The microstructure and mechanical properties of Si-Ti-C-O and Si-Zr-C-O fiber-bonded ceramics, produced by hot-pressing a laminated material of pre-oxidized Si-(Ti or Zr)-C-O fibers, were investigated. The Si-Ti-C-O fiber-bonded ceramic had a close-packed structure of fibers with a volume fraction of 85% and a SiO2-based oxide matrix including TiC particles. On the other hand, the Si-Zr-C-O fiber-bonded ceramic consists of a close-packed structure with a volume fraction of 83% and a SiO2-based oxide matrix without any precipitated phase. Moreover, an interfacial carbon layer is constructed around all the fiber elements in both the fiber-bonded ceramics during the hot-pressing. The high-temperature flexural strength was much higher in the Si-Ti-C-O fiber-bonded ceramic than in the Si-Zr-C-O one. This was thought to be due to the SiO2-matrix in the Si-Ti-C-O fiber-bonded ceramic, which seems to be refrained from the softening effect by dispersed TiC particles at high temperature.
