Thermal shock resistance of in situ formed SiC–BN composites

SiC–BN ceramic matrix composites (SiC–BN CMCs) were in situ synthesized, using Si3N4, B4C and carbon as reactants. Thermal shock resistance of in situ SiC–BN composites was investigated by measuring strength retention after varying temperature difference (ΔT) up to 1100 °C and compared with that of monolithic SiC. Monolithic SiC showed rapidly drop in flexural strength above ΔT of 900 °C, while SiC–BN composites showed an increase or negligible reduction in flexural strength till ΔT equal to 1100 °C, showing a great improvement of thermal shock resistance.