CO-GRAPHITIZATION OF FIBERS AND MATRIX IN CARBON-CARBON COMPOSITES WITH CONTROLLED INTERFACES

摘要

The properties of carbon/carbon composites like others depend on the properties of the reinforcing carbon fibers, fiber architecture and matrix microstructure. The processing of these composites with alternative reinforcements and their influence on matrix microstructure are of significant interest. Carbon/carbon composites have been prepared using PAN & Pitch based stabilized fibers with PFA and binder pitch as matrix precursors. These composites have been heat treated to different temperatures in the range 550°-3000℃. Optical texture, SEM and XRD examination have been used to study development of graphitic texture and ordering in these composites as function of heat treatment. It has been observed that PAN based fibers have higher surface activity resulting in high thermal stresses in the heat treated composites than pitch based fibers. On heat treatment to >2700℃ latter composites exhibit better graphitic ordering than former composites, both the composites exhibit high degree of graphitization. However, the maximum contribution is coming from fibers themselves.