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Sulfidation properties of Fe‐6.1 at.% Mo alloy at 973–1273 K
Author(s) -
Elrefaie F. A.,
Smeltzer W. W.
Publication year - 1987
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19870380906
Subject(s) - sulfidation , alloy , sulfide , iron sulfide , kinetics , materials science , metallurgy , duplex (building) , sulfur , high temperature corrosion , corrosion , layer (electronics) , chemistry , analytical chemistry (journal) , crystallography , composite material , physics , quantum mechanics , dna , biochemistry , chromatography
Sulfidation of an Fe‐6.1 at% Mo alloy was investigated in H 2 S‐H 2 atmospheres, 10 −4 ⩽ P s 2 ⩽ 10 2 Pa, at 973‐1273 K. The reaction kinetics are parabolic except at 1273 K as liquid sulfide formation leads to catastrophic corrosion. This solid‐liquid transformation between Fe 2 Mo 2 S 4 and Mo 2 S 3 occurs at 1214 ± 9 K. At 1073 K and P s 2 = 10 −4 Pa, growth of a duplex Mo 2 S 3 /FeMo 2 S 4 scale offers high resistance to sulfidation. At 973, 1073 and 1173 K, 10 −2 ⩽ P s 2 ⩽ 10 2 Pa, parabolic sulfidation kinetics of the same magnitude as for pure iron describe growth of a duplex scale composed of an inner (FeMo 2 S 4 + Mo 2 S 3 ) layer and at an outer FeS layer. Marker measurements indicated that growth of the inner two‐phase layer was supported by inward migration of sulfur and that growth of the outer FeS layer resulted from outward migration of iron.