<i>In Situ</i> Reaction Synthesis of Silicon Carbide–Boron Nitride Composite from Silicon Nitride–Boron Oxide–Carbon

Abstract

This work proposes a new approach, based on the reaction Si 3 N 4 + 2B 2 O 3 + 9C → 3SiC + 4BN + 6CO, to synthesize an SiC–BN composite. The composite was prepared by reactive hot pressing (RHP), at 2000°C for 60 min at 30 MPa under an argon atmosphere, following a 60 min hold at 1700°C without applied pressure before reaching the RHP temperature. TG‐DTA results showed that a nitrogen atmosphere inhibited denitrification somewhat and retarded the reaction rate. The chemical composition of the obtained material was consistent with theoretical values. FE‐SEM observation showed that in situ ‐formed SiC and BN phases were of spherical morphology with very fine particle size of ∼100 nm.