The chemical aluminum oxidation process of aluminum and aluminum alloys in Suzhou oxidation plant can be divided into two categories: alkaline aluminum oxidation method and acid aluminum oxidation method according to the properties of its solution. According to the properties of the film, it can be divided into aluminum oxide film, phosphate film, chromate film and chromic acid phosphate film.

Aluminum in Suzhou oxidation plant is a relatively active metal with a standard potential of -1.66v. It can naturally form an aluminum oxide film with a thickness of about 0.01 ~ 0.1 microns in the air. This aluminum oxide film is amorphous, thin and porous, and has poor corrosion resistance. However, if aluminum and its alloys are placed in an appropriate electrolyte, aluminum products are used as anode, and aluminum oxide film is formed on its surface under the action of external current, this method is called anodic aluminum oxidation. By selecting different types and concentrations of electrolytes and controlling the process conditions of aluminum oxidation, anodic aluminum oxide films with different properties and thickness of about tens to hundreds of microns can be obtained, and their corrosion resistance, wear resistance and decoration have been significantly improved.

Sulfuric acid anodic aluminum oxidation in Suzhou oxidation plant: aluminum and its alloys are anodized with DC and AC in dilute sulfuric acid electrolyte to obtain a colorless transparent aluminum oxide film with a thickness of 5 ~ 20 microns and good adsorption. Sulfuric acid anodized aluminum has the advantages of simple process, stable solution, convenient operation, wide allowable impurity content range, less power consumption and low cost. It is almost suitable for the processing of aluminum and various aluminum alloys, so it has been widely used in China.