High Temperature Oxidation of SiC Powder in Oxidizing Atmosphere Containing Water Vapor

Abstract:

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Oxidation of SiC powder was studied at 1373 K to 1873 K in Ar-O2, Ar-H2O, and Ar-O2-H2O using thermogravimetry. At 1373 K to 1573K, the weight gain increased with increasing water vapor pressure. The oxidation rate was evaluated on the basis of the Ginstering-Brounshtein kinetic model. In this temperature region, the apparent activation energy for the oxidation was almost the same (139-191 kJmol-1) independent of the atmosphere, suggesting that the same oxidation process proceeds. On the other hand, at temperatures >1673 K, the weight gain in the dry O2 (Ar-O2) was greater than that in the wet and wet O2 (Ar-H2O and Ar-O2-H2O). The apparent activation energy in the dry O2 (442 kJmol-1) was much greater than that in the wet and wet O2. We propose that water molecule diffused in silica layer in the wet and wet O2 atmosphere at 1373 K to 1873 K.

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Periodical:

Edited by:

Katsutoshi Komeya, Yi-Bing Cheng, Junichi Tatami and Mamoru Mitomo

Pages:

197-200

DOI:

10.4028/www.scientific.net/KEM.403.197

Citation:

T. Akashi et al., "High Temperature Oxidation of SiC Powder in Oxidizing Atmosphere Containing Water Vapor", Key Engineering Materials, Vol. 403, pp. 197-200, 2009

Online since:

December 2008

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$35.00

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