Fabrication and characteristic of nextel 720 fiber-reinforced silicon nitride matrix composites by chemical vapor infiltration process

Most current processes for fiber-reinforced silicon nitride composites are conducted at very high temperature, which is not possible to use oxide fiber as reinforcement. Here, low-temperature process of chemical vapor infiltration (CVI) was utilized to fabricate Nextel 720 oxide fiber tow-reinforced silicon nitride matrix composite with PyC as interphase. The tensile strength was analyzed by Weibull distribution. The microstructure showed that there were two types of interface bonding. The strong interface bonding determined the unexpected low strength of the composites. This indicated that the suitable interface design is the urgent issue for oxide fiber-reinforced silicon nitride composite by CVI.