Formation of carbon coating on SiC fiber for two-dimensional SiCf/SiC composites by electrophoretic deposition

Carbon coating was formed on SiC fibers in the cloth by electrophoretic deposition method using commercial colloidal graphite suspension, and mechanical properties of SiCf/SiC composites fabricated by sheet stacking method and hot-pressing were investigated. Furthermore, the effectiveness of carbon coating on SiC fiber for SiCf/SiC composite was investigated. Graphite particles partially existed on the SiC fibers after dip-coating or vacuum infiltration, and carbon coating was non-uniform on SiC fibers. In the case of electrophoretic deposition, the surface of SiC fibers was wholly coated with flaky graphite particles, and graphite particles were infiltrated into fiber bundle by electrical force, and relatively homogeneous carbon coating was also formed on not only SiC fibers at the surface of the bundle but also fibers at the center of the bundle. This homogeneous carbon coating provided the optimum interface between fiber and the matrix, and promoted large amount of fiber pullout during fracture.