Glancing and normal incidences X-ray diffraction of plasma ion nitrided austenitic stainless AISI 304 steel

Abstract

Samples of AISI 304 austenitic stainless steel were treated by a modified ion nitriding process. The process consists of a nitriding cycle at high pressure and temperature, followed by a cycle at low pressure under the high temperature attained in the first cycle. These treatments were performed using two gas mixture of (N 2/H 2):(50/50) and (80/20). Results of glancing and normal X-ray diffraction showed clearly the standard austenite ã-phase, the expanded austenite ã N-phase, induced by the presence of nitrogen atoms in solid solution and also the martensite á-phase. Microhardness Vickers tests, with 25gf load, showed surface hardness 1.8 to 2.7 times higher than the standard AISI 304 value. These results were attained within treatment times ranging from 70 to 150 min. These times are very short, compared with more classical nitriding processes.

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