Fabrication of SiC/SiC composites by means of in situ crystallization of SiC fibers

A novel challenge, the in situ crystallization of Pre-SiC reinforced-fiber during the fabrication of SiC/SiC composites, has been made for cost effectiveness by altering the conventional coating method. Constituent parts of each fabricated material with various manufacturing conditions were assessed by microscopic observation. The depending issues of a prototype process were rather serious that the unwanted areas were conspicuously observed as several forms, such as a residual oxide area, unsintered area, course matrix, porosity along the fiber-tows, and a huge scale of deformation on fiber-tows. Crystallization process of Pre-SiC fiber itself caused volume contraction of about 24.5%, which result in the formation of a gap between the fiber-tow and pyrolytic carbon (PyC) interface. Crucial design parameter is determined as the amount of PyC, a large amount of that will cause irregular stress on fiber bundles during hot-pressing. The successful fabrication improvement, based on the control of dominant parameter and defects, shows that the known defects are rarely observed in the final product of composite material.