素材小特集ＩＩＩ ： 素材製造プロセシング 純鉄およびステンレス鋼のプラズマ窒化

Abstract

Lately, it is becoming clear that plasma nitriding method has several differencial features comparing with ion nitriding. In this study, plasma nitriding of pure iron and SUS304 steel was carried out using r.f. nitrogen glow discharge. There were significant differences between pure iron and SUS304 steel in properties and growth mechanism of the nitrided layer with the temperature increase. In the plasma nitriding of pure iron, the nitriding rate was much higher than that in the ion nitriding processes for pure iron reported so far. The nitriding rate of SUS304 steel decreased rapidly as the nitriding time proceeded.The nitriding of pure iron and SUS304 steel using N2-H2 gas in r.f. plasma was impossible owing to the effect that activated hydrogen checked the growth of the nitrided layer.