RF PLASMA NITRIDING OF PURE IRON AND STAINLESS-STEEL

In r.f. inductively coupled plasma (r.f.-ICP) nitriding, the nitriding of iron is prevented by the addition of hydrogen. However, in this st udy, the r.f.-ICP nitriding of iron surface was achieved by the applic ation of negative bias voltage even in the presence of hydrogen. It se ems that the effect of bias voltage overcomes the additive effect of h ydrogen. Furthermore, the r.f.-ICP nitriding of SUS304 in the presence of hydrogen was investigated. At 550 degrees C, the nitriding was sup pressed by the addition of hydrogen, as well as the nitriding of iron. However, the nitriding was promoted by the addition of hydrogen at 35 0 degrees C, and a hard nitrided layer was obtained. On the contrary, SUS304 was not nitrided without hydrogen at 350 degrees C. (C) 1998 El sevier Science S.A. All rights reserved.