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Effects of Mo and Al additions on the sulfidation behavior of 310 stainless steel

Journal Article · · Oxidation of Metals
; ;  [1]
  1. National Taiwan Ocean Univ., Keelung (Taiwan, Province of China). Inst. of Materials Engineering

The high-temperature sulfidation behavior of 310 stainless steel (310SS) with Mo and Al additions (up to 10 at.%) was studied over the temperature range 700--900 C in pure-sulfur vapor over the range of 10{sup {minus}3} to 10{sup {minus}1} atm. The corrosion kinetics followed the parabolic rate law in all cases and the sulfidation rates increased with increasing temperature and sulfur pressure. The sulfidation rates decreased with increasing Mo and Al contents and it was found that the addition of 10 at.% Mo resulted in the most pronounced reduction among the alloys studied. The scales formed on 310SS with Mo additions were complex, consisting of an outer layer of iron sulfide (with dissolved Cr), (Fe, Ni){sub 9}S{sub 8}, and Cr{sub 2}S{sub 3}/Cr{sub 3}S{sub 4} (with dissolved Fe), and an inner heterophasic layer of Fe{sub 1{minus}x}S, Cr{sub 2}S{sub 3}/Cr{sub 3}S{sub 4}, NiCr{sub 2}S{sub 4}, Fe{sub 1.25}Mo{sub 6}S{sub 7.7}, FeMo{sub 2}S{sub 4}, and MoS{sub 2}. The scales formed on 310SS with Mo and Al additions had a similar mixture as above, except that Al{sub 0.55}Mo{sub 2}S{sub 4} was also observed in the inner layer. The formation of MoS{sub 2} and Al{sub 0.55}Mo{sub 2}S{sub 4} partly blocked the transport of cations through the inner scale, resulting in the reduction of the sulfidation rates compared to 310SS.

OSTI ID:
655367
Journal Information:
Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 1-2 Vol. 50; ISSN OXMEAF; ISSN 0030-770X
Country of Publication:
United States
Language:
English