Corrosion Resistance of Plasma Nitrided AISI 316L Stainless Steel in Low Temperatures

摘要

Plasma nitrided stainless steel contain ε-Fe_(2-3) N e γ'-Fe_4N at the surface (white layer) and chromium nitrides. Chromium nitrides decrease the corrosion resistance of a stainless steel. Under controlled conditions the plasma nitriding at low temperature results in a formation of called "S-phase", that improves improves the corrosion properties. This work is a corrosion study at an AISI 316L austenitic stainless steel (SS 316L) after different eighteen plasma nitriding conditions. The sample nitrided at 375°C for four hours in gaseous mixture of 5%N_2-95%H_2 gave the best corrosion resistance. The corrosion resistance was associated with the microstructure obtained after plasma nitriding for this conditions.