| 고압 환경에서 소결 온도에 따른 MgO 물성의 변화 |
| 송정호, 노윤영, 송오성 |
| 서울시립대학교 신소재공학과 |
| Property of MgO with Different Sintering Temperatures under High Pressures |
| Jeongho Song, Yunyoung Noh, Ohsung Song |
| Department of Materials Science and Engineering, University of Seoul |
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| ABSTRACT |
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We investigated the property changes of MgO powders sintered at temperatures ranging from $700^{circ}C$ to $1900^{circ}C$ for 5minutes at a pressure of 2.7 GPa for a high-pressure high-temperature(HPHT) diamond synthesis process. The physical properties of the sintered MgO powders were characterized by optical microscopy, field emission scanning electron microscopy (FE-SEM), Vickers hardness tests, and by the apparent density, and X-ray diffractometry. An optical micro-analysis showed that white MgO powders became black after sintering due to carbon contamination from the graphite heat source. FE-SEM revealed the growth in the grain size of the MgO powders from $0.3{mu}m$ to $50{mu}m$ after sintering at $1700^{circ}C$. The hardness and apparent density increased to $1800^{circ}C$ while the samples were dedensified at $1900^{circ}C$ due to the growth of isolated pores. According to the XRD analysis, no phase transformation occurred in the MgO powders. These results suggest that HPHT-sintered MgO powders can show an accelerated sintering process characterized by grain neck growth, pore connections, isolated pore growth and dedensification in 5 minutes, while these processes with the conventional sintering process take at least 5 hours. |
| Key words:
MgO, HPHT sintering, XRD, Vickers hardness, Dedensification |
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