Effects of precoating on mechanical properties and microstructures of 3D SiO2f/Si3N4 composites using polyhydridomethylsilazane

Polyhydridomethylsilazane was used as a preceramic polymer to fabricate three-dimensional quartz fiber reinforced silicon nitride-based composites, and the effects of precoating process on the mechanical properties and microstructures of the composites were mainly investigated. The composite without precoating process exhibited a brittle fracture surface without fiber pull-out, leading to a low flexural strength of 56.3 MPa, while the composite with precoating treatment showed a non-brittle fracture behavior with long fiber pull-out in the fracture surface, resulting in a high flexural strength of 114.5 MPa. It was the controlled fiber/matrix interface due to the precoating of the quartz fiber preform that contributed to the high mechanical property of the composite.