ISSN:
1573-4889
Keywords:
sulfidation
;
Fe−Mo−Al−Mn
;
Fe−Mo−Al−Mn−Y
;
Fe−Mo−Al−Mn−Zr
;
Al2O3, Al0.55Mo2S4
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The effects of zirconium and yttrium additions on the sulfidation behavior of an Fe−10Mo−20Al−8Mn(a/o, atom percent) alloy were examined in flowing H2/H2S gas of 4Pa sulfur partial pressure at 900°C. Good scale protection was obtained during the initial reaction stage of the base alloy. However, after 7–8 hr, the formation of internal (Mn,Fe) Al2S4 platelets triggered breakdown of the protective scale. The reaction products of the zirconium-containing alloy were nonprotective. Yttrium addition resulted in an Y(Fe1−xAlx)12 network along the alloy ferrite grain boundaries. Preferential sulfidation of this phase led to almost complete manganese depletion from the engulfed ferrite, and consequently avoided the manganese-promoted scale breakdown.After an even slower initial stage, this alloy sulfidized at a parabolic rate two orders of magnitude slower than that of pure iron. The protection during the initial and following stages was believed to be provided by an Al2O3-containing layer and an Al0.55Mo2S4+FexMo6S8−z layer, respectively. The formation of Al2O3 is thought to be due to oxygen impurities in the H2S gas, which cannot be removed by conventional means.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01046762
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