Interfacial morphology of PAN-CVI carbon-carbon composite

In the present PAN-CVI composite, the CVI carbon deposit exhibited two distinctive morphologies: an isotropic morphology immediately adjacent to the fiber-matrix interface and a highly oriented morphology. In the anisotropic carbon many slit-shaped microfissures were formed and the basal planes were highly oriented. The isotropic layer was composed of small, almost randomly oriented crystallites and, in this region, the microfissures were absent. It was found that the development of a well bonded carbon fiber-CVI interface depends more on CVI structure than on the type of fiber.