서브마이크론/나노 크기의 SiC 비율변화에 따른 ZrB2-SiC 세라믹스의 열적, 기계적 특성

Abstract

ZrB₂-SiC ceramics are fabricated via hot pressing with different ratios of submicron or nano-sized SiC in a ZrB₂-20 vol%SiC system, in order to examine the effect of the SiC size ratio on the microstructures and physical properties, such as thermal conductivity, hardness, and flexural strength, of ZrB₂-SiC ceramics. Five different ZrB₂-SiC ceramics (ZrB₂-20 vol%[(1-x)SiC + xnanoSiC] where x = 0.0, 0.2, 0.5, 0.8, 1.0) are prepared in this study. The mean SiC particle sizes in the sintered bodies are highly dependent on the ratio of nano-sized SiC. The thermal conductivities of the ZrB₂-SiC ceramics increase with the ratio of nano-sized SiC, which is consistent with the percolation behavior. In addition, the ZrB₂-SiC ceramics with smaller mean SiC particle sizes exhibit enhanced mechanical properties, such as hardness and flexural strength, which can be explained using the Hall-Petch relation.