This paper deals with Si-Ti-C-0 fiber-bonded ceramics (Tyrannohex~R) produced by hot-pressing the sheets or woven cloth of pre-oxidized Si-Ti-C-0 fiber covered with a surface oxide (SiO_2 and TiO_2) layer. Tyrannohex showed a close-packed structure with fiber volume fraction of 90 percent, and the interstices were perfectly filled with an oxide material, in which very fine TiC particle are uniformly dispersed. It was considered that the TiC particle was formed by the reaction between the TiO_2, which was one component of the oxidized surface layer, and excess carbon in the raw fiber itself during hot-pressing. Moreover, an interfacial carbon layer (10 approx 20 nm) was formed around all the fibers. Tyrannohex showed both high fracture energy (approx 9000 J/m~2) and high interiaminar shear strength (about 80 MPa). Uni-directional Tyrannohex showed elastic behavior to almost maximum load, and two-directional Tyrannohex also showed a relatively high proportional limit (approx 130 MPa) up to high temperature in air. Both type of Tyrannohex showed excellent creep-resistance up to 1673 KAPPA in air. Moreover, by replacing the starting fiber with lower oxygen Tyranno fiber (Lox E), high temperature properties of Tyrannohex up to 1873 KAPPA could be improved.
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