Phase and microstructural study of surface layers produced by plasma immersion ion implantation of stainless steel X6CrNiTi1810

A complex study of austenitic stainless steel X6CrNiTi1810 modified by, nitrogen plasma immersion ion implantation (PI(3)) at 300 and 400 degrees C is presented. To obtain detailed information on the structure and phase compositions, conversion electron Mossbauer spectroscopy: XRD, TEM and Rutherford backscattering spectroscopy ale applied. Depending on the treatment temperature a mixture of several phases is observed by Mossbauer phase analysis and confirmed by TEM. The dominant component in specimens treated at 300 degrees C is a paramagnetic oversaturated austenitic phase. A higher implantation temperature (400 degrees C) evokes more pronounced diffusion of nitrogen into the specimen volume?, causing a decrease of nitrogen concentration but an increase of stress in the surface layer. This influences the defect density, and results in a change of the expanded austenitic phase. Nitride formation is also different depending on the temperature. Furthermore,lore, a texturing of the grains is observed after the PI(3) treatment at both temperatures. (C) 1999 IoM Communications Ltd.