抄録
It is difficult to nitride stainless steels with out treatments for their surfaces because they have strongly passivated surface films. An ion-nitriding method seemed to be effective for nitriding these steels, as the passivated films could be removed by ion's spattering. Stainless steels were ion-nitrided in gas mixtures of nitrogen and hydrogen in the present study. Highly hardened surface layers were obtained in short nitriding times of 1-5h. The layers had decreasing depth in order of the stainless steels of ferritic, ferrite-austenite mixing, and austenitic structures. The depth of the layers decreased with increasing chromium content in the steels. It is suggested that the precipitation of chromium nitride caused the high surface hardening of the stainless steels, because the presence of the nitride was confirmed by X-ray diffraction.
