The effect of nitrogen on the stability of the passive film on a Zeron 100super duplex stainless steel

The passivity of a super duplex stainless steel is addressed. It has been s hown previously that this steel etches preferentially in the ferrite phase in a chloride environment.(1) The relative stability of the austenite phase compared to the ferrite phase is partially related to the electrochemical stability of the passive film. The chemical distribution of the major passi vating elements in the film does not vary significantly on the two phases. However, the content of nitrogen in the film is substantially different bet ween the phases. The nitrogen content was enriched to about 4 atom % in the film on the austenite phase, while it was absent in the film on the ferrit e phase. This study was performed by in-depth chemical profile analyses usi ng Auger electron spectroscopy. (C) 1999 The Electrochemical Society. S1099 -0062(98)07-060-6. All rights reserved.