MECHANICAL-PROPERTIES OF OXIDATION-RESISTANT SIC C COMPOSITIONALLY GRADED GRAPHITE MATERIALS/

Mechanical properties of oxidation-resistant SiC/C compositionally gra ded graphite materials composed of a CVD SiC coating layer, a SiC/C gr aded layer, and a graphite substrate were studied by bending, compress ive, and hardness tests at room temperature. CVD SiC coated graphite a nd graphite with a SiC/C graded layer alone were also examined, The be nding strengths of oxidation-resistant SiC/C compositionally graded gr aphite materials as well as CVD SiC coated graphite were about twice a s much as that of graphite. The bending and compressive strengths of g raphite with the SiC/C graded layer alone were almost the same as thos e of graphite, The higher strengths of graphite with the CVD SiC layer can be mainly due to the CVD SiC strength itself, and partly due to t he smooth CVD surface, No effect of the SiC/C layer on the strengths w as discussed in terms of porosity, surface morphology, and the strengt h of SiC.