Abstract: Disclosed is a method for forming a conversion coating on the outer surface of magnesium or a magnesium alloy by surface treatment with acidic and alkaline solutions. The method is carried out in an environmentally friendly manner to improve the corrosion resistance of the magnesium or magnesium alloy. The method minimizes the damage to the appearance of the magnesium or magnesium even after surface treatment and maximizes the attractive appearance of the magnesium or magnesium alloy.

Abstract: Disclosed herein is a method for the surface treatment of magnesium or a magnesium alloy by anodization to form an anodized oxide coating on the magnesium or magnesium alloy. The method comprises: removing impurities and an oxide layer present on the surface of magnesium or a magnesium alloy using a strongly alkaline aqueous solution (pretreatment); and immersing the pretreated magnesium or magnesium alloy in an alkaline electrolyte and applying a direct current having a current density of 3 A/dm2 or less to the electrolyte to form a magnesium oxide coating (microarc plasma anodization).