Effects of heat treatment in a wet hydrogen atmosphere on the reliability of sintered {alpha}-silicon carbide
- Seoul National Univ. (Korea, Republic of). Dept. of Inorganic Materials Engineering
- Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
Sintered {alpha}-SiC was exposed, for times up to 2 h, to a flowing wet H{sub 2} atmosphere (P{sub H{sub 2}O} = 1 {times} 10{sup {minus}4} MPa) at temperatures of 1,300, 1,400, and 1,500 C. The effect of such conditions on the reliability of the ceramic was estimated by comparing the Weibull modulus of the groups of specimens, tested in four-point flexure, before and after exposure. The Weibull modulus of as-polished specimens was 6.7, indicating a wide variation in room-temperature flexural strength. The Weibull modulus was increased to 14.2 by the heat treatment for 2 h in wet H{sub 2} at 1,400 C. The average strength was also improved from 347 to 446 MPa by such exposure. Heat treatment at 1,300 and 1,500 C also improved the reliability of the material, as indicated by increases in the Weibull modulus, but to less a degree than did exposure at 1,400 C. The increases in reliability and average strength were attributed to the blunting of surface flaws by the formation of a thin SiO{sub 2} layer on the sample surface.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 82638
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 6 Vol. 78; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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