A series of low pressure plasma are source ion nitriding experiments has be
en conducted on AISI 304 stainless steel at temperatures ranging from 350 t
o 460 degrees C in an N-2-H-2 gas mixture. The structure and composition of
the plasma nitrided layers were studied by optical metallography, X-ray di
ffraction (XRD) and Auger electron spectroscopy (AES). The thickness of the
nitrided layer depends on the plasma nitriding temperature. After 2h of ni
triding at 420 degrees C, a 12 mu m nitrogen supersaturated austenite nitri
ded layer with nitrogen content up to 45 at% on the surface was formed. The
hardness values of the nitrided layer measured are in the range of 4.6 GPa
for the sample nitrided at 350 degrees C to 12.0 GPa for the sample nitrid
ed at about 420 degrees C. (C) 2000 Elsevier Science S.A. All rights reserv
ed.