Cathodic cage plasma nitriding (CCPN) of austenitic stainless steel (AISI 316): Influence of the different ratios of the (N2/H2) on the nitrided layers properties

In this study, we assess how the ratio (N-2/H-2) - working atmosphere gas mixture - influences the properties of the layers produced on austenitic stainless steel surface by Cathodic Cage Plasma Nitriding (CCPN). The nitriding atmospheres contained nitrogen and hydrogen in three proportions: 20% N-2 + 80% H-2, 50% N-2 + 50%H-2, and 80% N-2 + 20% H-2 delivered at a flow rate of 20 sccm. The effect of 100% N-2 was also examined. The morphology, microstructure and electrochemical properties of the layer produced were studied. The samples characteristics were determined by optical microscopy, x-ray diffraction, microhardness test and electrochemical potential curves. (C) 2012 Elsevier Ltd. All rights reserved.