The anodizing coloring process
Degreasing (strong alkaline degreaser) → Water washing → Initial pickling (hydrofluoric acid aqueous solution) → Water washing → Secondary pickling (hydrofluoric acid + hydrogen peroxide aqueous solution) → Water washing → anodizing (Constant voltage electrolysis in phosphoric acid solution) → Water washing → Sealing → Drying.
3. Secondary pickling
For constant voltage treatment, the aluminum plate was utilized as the cathode and the prepared titanium plate as the anode, with phosphoric acid as the electrolyte at 1% weight concentration. As the voltage increases, the oxide deposit on the titanium surface thickens and changes color.