SULFIDATION BEHAVIOR OF A FERRITIC COMMERCIAL ALLOY IN DIFFERENT SULFIDIZING ENVIRONMENTS AT HIGH-TEMPERATURE

The sulfidizing behavior of Fe-22Cr-4Al-0.15Zr (wt.%) was studied in t wo atmospheres: S-2 vapor over the range 4.4-25.4 Pa and H-2-H2S mixtu res corresponding to a P-S2 range 0.2-1.297 Pa in the temperature rang e 973-1373 K. It was found that the constitution of the gaseous phase is of great importance on the corrosion kinetics and the morphology of the corrosion products. Furthermore, a stratification phenomenon duri ng scale growth was observed during the initial sulfidation stage in H -2-H2S mixtures containing a sufficiently high H2S partial pressure. T his behavior was not observed during tests in pure-sulfur vapor.