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, nit rogen plasma immersion ion implantation (PI3) at 300 and 400 degrees C is p resented. To obtain detailed information on the structure and phase composi tions, conversion electron Mossbauer spectroscopy: XRD, TEM and Rutherford backscattering spectroscopy ale applied. Depending on the treatment tempera ture a mixture of several phases is observed by Mossbauer phase analysis an d confirmed by TEM. The dominant component in specimens treated at 300 degr ees C is a paramagnetic oversaturated austenitic phase. A higher implantati on temperature (400 degrees C) evokes more pronounced diffusion of nitrogen into the specimen volume?, causing a decrease of nitrogen concentration bu t an increase of stress in the surface layer. This influences the defect de nsity, and results in a change of the expanded austenitic phase. Nitride fo rmation is also different depending on the temperature. Furthermore,lore, a texturing of the grains is observed after the PI3 treatment at both temper atures. (C) 1999 IoM Communications Ltd.