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http://dx.doi.org/10.4191/kcers.2011.48.5.426

Oxidation of CVD β-SiC in Impurity-Controlled Helium Environment at 950℃  

Kim, Dae-Jong (Department of Nuclear Materials Development, Korea Atomic Energy Research Institute)
Kim, Weon-Ju (Department of Nuclear Materials Development, Korea Atomic Energy Research Institute)
Jang, Ji-Eun (Department of Materials Engineering, College of Engineering, Chungnam National University)
Yoon, Soon-Gil (Department of Materials Engineering, College of Engineering, Chungnam National University)
Kim, Dong-Jin (Department of Nuclear Materials Development, Korea Atomic Energy Research Institute)
Park, Ji-Yeon (Department of Nuclear Materials Development, Korea Atomic Energy Research Institute)
Publication Information
Journal of the Korean Ceramic Society / v.48, no.5, 2011 , pp. 426-432 More about this Journal
Abstract
The oxidation behavior of CVD ${\beta}$-SiC was investigated for Very High Temperature Gas-Cooled Reactor (VHTR) applications. This study focused on the surface analysis of the oxidized CVD ${\beta}$-SiC to observe the effect of impurity gases on active/passive oxidation. Oxidation test was carried out at $950^{\circ}C$ in the impurity-controlled helium environment that contained $H_2$, $H_2O$, CO, and $CH_4$ in order to simulate VHTR coolant chemistry. For 250 h of exposure to the helium, weight changes were barely measurable when $H_2O$ in the bulk gas was carefully controlled between 0.02 and 0.1 Pa. Surface morphology also did not change based on AFM observation. However, XPS analysis results indicated that a very small amount of $SiO_2$ was formed by the reaction of SiC with $H_2O$ at the initial stage of oxidation when $H_2O$ partial pressure in the CVD ${\beta}$-SiC surface placed on the passive oxidation region. As the oxidation progressed, $H_2O$ consumed and its partial pressure in the surface decreased to the active/passive oxidation transition region. At the steady state, more oxidation did not observable up to 250 h of exposure.
Keywords
Oxidation; SiC; VHTR; Helium;
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Times Cited By KSCI : 1  (Citation Analysis)
Times Cited By SCOPUS : 1
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