Microstructure, mechanical properties and thermal shock behavior of h-BN–AlN ceramic composites prepared by combustion synthesis

h-BN–SiC–AlN–TiN ceramic composites with volume content of AlN–TiN ranging from 20% to 70% were prepared by combustion synthesis from powder compacts of B4C, Si, Al and TiN under 100 MPa nitrogen pressure. The volume fraction of AlN–TiN was found to have a significant influence on the microstructure, mechanical properties and thermal shock resistance of the composites. With the increasing volume content of AlN–TiN, the mechanical properties of the composites were improved remarkably, while thermal shock resistance decreased. Thermal shock tests showed that the critical thermal shock temperature (ΔT) was higher than 1200 °C for the composites with AlN–TiN contents of 30 vol%; while it was decreased to 850 and 670 °C for the composites with AlN–TiN contents of 50 and 70 vol%, respectively.