Chemical alumina aluminum plate is weakly alkaline or weakly acidic solution, part of the base metal reacts to the surface of a natural oxide film thickening or some other process to produce passivation film, there is commonly used chemical chromic oxide film and phosphoric acid membrane, which is thin and good adsorption, can be colored and sealing treatment.
Thin oxide film having a large number of pores, can adsorb various lubricants, suitable for the manufacture of engine cylinder or other wear-resistant parts; microporous membrane adsorption ability can be colored in a variety of beautiful and bright colors. Non-ferrous metals or alloys thereof (e.g., aluminum, magnesium and their alloys, etc.) can be subjected to an anodic oxidation treatment.
Anodic aluminum oxide, aluminum oxide thin layer formed on the surface to a thickness of 5 to 20 microns, hard anodic oxide film can reach 60 to 200 microns. Aluminum anodizing, improved hardness and wear resistance, up to 250 to 500 kg / mm, good heat resistance, hard anodic oxide film up to the melting point of 2320K, excellent insulation resistance, breakdown voltage up to 2000V, enhanced corrosion resistance by salt spray at ω = 0.03NaCl thousands of hours without corrosion.
Anodized aluminum plate is placed in the appropriate electrolyte aluminum (such as sulfuric acid, chromic acid, oxalic acid, etc.) as an anode, under certain conditions and the role of the applied current, electrolysis.
