Effect of pyrolysis temperature on the properties of three-dimensional silica fiber reinforced nitride matrix composites

Three-dimensional silica fiber reinforced nitride matrix composites (3D SiO2f/nitride composites) were prepared through four cycles of vacuum infiltration of a hybrid precursor and pyrolysis under ammonia atmosphere. The effects of pyrolysis temperature on densification behavior, mechanical properties, and microstructures of the composites were investigated. With the increase of pyrolysis temperature from 800 to 1300 degrees C, the density Of SO2f/nitride composites increased from 1.83 to 1.88 g/cm(3), while the flexural strength decreased from 148 to 53 MPa, and the elastic modulus decreased from 41.5 to 25.1 GPa. The higher temperatures cause serious damage to silica fibers. The properties of silica fibers and the reinforcing mechanism determine the mechanical properties of the composites.