Study on Thermal Shock Behavior of SiC/BN Laminated Ceramic Composites

In this paper,the thermal shock resistance behavior of SiC/BN laminated ceramics was investigated by water quench test,and compared with that of SiC monolithic ceramics.The experimental results show that the thermal shock resistance critical temperature,ΔT_c,was 300℃,which was less than that of SiC monolithic ceramics.When ΔT ΔT_c,the bending strength of SiC/BN laminated ceramics slightly decreased with increasing ΔT,while the bending strength of SiC monolithic ceramics decreased steeply with increasing ΔT.The experimental result coincided with the thermal shock parameter R and R calculated values based on thermal shock fracture and thermal shock damage.The results reveal that the thermal shock crack initiation resistance of the materials was slightly less than that of SiC monolithic ceramics,but while the crack propagation resistance was much higher than that of SiC monolithic ceramics.SiC/BN laminated ceramics show excellent thermal shock behavior due to the high fracture energy resulting from crack deflection and crack absorbing at the BN weak interface.