ETS-synthesized Hi-Nicalon fiber–SiC matrix composite

Tough ceramic matrix composites, such as SiC/SiC, require a compliant reinforcement/matrix interface coating. The deposition of desired interface coatings on small diameter fibers in SiC/SiC composites is a substantial challenge and costly. A new carbon-rich source gas, ethyltrichlorosilane (ETS), was used to fabric SiC/SiC composite with eight harness satin-woven Hi-Nicalon fabric cloth as reinforcement by the chemical vapor infiltration (CVI) process. A graphite fiber/matrix interlayer was spontaneously formed in the material from the ETS during the CVI matrix densification process, resulting in the composite having a sound interfacial shear stress of 86 MPa. The composite showed a high proportional limit stress of 450±65 MPa and an ultimate flexural strength of 567±75 MPa, coupled with ductile fracture behavior. This study indicates that the costly interfacial coating process might be omitted when ETS is used as source gas for SiC/SiC composite.