FORMATION BEHAVIOR AND CORROSION CHARACTERISTICS OF ANODIC FILMS ON MG-AL ALLOYS IN NAOH SOLUTIONS

摘要

The formation behavior and corrosion characteristics of anodic oxide films on pure Mg and Mg-Al alloys were investigated focusing on the effects of anodizing potential, Al content, temperature and NaOH concentration. Pure Mg and Mg-Al alloys were anodized for 10 min at 3, 10, 40, and 80 V in NaOH solutions. Mg(OH)_2 was generated by an active dissolution reaction at the surface of the specimen and the product was affected by temperature while MgO generation increased with NaOH concentration. Moreover, the current density after anodizing for 10 min at a constant potential decreased with increasing Al content in Mg-Al alloys.