Process Flow of Titanium Anode Coating

The process flow of titanium anode coating refers to the procedure of applying a functional coating onto the titanium substrate through specific methods, which enhances the performance and service life of the titanium anode.

During the surface pretreatment of the titanium substrate, mechanical grinding is first performed. Sandpaper with a grit size of 200–400 is used to control the surface roughness of the titanium substrate to Ra 3.2–6.3 µm, thereby increasing the adhesion between the coating and the substrate.

In the preparation of the coating solution, the corresponding metal salts, such as ruthenium salts, iridium salts, etc., are precisely weighed according to the required coating composition. These are then formulated into a solution with a concentration of 0.01–0.5 mol/L based on the stoichiometric ratio. For the coating application, the brushing method can be used, where a wool brush is dipped into the coating solution and evenly brushed onto the titanium substrate surface. The thickness of each coating application should be controlled within 10–20 µm. During the drying stage, the coated titanium anode is placed in an oven and dried at 80–120°C for 10–30 minutes to allow full evaporation of the solvent in the coating. In the thermal decomposition treatment, the dried titanium anode is placed in a high-temperature furnace and heated to 400–600°C at a heating rate of 5–10°C/min, maintaining this temperature for 1–2 hours to induce thermal decomposition reactions in the coating components.

During the multiple coating process, the steps of coating application, drying, and thermal decomposition are generally repeated 3–5 times to achieve a coating of sufficient thickness and good performance. For coating quality inspection, a metallographic microscope is used to observe the microstructure of the coating, which should be uniform and dense with a porosity of less than 5%. For adhesion testing of the coating, a scratch test can be performed by making a grid pattern on the coating surface, with the requirement that the coating detachment area should be less than 10%. During the coating application process, the ambient humidity should be controlled between 40% and 60%, as excessively high humidity can affect the drying and quality of the coating.

The solvents used are typically organic solvents, such as ethanol or isopropanol, with a purity of no less than 99% to ensure the stability of the coating solution.