ELECTROCHEMICAL AND SURFACE STUDIES OF THE AGING OF PASSIVE LAYERS GROWN ON STAINLESS-STEEL IN NEUTRAL CHLORIDE SOLUTION

The pitting corrosion of unimplanted and Ne, N and Mo-implanted 304 st ainless steel specimens was studied in a neutral chloride 0.02 M envir onment. The effect of ageing of the oxide layers during immersion in c hloride solution was investigated with respect to pitting corrosion re sistance. Pitting potential measurements were performed and showed lar ge differences on both the nature of implanted ion and the ageing trea tment: implanted samples exhibited lower pitting potentials than the b are alloy but an improved behaviour was observed after ageing. Surface analyses (XPS and SIMS) were used to detect compositional changes ind uced by ageing and to explain the experimental results.