Two different nitriding surface treatments of austenitic stainless ste
el have been studied: gaseous nitriding in a NH3-H-2 mixture performed
at temperatures between 700 and 900 degrees C and nitrogen ion implan
tation with different dose rates between 5 x 10(16) to 1.5 x 10(17) N-
2(+) ions cm(-2) and different current densities between 1 to 5 mu A c
m(-2). The microstructure of the coating was studied by X-ray diffract
ion and Mossbauer spectroscopy. The discussion emphasizes the role of
thermodynamical equilibrium conditions at high temperatures and of the
process parameters at low temperatures on the phases which constitute
the layer.