Corrosion behaviors of four stainless steels with similar chromium content in supercritical carbon dioxide environment at 650 ℃

摘要

The corrosion behavior of four stainless steels (SSs) with similar chromium content was investigated in supercritical carbon dioxide environment. Overall, weight gain was the smallest for 630 SS which formed thin and continuous Cr-rich oxide layer. Due to large Mn3O4 nodules, weight gain was larger for 430 SS. For 347H and 316LN SSs, thick duplex oxide layers were formed following the extensive oxide spallation, resulting in much greater weight gains than 430 and 630 SSs. The oxide spallation was explained by the formation of Nb-rich layer or amorphous matters at the matrix/oxide interface as well as the matrix structure.