Lun Huilin, Zeng Yi, Xiong Xiang, Zhao Lei, Li Dongling, Ye Ziming, Qian Tianxiao
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
Beijing Key Laboratory of Metal Material Characterization, Beijing 100081, China.
Materials (Basel). 2019 Jun 13;12(12):1909. doi: 10.3390/ma12121909.
Hexagonal boron nitride/silicon carbide (-BN/SiC) ceramics were fabricated by a spark plasma sintering (SPS) method. Phase and microstructure of ceramics were characterized and observed, respectively, using the X-ray diffraction, scanning electron microscope and electron probe microanalysis. The effect of molar ratios of SiC to -BN on the microstructure, relative density, hardness, thermal conductivity, and the heating rate by microwaves on the ceramics were investigated. The results showed that the orientation of flake-like -BN was significantly influenced by SiC content in -BN/SiC ceramics. With the increasing of SiC content, the -BN flakes gradually became an isotropic distribution from the preferred orientation aligning in a SPS pressure direction. The relative density of -BN/SiC ceramics was 97.6 ± 0.9% at a molar ratio of SiC to -BN of 40/60 mol%. The preferential orientation of -BN flakes contributed to a relatively high thermal conductivity along the SPS pressure direction, which was beneficial to increasing the heating rate of -BN/SiC ceramics in microwave fields.
采用放电等离子烧结（SPS）法制备了六方氮化硼/碳化硅（-BN/SiC）陶瓷。分别利用X射线衍射、扫描电子显微镜和电子探针微分析对陶瓷的相和微观结构进行了表征和观察。研究了SiC与-BN的摩尔比对陶瓷微观结构、相对密度、硬度、热导率以及微波加热速率的影响。结果表明，-BN/SiC陶瓷中片状-BN的取向受SiC含量的显著影响。随着SiC含量的增加，-BN薄片逐渐从沿SPS压力方向择优取向变为各向同性分布。当SiC与-BN的摩尔比为40/60 mol%时，-BN/SiC陶瓷的相对密度为97.6±0.9%。-BN薄片的择优取向有助于沿SPS压力方向具有较高的热导率，这有利于提高-BN/SiC陶瓷在微波场中的加热速率。
