Fabrication of SiC/h-BN composite ceramics by plasma activated sintering

SiC/20% (volume fraction) h-BN composite ceramics were fabricated by the hot pressing (HP) and plasma activated sintering (PAS) methods. The density, Vickers hardness, and bending strength of the composites were tested. The microstructures and phase compositions of the composites were identified by scanning electron microscopy and X-ray diffraction. The comparison and optimized mechanism of HP and PAS were investigated. The results show that the performance of composite fabricated at 1600°C for 3 min by PAS is similar to that of composite fabricated at 1850°C for 1 h by HP; the sintering efficiency of PAS is much greater than that of HP. With 20% micrometer h-BN, the h-BN on the crystal boundary of SiC grains can inhibit the growth of SiC grain, so the effect of inhibiting grain growth in PAS rapid sintering is restrained.