Silicon Carbide-Based Ceramic Materials with Boron Carbide Additives

Abstract

Materials based on silicon carbide (SiC) and the SiC–20B4C–1C–0.5B system were synthesized by spark plasma sintering. The characteristics of the powder mixtures and final materials were investigated using thermal analysis, electron microscopy, x-ray diffraction, and flexural strength testing. Thermal analysis revealed that SiC powders with boron (B) and carbon (C) additives exhibited accelerated mass loss, indicating enhanced sinterability and the formation of a grain boundary phase composed of boron–carbon compounds. The introduction of boron carbide promoted the formation of a secondary strengthening phase in the silicon carbide matrix. The primary phase of the material was the 6H–SiC polytype, which possesses a hexagonal α-SiC lattice. The mechanical testing of the SiC–20B4C–1C–0.5B composition demonstrated a flexural strength of 332 MPa at 20°C.