J. Korean Ceram. Soc. > Volume 49(6); 2012 > Article
 Journal of the Korean Ceramic Society 2012;49(6): 608. doi: https://doi.org/10.4191/kcers.2012.49.6.608
 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 ABSTRACT 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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