R-curve behavior of laminated SiC/BN ceramics

Laminated SiC/BN ceramics with a perfect layered structure was fabricated by tap-casting process and hot-pressing sintering. Damage resistance and R-curve behavior of laminated SiC/BN ceramics were evaluated using the indentation-strength-in-bending technique, and compared with those of monolithic SiC ceramics. The results showed that the indentation strengths for monolithic SiC ceramics decreased steeply with indentation load, while for laminated SiC/BN ceramics reduced slightly with indentation load, suggesting an exceptional damage resistance. Moreover, a rising R-curve behavior was demonstrated for laminated SiC/BN ceramics, a plateau R-curve behavior for monolithic SiC ceramics. The excellent damage resistance and pronounced R-curve behavior of laminated SiC/BN ceramics were attributed to crack deflection, crack branching and crack delamination at the SiC/BN weak interfaces.