2. Coloring: various colors are formed on the oxide film to meet certain use requirements, such as black for optical instrument parts and golden yellow for commemorative medals.
3. Conductive oxidation: used in situations where both protection and conductivity are needed.
4. Chemical oxidation: the oxide film is thin, porous, soft and good in adsorption.
5. Electrochemical oxidation: The chemical oxidation treatment equipment for aluminum and aluminum alloy is simple, easy to operate, with high production efficiency, no power consumption, and wide application range, which is not limited by the size and shape of parts.
6. Spraying: used for external protection and decoration of equipment, usually based on oxidation. Before painting, aluminum parts should be pretreated to make the coating firmly combined with the workpiece. Generally, there are three methods: phosphating, chromizing and chemical oxidation.
7. Passivation: A method of changing the metal surface to a state that is not easy to be oxidized, thereby delaying the corrosion rate of metal.