High purity 316L type stainless steels with various levels of nitrogen were prepared with and without the addition of manganese. Both crevice corrosion potential and pitting potential showed nobler values with increasing amount of nitrogen but less pronouncedly in Mn containing stainless steels. The enhanced resistance to corrosion of N-bearing steels is due to the improvement in repassivation kinetics rather than the improvement in film properties, which has been proved by the measurement of film recovery after the removal of passive film. By chemical analysis it is proven that nitrogen in steel is transformed into ammoniacal state even in anodic dissolution of metals reduction occurs. It is presumed that interstitial nitrogen acts to some extent as a passivator.
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