Preparation of SiCf/SiC Composites with Low Porosity by Liquid Composite Moulding-Pyrolysis Process

Traditionally, Polymer infiltration and pyrolysis (PIP), chemical vapor infiltration (CVI) and melt infiltration (MI) are main processes to fabricate continuous silicon carbide fiber reinforced silicon carbide matrix (SiCf/SiC) composites, one of attractive potential high temperature structural materials. However, long preparation period and high porosity are still problems for further applications. Especially, porosity is crucial to the mechanical properties. Liquid composite moulding-pyrolysis (LCMP) used liquid SiC precursor to decrease the open porosity to 5% with no more than 11 cycles of infiltration and pyrolysis. Mechanical properties like bending strength was investigated with different thickness of pyrolitic carbon (PyC) interface and pyrolysis cycles. The bending strength reached 585 MPa with 200 nm PyC interface under 1200°C pyrolysis temperature. Thus, LCMP process offers exciting opportunities to improve performance of SiCf/SiC composites.