AL passivation refers to the process of forming a thin film of alumina on the surface of aluminum, which can be expressed by the following equation:
2Al 3H2O 3O2 → Al2O3 3H2O
This equation shows how aluminum reacts with water and oxygen to form alumina. During the passivation process, a thin film of alumina on the surface of the aluminum provides protection against further oxidation and corrosion. This passivation film has good corrosion resistance and wear resistance, so that aluminum has a longer service life and a wider range of applications.
The passivation reaction equation of aluminum is 2Al 6HNO3=Al2O3 6NO2 3H2O, 2Al 3H2SO4=Al2O3 3SO2 3H2O, and the essence of passivation is to generate a dense oxide film.