sulfuric acid solution at 30 mA / cm². 2 The current density was anodicly polarized for 45 minutes.

[0028] Example 3 S1. Titanium mesh pretreatment: The titanium mesh was soaked in a 10wt% sodium hydroxide solution for 30 min, and then immersed in a 1:1 mixture of 18wt% hydrochloric acid and saturated oxalic acid. It was then subjected to ultrasonic treatment at 45 kHz at 90℃ for 2 h. The acid-etched titanium mesh was used as the working electrode, and an anodic potential of 1.5 V (vs. SCE) was applied in a 10wt% oxalic acid solution. The titanium mesh was subjected to constant potential polarization treatment for 30 min to obtain the pretreated titanium mesh. S2, MOF self-assembly: S2.1 Preparation of the first titanium mesh layer: Chloroiridic acid and tantalum pentachloride were added to n-butanol to prepare a precursor solution with a total metal ion concentration of 0.22 mol / L. The molar ratio of Ir to Ta in the precursor solution was 7.5:3. Concentrated hydrochloric acid was added, with 1 mL of 36% (w / w) concentrated hydrochloric acid added per 100 mL of the precursor solution. The mixture was stirred for 2 h to obtain a coating solution. The coating solution was uniformly coated on both sides of a titanium mesh and dried at 120 °C for 10 min. Then, the mesh was placed in a muffle furnace under air atmosphere and heated to 415 °C at a rate of 5 °C / min and held for 15 min. The temperature was then increased to 505 °C at the same rate and held for 30 min. The mesh was then allowed to cool naturally in the furnace and finally held at 500 °C for 1 h to obtain the first titanium mesh layer. The loading of Ir in the coating of the first titanium mesh layer was 25 g / m². 2 .

[0029] S2.2, Preparation of the second titanium mesh layer: Cobalt dichloride hexahydrate was mixed with anhydrous ethanol to prepare a 5 mmol / L metal solution; 2-aminoterephthalic acid and terephthalic acid were mixed in a molar ratio of 3:8 and dissolved in N,N-dimethylformamide to prepare a 5 mmol / L organic ligand solution, and then an equal volume of anhydrous ethanol was added and mixed evenly to obtain mixture A. The pretreated titanium mesh was first immersed in a metal solution for 30 minutes, then rinsed with anhydrous ethanol for 30 seconds, and then immersed in mixed solution A for 30 minutes. The immersion and rinsing steps were repeated 20 times. After every 5 times, the titanium mesh was placed in a vacuum drying oven at 60°C for 2 hours. After 20 times, the titanium mesh was placed in a vacuum drying oven at 120°C for 12 hours. Then, it was placed in a tube furnace and heated to 320°C at 2°C / min under argon protection and held for 2 hours to obtain the second titanium mesh layer. S3, Double-layer anode assembly: The first and second titanium mesh layers were assembled and fixed together using screws and nuts, with the mesh openings of the two meshes staggered. The assembled anode was then immersed in a 0.3 mol / L sulfuric acid solution at 30 mA / cm². 2 The current density was anodicly polarized for 45 minutes.

[0030] Example 4 It is basically the same as Example 1, except that the molar ratio of Ir to Ta in step S2.1 is 8:3 and the Ir content is slightly higher.

[0031] Comparative Example 1 This comparative example was processed using the same pretreatment and Ir-Ta coating preparation process as in Example 1 to obtain a single-layer anode without an outer mesh.

[0032] Comparative Example 2 It is basically the same as Example 1, except that 2-aminoterephthalic acid is not included in step S2.2.

[0033] Comparative Example 3 It is basically the same as Example 1, except that in step S2.2, the MOF is not heat-treated after growth and is used directly for assembly.

[0034] Comparative Example 4 It is basically the same as Example 1, except that in-situ electrochemical activation is not performed in step S3.

[0035] Performance testing: 1. Lifespan: The sample prepared by cutting a 2cm*2cm sample from the examples and comparative examples was used as the anode, and a titanium plate was used as the cathode. The electrolyte was a 20% (w / w) H2SO4 solution, and electrolysis was performed using a DC power supply with a current density of 5A / cm². -2 When the voltage increases by 5V from the initial voltage, the anode fails, and the cumulative electrolysis time is recorded. 2. Deep plating capability (TP value): Electroplating was performed on the anodes prepared in the examples and comparative examples. The electroplating solution temperature was set at 25°C, the current density at 4.0 A / dm², and the electroplating time at 45 min. The through-hole diameter of the sample test plate was 0.3 mm, and the thickness-to-diameter ratio was 10:1. The electroplating solution was an acidic copper plating solution, composed of CuSO4·5H2O 220 g / L, H2SO4 60 g / L, and Cl... -Add 60ppm of brightener SPS 10ppm and leveling agent PEG 300ppm; perform cross-sectional analysis on each electroplated copper sample, measuring at least 10 through holes. After electroplating, refer to the industry-standard "6-point method" test: cut the test board along the axis of the through hole, and take the average thickness of the copper plating layer on the hole wall at 6 points indicated by the same through hole cross-section (two points each at the top of the hole opening, the center of the hole, and the bottom of the hole opening, in mutually perpendicular directions). Then measure the surface copper plating thickness of the sample board. The TP value is calculated by comparing the average copper plating thickness at the 6 points on the hole wall with the average copper plating thickness on the sample surface. The results are shown in the table below:

[0036] Based on the above data, it can be seen that Example 1 performs best in all performance indicators. Therefore, the anode prepared by the present invention has excellent stability and lifespan, which can help improve the electroplating quality.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A double-layer titanium mesh anode for PCB electroplating, characterized in that, The double-layer titanium mesh anode includes a first titanium mesh layer and a second titanium mesh layer; The mesh size of the first titanium mesh layer is larger than that of the second titanium mesh layer, and the meshes of the first and second titanium mesh layers are staggered.

2. A method for preparing a double-layer titanium mesh anode for PCB electroplating as described in claim 1, characterized in that, The specific steps are as follows: S1. Titanium mesh pretreatment: The titanium mesh was subjected to alkaline washing and degreasing with 10wt% sodium hydroxide solution, ultrasonic-assisted acid etching and electrochemical activation treatment in sequence to obtain a pretreated titanium mesh. S2, MOF self-assembly: S2.1 Preparation of the first titanium mesh layer: Chloroiridic acid and tantalum pentachloride were added to n-butanol to prepare a precursor solution with a total metal ion concentration of 0.18~0.22mol / L. The solution was stirred to obtain a coating solution. The coating solution was uniformly coated on both sides of the titanium mesh, dried at 110~120℃ for 10min, and then placed in a muffle furnace for heat treatment in air atmosphere to obtain the first titanium mesh layer. S2.2, Preparation of the second titanium mesh layer: Cobalt dichloride hexahydrate was mixed with anhydrous ethanol to prepare a 5-6 mmol / L metal solution; 2-aminoterephthalic acid and terephthalic acid were mixed and added to N,N-dimethylformamide to prepare a 5-6 mmol / L organic ligand solution, and then an equal volume of anhydrous ethanol was added and mixed evenly to obtain mixture A. The pretreated titanium mesh is first immersed in the metal solution for 30-35 minutes, then rinsed with anhydrous ethanol for 30-40 seconds, then immersed in the mixture A for 30-35 minutes, then rinsed with anhydrous ethanol for 30-40 seconds; the above immersion and rinsing steps are repeated 20 times, and the second titanium mesh layer is obtained after heat treatment. S3, Double-layer anode assembly: The first titanium mesh layer and the second titanium mesh layer are fixedly connected, with a preset interval between the two layers and the mesh holes are staggered.

3. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S1, the ultrasonic-assisted acid etching process is as follows: The titanium mesh was immersed in a 1:1 mixture of 18wt% hydrochloric acid and saturated oxalic acid and subjected to ultrasonic treatment at 40-45kHz at 90℃ for 2 hours.

4. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S1, the electrochemical activation treatment is as follows: using an acid-etched titanium mesh as the working electrode, applying an anodic potential of 1.5V in a 10wt% oxalic acid solution, and performing constant potential polarization treatment for 30 min.

5. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S2.1, the specific process of the heat treatment is as follows: first, the temperature is raised to 400-415℃ at a heating rate of 3-5℃ / min and held for 10-15min, then the temperature is raised to 490-505℃ at the same rate and held for 30min, then the furnace is naturally cooled, and finally the final heat treatment is carried out at 500℃ for 1h.

6. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S2.1, the molar ratio of Ir to Ta in the precursor solution is (7~7.5):

3.

7. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S2.1, the loading of metallic Ir in the coating on the first titanium mesh layer is 20~25 g / m. 2 .

8. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S2.2, the molar ratio of 2-aminoterephthalic acid to terephthalic acid is 3:(7~8).

9. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S2.2, the heat treatment further includes, after repeating the operation every 5 times, placing the titanium mesh in a vacuum drying oven at 60°C for 2 hours, and after 20 times, placing the titanium mesh in a vacuum drying oven at 110~120°C for 12 hours, and then placing it in a tube furnace, heating it to 300~320°C at 2°C / min under argon protection and holding it there for 2 hours.

10. The method for preparing a double-layer titanium mesh anode for PCB electroplating according to claim 2, characterized in that, In step S3, the double-layer anode also undergoes in-situ activation, specifically by immersing the assembled anode in a 0.3 mol / L sulfuric acid solution at a rate of 30 mA / cm². 2 The current density was anodicly polarized for 45 min.

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