Coupling Effect of Precipitates and Hydrogen on Pitting Corrosion of Stainless Steel

This study investigated the coupling effect of hydrogen and precipitates on the initiation of pitting using HR3C stainless steel with large NbCrN precipitates as the study material. Stainless steel exhibited good resistance to pitting when not subject to hydrogen charging. Hydrogen charging significantly reduced the corrosion resistance and stability of the passive film. Results obtained using the hydrogen microprint technique revealed that hydrogen was enriched within NbCrN precipitates and along the precipitate/substrate interface. Through immersion experiments, we discovered that pits preferentially initiated at the precipitate/substrate interface because they had weaker corrosion resistance than the precipitates.