Magnesium hydroxide/magnesium phosphate compounds composite coating for corrosion protection of magnesium alloy by a combination process of chemical conversion and steam curing

Abstract Anticorrosive composite films composed of amorphous or crystalline magnesium phosphate compounds and crystalline magnesium hydroxide were successfully prepared on magnesium alloy by a combination process of chemical conversion and steam-curing for the first time. The films had film thicknesses of ca. 30 μm and were composed of outer and inner layers. The corrosion resistances of the films coated magnesium alloy were investigated by electrochemical and gravimetric measurements. The films showed a much higher corrosive resistance than the uncoated one in corrosion tests.