The sulfidation of Inconel 738 in H2/H2S/Ar gas mixture at 500-900°C

摘要: The sulfidation behavior of the cast nickel-base superalloy Inconel 738 (IN-738) was studied over temperature range 500–900°C in three various ratios H2/H2S/Ar atmospheres having sulfur partial pressures 10−4–102 Pa. kinetics followed parabolic rate law all cases, and rates increased with increasing pressure. In general, scales formed were heterophasic duplex, consisting an outer layer composed mostly nickel sulfides (mostly NiS Ni3S2, minor Ni7S6 detected at T > 750°C) plus some CoS2/Co3S4, CoMo2S4, NiCo2S4, chromium sulfide (Cr2S3/Cr3S4), while inner contained a mixture amounts ofA12S3 Cr2S3/Cr3S4. amount decreased that Ni3S2 temperature. dependence constants (K p ) Ps(2)(the n value) significantly higher ≥ 850°C as compared to measured lower temperatures (T ≤ 850°C).