THE SULFIDATION OF Fe-Y ALLOY IN H_2-H_2S MIXTURES AT HIGH TEMPERATURE
YAN Renyun; NIU Yan; WU Weitao(State Key Laboratory for Corrosion and Protection of Metals; Institute of Corrosion and Protection of Metals;The Chinese Academy of Sciences; Shenyang 110015)orrespondent: YAN Renyun; Tel: (021)56648715; Fax: (021)56783825
Cite this article:
YAN Renyun; NIU Yan; WU Weitao(State Key Laboratory for Corrosion and Protection of Metals; Institute of Corrosion and Protection of Metals;The Chinese Academy of Sciences; Shenyang 110015)orrespondent: YAN Renyun; Tel: (021)56648715; Fax: (021)56783825. THE SULFIDATION OF Fe-Y ALLOY IN H_2-H_2S MIXTURES AT HIGH TEMPERATURE. Acta Metall Sin, 1998, 34(8): 880-887.
Abstract The corrosion of two iron-based alloys containing 15% and 30% yttrium in H2-H2S mixtures under 10-3 Pa S2 at 600-800℃ was studied to establish whether yttrium additions can improve the sulfidation resistance of pure Fe. the presence of yttrium is beneficial,but not as much as expected. In fact, the corrosion rate of iron is considerably reduced by the yttrium addition, but the two alloys were corroded still much more rapidly than pure yttrium. The sulfidation kinetics of pure yttrium are rather irregular, while the corrosion rate of pure iron and the two alloys tends to become parabolic after an hailal period of variable length. Under all conditions the two alloys form an external FeS layer, overlying an intermediate region of complex composion colltaining a mixture of the compounds of the two metals and an innermost region of internal attack. Thus, iron can still diffuse through the intermediate region to form the outer FeS layer with non-neglible rate. The scaling behavior of these alloys is discussed by taking into account the presence of intermetallic Fe-Y compounds and the limited solubility of yttrium in iron.
