Abstract
In order to make a further understanding of plasma ion nitriding process, we observed the relationship between the cathode fall voltage of D.C. glow plasma and the nitriding situation of metal surface. We used a stainless steel (SUS304) as a specimen, because it had the strong oxide film on the surface.
If we nitrided SUS304 which was placed as a cathode then we could obtain the nitride layer without oxide on the surface of SUS304 under the voltage condition of 600-800 volts, which we selected as an optimum voltage range for nitriding. This voltage range corresponded to the conditions for absolutely sputtering the oxide surface film on metal and prevent oxygen to diffuse into bulk.
