Anodizing of magnesium alloys
Anodizing can be better than the chemical conversion of wear-resistant, corrosion-resistant paint base coat, and has good adhesion, electrical insulation and thermal shock properties, is one of the most common surface treatment technology of magnesium alloy.
Traditional magnesium alloys anodizing electrolyte containing chromium, fluorine, phosphorus and other elements, not only pollute the environment, and harm to human health. In recent years by the research and development of environment-friendly technology of oxide film on corrosion-resistant properties than classical technique Dow17 and HAE has greatly improved. Excellent resistance to corrosion from the anode oxidation of Al, Si and other elements evenly distributed on the surface, so that the oxide film formed good compactness and completeness.
The pores of the oxide film is generally considered major factors affecting the corrosion resistance of magnesium alloys. Study finds through anode oxidation addition of some silica-alumina Sol solution components, can improve to a certain extent the oxide film thickness, density and reduce the porosity. And Sol composition film fast and slow growth stage, but has little effect on x-ray diffraction of the film structure.
But the larger brittle, porous Anodic oxide film, difficult to obtain even in complex workpieces of oxide film.