A comparative study of ion beam nitriding of single-crystalline and polycrystalline 316L austenitic stainless steel

Nitriding of an austenitic stainless steel (ASS) at moderate temperature (400 degrees C) increases significantly its hardness without loss of corrosion resistance. This study presents the first comparison between single crystalline ([001], [011] and [013] orientations) and polycrystalline 316L ASS ion beam nitriding. The current density, ion energy and temperature were 0.5 mA center dot cm(2), 1.2 keV and 400 degrees C, respectively. The nitrogen distribution profiles were measured by nuclear reaction analysis (NRA). A notable difference of nitrogen penetration between polycrystalline and single-crystalline samples is observed, depending on the orientation of the single crystals. The nitrogen penetration is higher for [100] and [013] oriented single crystals. X-ray diffraction (XRD) reveals the presence of the gamma(Nu) phase in both types of samples. Moreover, it shows that the nitrided layer in single crystals exhibits disorientations in relation to the matrix. (c) 2004 Elsevier B.V. All rights reserved.