In Situ Reaction of B2O3 with AlN and/or Si3N4 to Form BN-Toughened Composites

摘要: BN-toughened oxide matrix composites were formed by the in situ reaction of B/sub 2/O/sub 3/ with Si/sub 3/N/sub 4/ and/or AIN. A low-temperature transient liquid phase aids densification at <1000/sup 0/C, and process tends to produce an intrinsically homogeneous microstructure. Mechanical properties microstructure compared those prepared conventional means from BN powders. Fracture toughness flexural strength nearly isotropic ranged 2.82 3.66 MPa . m/sup 1/2/ 130 320 MPa, respectively, Young's moduli 100 110 GPa. Densities achieved 90% 97% estimated theoretical densities. The values are intermediate extreme for anisotropic hot-pressing mixed