Influence of Interfacial Carbon-Layer on Mechanical Properties of Si-Ti-C-O Fiber-Bonded-Ceramic Material

Mechanical properties of Si-Ti-C-O fiber-bonded-ceramic materials synthesized from pre-oxidized Si-Ti-C-O fibers with a surface oxide layer of 90 to 190nm in thickness were investigated. The Si-Ti-C-O fiber-bonded-ceramic material was synthesized by hot-pressing the pre-oxidized Si-Ti-C-O fiber at 2123K under 50 MPa. Flexural strength and fracture toughness of the Si-Ti-C-O fiber-bonded-ceramic material increased with an increase in the thickness of the oxide layer, whereas the inter-laminar-shear strength decreased under the same condition. These changes were considered to be due to differences in formation condition of the interfacial carbon layer formed by the excess carbon which was isolated from the Si-Ti-C-O fiber during hot-pressing. Moreover, the interfacial carbon layer was found to be formed when the rawmaterial's fiber with a thick surface oxide layer was used.