Black Oxide: is typically used to establish a protective coating over steel and cast iron that is corrosion resistant, and has a uniform black finish or bronze color in the case of cast iron. The conversion is created by a chemical reaction with the oxidizers and the metal, as oxidizing salts react with iron magnetite to create a fusion resulting in a complete integration with the metal it protects. The result adds less than 5-10 millionths of an inch to the dimension of the piece. Black Oxide is used widely on all types of fasteners, nuts, bolts, washers, hinges, machining tools, stampings, and firearms.  

Dimensional Stability- Black oxides success is due to its’ ability to give cosmetic appeal without dimensional change in the size of the piece nor is there any reduction in the hardness of heat treated parts.

Durability- Hot black oxide finish will not chip, craze, peel, or rub off as is in the case of the cold black oxide process. The only way to remove the finish is by mechanical or chemical methods.

Economical- Protection, appearance, and performance qualities can not be achieved with other finishes for the same low cost as the Black Oxide process. The lustrous black finish adds visual appeal and a quality image at a very low cost. Hardened parts, 40 Rockwell and above will have a glossier finish while softer parts tend to have a matte finish.

Protection- Oxidized surfaces have an excellent ability to absorb oils, waxes, and lacquers.

Adhesion- Black Oxide increases adhesion qualities of treated surfaces making it highly effective primer for paints and other finishes.