... oxygen precipitation by oxidation, the formation of the anhydrous 12O3 membrane: 4A1 + 3O2 = 2A12O3 + 3351J It should be ... According to the nature of the film are: ordinary film, hard-plasma membrane (thick film), ceramic membrane, light-modified layer, the semiconductor ... be better after the corrosion resistance; colorless, transparent film, adsorption ability to easily coloring; deal with the lower ...