Understanding Corrosion Behavior of Magnesium Surface by x-Ray Irradiation for Improved Surface Design and Applications

An advanced surface modification processing design has been developed to improve the corrosion resistance of magnesium (Mg) samples via x-ray irradiation in humid air. OH· radicals generated by water ionization during x-ray irradiation reacted with natural oxide films mainly consisting of Mg(OH)2, which resulted in the formation of an approximately 50-nm-thick magnesium oxide (MgO) dense surface film as a protection layer against corrosion. After x-ray irradiation for 24 h, pure Mg and its alloy (AZ91D) specimens underwent the saltwater immersion test and exhibited a remarkable reduction in corrosion rate (80-85%). They were also compared to as-received samples after polishing treatment. This surface modification process is environmentally friendly because it does not release any hazardous materials because of the high recycling ability.