Possible mechanisms for the improvement by vanadium of the pitting corrosion resistance of 18% chromium ferritic stainless steel

Vanadium additions increase the pitting potential of 18% chromium ferritic stainless steel. Artificial-pit measurements showed that this is not related to any change in the dissolution kinetics in the pit anolyte, in contrast with the effect of molybdenum which lowers the dissolution rate strongly. A decrease in the nucleation rate of metastably growing pits is found for vanadium-alloyed steels, but the effect is smaller than for molybdenum alloying. The salt film in artificial pits in vanadium-alloyed steels was found to dissolve more slowly than for the molybdenum-alloyed steels; the slower dissolution is expected to contribute to the pitting resistance of the vanadium-alloyed steels. (C) 2002 Published by Elsevier Science Ltd.