Anodize

This is an electrolytic passivation process used to increase the thickness and density of the natural oxide layer on the surface of metal parts. On certain metals, such as those used on electric guitars and basses, anodizing increases both corrosion and wear resistance, as well as providing better adhesion for paint primers and glues than bare metal. Fender’s gold-tinted aluminum pickguards of the 1950s have typically been described as “anodized,” however the correct term for this specific finish is “anodined.”