Vanadium nitride is formed during the nitriding of steel and increases wear resistance. Usually steels are beneficially treated with plasma nitriding. Investigation into gas nitriding began independently in both Germany and America. The three main methods used are&colon; "gas nitriding", "salt bath nitriding", and "plasma nitriding". No quenching is done after nitriding. "Plasox" plasma-based nitriding surface treatment. After applying the nitriding process, a black Parkerized decorative surface finish is applied. Following this the ion nitriding process was invented in the early 1980s. In the plasma nitriding processes, nitrogen gas (N) is usually the nitrogen carrying gas. Despite the naming the process is a modified form of nitriding and not carburizing. Nitriding heats the steel part to in an atmosphere of ammonia gas and dissociated ammonia. Minimal amounts of material should be removed post nitriding to preserve the surface hardness.