Synthesis, microstructure and mechanical properties of reactively sintered ZrB2–SiC–ZrN composites

ZrB2–SiC–ZrN composites were fabricated by reactive hot pressing using Zr, Si3N4, and B4C powders as starting materials. Sintering was conducted at temperatures of 1800 to 2000 °C under a load of 20 MPa in Ar atmosphere. The composite was densified at 2000 °C. The in situ formed BN flakes which distributed uniformly at the grain boundaries were identified by X-ray diffraction and scanning electron microscopy. The formation of h-BN phase and its effect on the mechanical properties of the composite are discussed.