by Rick Delawder & Mike Delawder, SWD Inc.
Black oxide is unlike any other finish. No other process produces the same finish and combination of properties. It can be used on steel, stainless steel, brass and copper to produce a rich, black finish.
What is It?
Black oxide is a conversion coating formed by a chemical reaction produced when parts are immersed in the alkaline aqueous salt solution operated at approximately 285°F. The reaction between the iron of the ferrous alloy and the hot oxide bath produces a magnetite (Fe3O4) on the actual surface of the part.