Description / Abstract: This specification covers black oxide finishes applied over iron and steel parts and 300 series stainless steel parts for decorative or identification purposes. It offers little wear resistance, and no corrosion resistance unless accompanied by additional supplemental topcoat or oil.

Material Description. The finish is a magnetite type black oxide conversion layer produced by immersion of the part in a hot alkaline salt solution or mixed salt fusion bath.

Applicability. Black oxide is not generally used for 400 series stainless steel and offers little protection when applied over 200 series stainless steel parts.

Remarks. Protective oils and waxes may be applied over black oxide to improve resistance to corrosion, in which case the improvement is proportionally equal to the quality of the oil/wax. Oil and/or wax coating shall be specified as a suffix to this specification in the drawing as required.