Mechanical properties of CMC using Si-Zr-C-O fiber with carbon layer formed by heat treatment in CO atmosphere

A ceramic matrix composite (CMC) containing Si-Zr-C-O fibers with a surface carbon layer formed by heat treatment in CO atmosphere was studied. The th ickness of surface carbon layer on Si-Zr-C-O fiber increased by adding 0.1% CO2 in CO atmosphere, compared with that formed in pure CO atmosphere. The flexural strength of the CMC containing the Si-Zr-C-O fibers with carbon l ayer increased with increasing the thickness of the carbon layer. This resu lt indicated that the formation of a carbon layer by heat treatment on the Si-Zr-C-Q fibers is a suitable way for modifying the interface structure of CMC.