Profile: Dekalb Metal Finishing Inc. specializes in autophoretic, zinc and zinc alloy plating. We offer zinc alkaline, zinc iron, chromate conversion, passivation, zinc-nickel, E-coat, shipping and delivery information. We are certified to ISO/TS 16949 standards. Passivation is the spontaneous formation of a hard non-reactive surface film that inhibits further corrosion. This layer is usually an oxide or nitride that is a few atoms thick. Passivation begins by treating metal with a mild oxidant in order to remove surface iron or iron compounds. This action forms a protective “passive” film on the surface of the metal.