ISSN:
1573-4889
Schlagwort(e):
sulfidation
;
Fe-25Cr-20Ni-1.5Al2O3
;
oxide dispersion-strengthened alloy
;
mixed gas corrosion
;
coal combustion/gasification
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Maschinenbau
Notizen:
Abstract The effect of minor addition of α-Al2O3 dispersoids on the sulfidation behavior of Fe-25Cr-20Ni was investigated over a range of pO2, 1.13×10−20 to 1.18×10 ****−22 atm. at constant pS2=1.22×10−8 atm. Fe-25Cr-20Ni and Fe-25Cr-20Ni 1.5 Al2O3 with and without preformed oxide scales were exposed to bioxidant gas mixtures H2/H2O/H2S/Ar at 700° C. Both isothermal and cyclic exposures were included. Scales were characterized by a combination of several surface analytical tools. A remarkable improvement in sulfidation resistance is observed in Fe-25Cr-20Ni-1.5Al2O3 under the conditions investigated here. This is attributed to the ability of the alloy to form and maintain a predominantly Cr2O3 scale with reduced Fe-diffusion and content. Possible scientific reasons for such improvement are discussed. The base alloy, Fe-25Cr-20Ni, fails to develop and retain such a Cr2O3 scale and undergoes sulfidation within a few minutes of exposure. The scale breakdown process by sulfidation is explained qualitatively. Experimental evidence suggests that sulfur in the environment enhances Fe-diffusion and content in the scale.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00662962
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