What is Black Oxide?

Black Oxide, Blackening, Oxiding, and Gun Bluing are all terms referring to the finish of Black Iron Oxide, on the surface of Ferrous Metals.

The Black Oxide finish is a hot chemical conversion coating resulting in the Black Oxide not being deposited on the surface of the substrate similar to zinc and nickel electroplating, but rather the Black Oxide coating is produced by the chemical reaction between the iron on the surface of the Ferrous Metal and the Oxidising solution. The solution contains Catalysts, Activators and Proprietary Additives, that, at just the right temperature, all take part in the Chemical Reaction resulting in the formation of Black Iron Oxide Magnetite (FE304) on the surface of the metal being coated. Black Oxide has a range of unique properties and benefits that can be applied to many industries.  The process has a number of steps to clean and prepare the metal before the conversion process and then other processes to provide the final finished product including a dewatering oil dip to provide corrosion resistance.

Black Oxide Coating will generally not require any special dimensional consideration - parts can be machined to finished size prior to coating. The Black Oxide converts the surface material into oxide, forming an ultra thin film less than 0.001mm. (one micron)  This results in dimensional stability allowing a Black Oxide coated nut and bolt to still fit together perfectly after the coating process.