High thermal conductivity in pressureless densified SiC ceramics with ultra-low contents of additives derived from novel boron–carbon sources

• DOI: 10.1016/j.jeurceramsoc.2014.02.024
• Publication Date: 2014-03-16T05:46:00Z
• Authors: Yinsheng Li; Jie Yin; Haibo Wu; Ping Lu; Yongjie Yan; Xuejian Liu; Zhengren Huang; Dongliang Jiang
• Keywords: Carbon fibers

Abstract In order to attain high thermal conductivity, SiC was doped with ultra-low amounts of B and C as sintering additives using boric acid together with d -fructose as boron–carbon sources. The contents of in situ generated B and C were both tailored as low as 0.4 wt.%, which can significantly reduce the impurities induced phonon scattering effect. The SiC ceramics were pressureless densified at 2150 °C for 1 h, and some samples experienced subsequent annealing at 1950 °C for 4 h. High thermal conductivities of 180.94 W/(m K) for the as-sintered SiC ceramics and 192.17 W/(m K) for the annealed specimens at room temperature were achieved. The reasons for the high thermal conductivity in the polycrystalline SiC ceramics were specified, based on the close correlation with microstructure.