Corrosion behavior of HR3C austenitic stainless steel in supercritical water near the critical point

The corrosion behavior of HR3C stainless steel was investigated in supercritical water near the critical point. Results show that HR3C steel displays an unusual weight change behavior. Traditional weight gain behavior is detected in the initial corrosion stage because of the formation of spinel oxide scale and crater-like Nb-rich oxides. The detaching of crater-like Nb-rich oxides results in weight loss behavior during the middle corrosion stage. After 1200 h exposure, the diffusion-controlled growth of outer Fe₂O₃ particles leads to the reoccurring of weight gain behavior. The formation of crater-like Nb-rich oxides is closely associated with the primary Z-phase precipitates.