Microstructural evolution and oxidation behavior of TiB2-SiC-B4C composite fabricated by reactive spark plasma sintering

摘要

Microstructural evolution and oxidation behavior of TiB2-SiC-B4C composite fabricated from Ti-SiC-B4C system with different weight ratios via reactive SPS were investigated in detail. Based on the characterizations of SEM, XRD, TEM and HRTEM, it was found that the solid diffusion induces reactions between Ti and B4C to form TiB2(TiB), C and Ti(B,C,Si). Afterwards, the results of oxidation tests at 800 degrees C, 900 degrees C and 1000 degrees C demonstrated that the sample with highest TiB2 contents performed the best oxidation resistance due to the lowest porosity. Furthermore, the smoothly glassy oxidation layer above substrate composed of TiO2 and B2O3 became thicker with temperature increasing, meanwhile, the vaporized B2O3 recrystallized into plate-like, rose-like even large-monolithic grains. (C) 2018 Elsevier B.V. All rights reserved.