A compact material with a laminated structure similar to the structure of nacre has been successfully made using a procedure described in this paper. This laminated structural design provides high-fracture toughness to Si3N4/BN-Al2O3 ceramic composites. The dense Si3N4 laminate (99.6% of theoretical density) had a flexural strength of 500 Mpa and a fracture toughness of 15 MPa·m1/2. The introduction of reinforcement (15 wt% SiC whiskers) within the Si3N4/BN-Al2O3 laminated ceramic composites further increases the strength and fracture toughness values to 650 MPa and 20 MPa·m1/2, respectively.

Keywords: Silicon nitride, laminate composites, fracture toughness, SiC whiskers