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Surface Oxidation Mechanisms of Molybdenum Disilicide in High-Temperature Combustion Environments

Published online by Cambridge University Press:  25 February 2011

Wen-Yi Lin
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
Robert F. Speyer
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
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Abstract

The stability of MoSi2 was studied at 1600°C in combustion products with an incoming gas to air ratio of 1:6.7 and compared to results in a 1:10 environment. Oxidation was investigated using periodic weight measurements and characterization using XRD, SEM, and EDS. Passive oxidation was observed; MoSi2 was oxidized by H2O and CO2 to form Mo5 Si3 and SiO2. The amorphous silica product formed a surface layer and reduced the oxidation rate as it coarsened. MoO3(g) did not form which was in agreement with the thermodynamic (SOLGASMIX-PV) prediction that it would only form in the presence of molecular oxygen. A good agreement was observed between the measured and calculated weight gains based on the surface layer thickness.

Type
Research Article
Copyright
Copyright © Materials Research Society 1994

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References

[1] Vasudévan, A.K. and Petrovic, J. J., Mater. Sci. Eng. A155, 1 (1992).Google Scholar
[2] Hsu, J.Y., Sundaram, S.K., Lin, W.-Y., and Speyer, R.F., in Advances in Fusion and Processing of Glass, edited by Varshneya, A.K., Bickford, D., and Bihuniak, P.P., (American Ceramic Society, Ohio, 1993) p. 73.Google Scholar
[3] Lin, W.-Y., Hsu, J.Y., Berta, Y.B., and Speyer, R. F., Part I, accepted for publication in Am. Ceram. Soc. Bull., 1994.Google Scholar
[4] Berkowitz-Mattuck, J.B., Rossetti, M., and Lee, D.W., Metall. Trans. 1, 479 (1970).Google Scholar
[5] Bartlett, R.W., McCamont, J.W., and Gage, P.R., J. Am. Ceram. Soc. 48, 551 (1965).Google Scholar
[6] Fitzer, E., in Corrosion and Corrosive Degradation of Ceramics, edited by Tressler, R.E., and McNallan, M. (American Ceramic Society, Ohio, 1990) p. 19.Google Scholar
[7] Berkowitz-Mattuck, J.B., J. Electrochem. Soc. 112, 583 (1965).CrossRefGoogle Scholar
[8] Lin, W.-Y., Hsu, J.Y., and Speyer, R. F., submitted to J. Am. Ceram. Soc. for publication, 1993.Google Scholar
[9] Eriksson, G., Chem. Scr. 8, 100 (1975).Google Scholar
[10] Chase, M.W. Jr., Davies, C.A., Downey, J.R. Jr., Frurip, D.J., McDonald, R. A., and Syverud, A.N., JANAF Thermochemical Tables, 3rd ed. Parts I and II, (American Chemical Society, Washington DC, 1985).Google Scholar
[11] Thompson, W.T., Pelton, A.D., and Bale, C.W., Calphad. 7, 113 (1983).Google Scholar
[12] Reed, R.J., North American Combustion Handbook, Vol. I, 3rd ed. (North American Mfg. Co., Ohio, 1986) p. 12.Google Scholar