Anodic oxidation: Anodic oxidation is actually the electrolysis of water. When the electrolyte is electrified, hydrolysis occurs under the action of electric current. Hydrogen is released from the cathode, and some of the newly formed (atomic) oxygen reacts with aluminium (anode) to form alumina film on the anode. Grade of oxide film: AA10, AA15, AA20, AA25, commonly used is AA15; the surface form is matte, sandy (hemp) surface, smooth surface;
Advantages and disadvantages of anodic oxidation: anodic oxidation process, uniform film thickness, high film hardness, good wear resistance, solid, uniform and scattering coloring electrodeposition; but the color of oxidation coloring is monotonous. Because the production process of oxidation is to clean, oxidize, colour and seal the aluminium material in the oxidation tank liquid. The bath liquid is made up of a variety of chemical elements. Every batch of aluminium material is oxidized, the chemical composition in the bath is changing. Therefore, the bath liquid is variable. The aluminium material colored by oxidation always has color difference. It is not obvious to the naked eye when placed alone. If put together in large areas, the color difference is very obvious.