Beneficial Effect of Impurity Sulfur on High-Temperature Steam Oxidation of High Chromium Ferritic Steels
The effect of S in steels on high-temperature steam oxidation resistance was investigated with respect to the content and the state in high Cr ferritic steels. The beneficial sulfur effect on high-temperature steam oxidation resistance was verified in high Cr ferritic steels. It was considered that Cr was enriched in the vicinity of the segregated S on the specimen surface because of a strong affinity between Cr and S atoms, resulting in the easy formation of the passive Cr2O3 oxide layer on the surface even after the steam oxidation test for a short time. It was found that the precipitated S operated more effectively to the improvement of the steam oxidation resistance compared to the solid-solution state of S in the steels. Furthermore, the sulfur effect on the high temperature steam oxidation resistance was related strongly to the amount of dissolution hydrogen in the high Cr ferritic steels.
Shigeji Taniguchi, Toshio Maruyama, Masayuki Yoshiba, Nobuo Otsuka and Yuuzou Kawahara
Y. Murata et al., "Beneficial Effect of Impurity Sulfur on High-Temperature Steam Oxidation of High Chromium Ferritic Steels", Materials Science Forum, Vols. 522-523, pp. 147-154, 2006