MECHANICAL PROPERTIES AND MICROSTRUCTURE OF SiO₂-AlN COMPOSITES

SiO₂-AlN composites were prepared by hot-pressing process. Mechanical properties of SiO₂ matrix can be greatly improved after incorporating AlN particles. Flexural strength and fracture toughness of SiO₂-AlN composites with 30 vol% AlN particles sintered at 1400℃ reached 200 MPa and 2.96 MPa·m^1/2 respectively. XRD analysis indicated that no chemical reaction occurred between SiO 2 matrix and AlN particles suggesting that SiO₂ matrix had excellent chemical compatibility with AlN particles. Microstructure of the as-sintered composites was investigated with SEM and TEM analysis. The relationship among the phase composition and microstructure and mechanical properties was discussed.