Low‐temperature Pr <sub>3</sub> Si <sub>2</sub> C <sub>2</sub> ‐assisted liquid‐phase sintering of SiC with improved thermal conductivity
Jie Xu, Xiaobing Zhou, Shunrui Zou, Lu Chen, Peter Tatarko, Jian‐Qing Dai, Qing Huang, Qing Huang
Abstract
Abstract A novel Pr 3 Si 2 C 2 additive was uniformly coated on SiC particles using a molten‐salt method to fabricate a high‐density SiC ceramics via liquid‐phase spark plasma sintering at a relatively low temperature (1400°C). According to the calculated Pr–Si–C‐phase diagram, the liquid phase was formed at ∼1217°C, which effectively improved the sintering rate of SiC by the solution–reprecipitation process. When the sintering temperature increased from 1400 to 1600°C, the thermal conductivity of SiC increased from 84 to 126 W/(m K), as a consequence of the grain growth. However, an increasing amount of the sintering additive increased the interfacial thermal resistance, resulting in a decrease of thermal conductivity of the materials. The highest thermal conductivity of 141 W/(m K) was obtained for the material having the largest SiC grains and an optimized amount of the additive at the grain boundaries and triple junctions. The proposed Pr 3 Si 2 C 2 ‐assisted liquid‐phase sintering of SiC can be potentially used for the fabrication of SiC‐based ceramic composites, where a low sintering temperature would inhibit the grain growth of SiC fibers.