ABSTRACT
Significant improvements in the wear resistance of austenitic stainless steels can be achieved by plasma nitriding. Unfortunately, especially at high temperatures, this treatment tends to affect the corrosion performance of stainless steels adversely, as a result of either CrN precipitation, thereby removing chromium from solid solution, or the formation of iron nitrides on the surface. Recently, it has been demonstrated that it is possible to improve the wear resistance of stainless steels without compromising their corrosion performance by using plasma immersion ion implantation (PI3), which is essentially a hybrid technique combining plasma nitriding and conventional nitrogen implantation. However the reason for improved corrosion resistance had not been unequivocally determined. Based on cross-sectional transmission electron microscopy, it is shown that PI3 is capable of producing amorphous layers which are responsible for improved resistance.
