Black Oxide Coating Thickness

A black oxide conversion coating is applied to ferrous alloys when oxidizing salts react with the iron to form magnetite fe 3 o 4 the black oxide of iron.

Black oxide coating thickness.

How black oxide coating works. One of its advantages over other coatings is. The point of the black oxide process is to create magnetite fe3o4 an alloy of iron and oxygen molecules on the surface of the metal. A discussion started in 1999 but continuing through 2018.

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 degrees f. Bluing is a passivation process in which steel is partially protected against rust and is named after the blue black appearance of the resulting protective finish true gun bluing is an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite fe 3 o 4 the black oxide of iron. Thickness of black oxide coating does not exceed 3 10 5 inch 0 75 µm half of which is added to the part dimension and the second half penetrates into the part depth. Services with cincinnati black oxide.

For decorative applications and can be used to decrease light reflection. I am outsourcing some components from taiwan and they have a difficult time maintaining a consistent plating thickness using zinc chromate on the steel parts. Dipping a metal part into a heated alkaline liquid for a specific period of time triggers the chemical process that forms magnetite on the part s surface. It is used to add mild corrosion resistance for appearance and to minimize light reflection.

Black oxide coating thickness. To achieve maximal corrosion resistance the black oxide must be impregnated with oil or wax. For moving parts which cannot tolerate the dimensional change of a more corrosion resistant finish. Mostly a decorative coating.

Only very limited corrosion protection under mild corrosion conditions. The reaction between the iron of the ferrous alloy and the hot oxide bath produces a magnitite fe3 o4 on the actual surface of the part. Though standard black oxide is set up for steel it can be done on other substrates including stainless steel copper and brass among others. Black oxide coating mil c 13924 a uniform black coating for ferrous metals.

I would like to consider using black oxide but need to know more about the capabilities. Black oxide coating does not peel from the surface. Strong adhesion between the coating and the substrate. Black oxide penetrates the steel 5 10 thousandths and adds to the part thickness by only 5 10 thousandths providing a hardness of 5 on the mohes scale.