Abstract
Mg is the lightest metal in practical use, and its specific gravity is 1/4 that of iron and 2/3 that of aluminum. It has higher specific strength and rigidity. However, since Mg has the lowest standard electrode potential among practical metals and is chemically active, it is a material that is easily corroded. Therefore, it is generally said that the Mg alloy is subjected to surface treatment in order to improve the corrosion resistance. The surface modification and anticorrosive surface treatment of Mg are anodizing treatment, chemical conversion treatment, and plating treatment. However, these technologies have problems such as cost and durability of coatings that improve corrosion resistance, leaving room for improvement. In this study, we used functional cavitation (MFC) which has the characteristics of both water jet peening (WJP) and ultrasonic cavitation (UC). By adding phosphoric acid there, mechanochemical properties (MC) were added to each process to form a phosphoric acid film on the surface of the Mg alloy. Furthermore, as a result of evaluating the film characteristics, it was confirmed that a film containing P and O was formed on the surface of the Mg alloy, and that the corrosion resistance was improved by MC-MFC.
