The black oxide process is a chemical conversion coating. This means that the black oxide is not deposited on the surface of the metal like nickel or zinc electroplating. The black oxide coating is made by a reaction between the iron on the surface of the ferrous metal and the oxidizing salts present in the black oxide solution. Because of this, most nonferrous metals cannot be blackened. Oil treatments are often used after the blackening process to increase corrosion resistance and to produce a deeper black color. Blackening cannot be done over top of aluminum, zinc, chrome, or other plating finishes. It can done on bronze, brass, and copper plating as well as steel.
Black oxide is one of the thinnest finishes, so if tight dimensions are a priority for you this coating may be a good solution. Black oxide is not completely corrosion resistant, but it has the ability to absorb a layer of wax or oil to increase the corrosion resistance.
Black oxide parts lose a maximum of 1% conductivity, making it a good fit for coating electrical components. We work closely with suppliers who know the blackening process like they know the back of their own hands. Black oxide can be applied selectively to only a portion of the product, but it is not an exact procedure. Areas that you don’t want to be blackened (usually for dimensional restriction reasons) can be masked during the blackening process. Let us know if you’d like your parts blackened before we ship them back to you.
Blackening is often done for aesthetic reasons. Black oxide greatly reduces light reflection and is suitable for a variety of applications. Black oxide is also a better surface for paint and primers than bare metal. It can help to reduce chipping and flaking after the paint is dried.
Unlike painted products, welding black oxide does not cause fumes. Blackened products can still be bent, twisted and formed which is not an option for many other coatings. Contact us today, we are ISO 9001:2008 certified.