Oxidation
Oxidation:chemical reaction of oxygen and other elements occurring substances, called oxidation, is also an important chemical unit processes, but also refers to a substance loses electrons (oxidation number increases) in the process.
Natural aluminum surface is soft and thin, poor corrosion resistance, it can not be an effective protective layer but not suitable for coloring. Artificial system oxide film is mainly used chemical oxidation and anodic oxidation. Chemical oxidation of aluminum products is weak alkaline or weak acid solution, part of the base metal reacts to the surface of the natural oxide film thickening process or produce some other passivation film, commonly used chemical oxide film has a chromate film and phosphoric acid membrane, which is thin and good adsorption, can be colored and sealing treatment, table-3 describes the chemical oxidation process aluminum products. Compared with the chemical oxide anodic oxide film, the film is much thinner, corrosion resistance and hardness is relatively low, and easy colored, colored light resistance is poor, so the colored aluminum and anodized color presentation only.