| 950℃ 불순물을 포함한 헬륨 환경에서 CVD β-SiC의 산화 |
| 김대종, 김원주, 장지은1, 윤순길1, 김동진, 박지연 |
한국원자력연구원 원자력재료개발부
1충남대학교 재료공학과 |
| Oxidation of CVD β-SiC in Impurity-Controlled Helium Environment at 950℃ |
| Dae-Jong Kim, Weon-Ju Kim, Ji-Eun Jang1, Soon-Gil Yoon1, Dong-Jin Kim, Ji-Yeon Park |
Department of Nuclear Materials Development, Korea Atomic Energy Research Institute
1Department of Materials Engineering, College of Engineering, Chungnam National University |
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| ABSTRACT |
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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. |
| Key words:
Oxidation, SiC, VHTR, Helium |
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