Effect of Oxidative Surface and Sizing Treatments of Carbon Fiber on Tesile Strength of C/C Composites
Norio IWASHITA and Yoshihiro SAWADA
Abstract:Two pitch based high modulus type carbon fibers with oxidative surface and sizing treatments and without any treatments are used in the present work. These fibers are made under the same process derived from the same precursor. Unidirectional carbon fiber reinforced carbon composites (C/C composites) are prepared from two kinds of these carbon fibers and four kinds of carbon matrix precursors, two thermosetting resins (phenolic and furan resins) and two pitches, (coal-tar and petroleum pitches). The tensile test of the strand specimen of the composites heat-treated at different temperatures is carried out by following JIS R7601. Effects of oxidative surface and sizing treatments of carbon fiber on tensile properties of the composites derived from different matrix precursors are discussed. In the case of high modulus type pitch based carbon fiber, it is found that there is almost no effect on the strength of composites by the surface oxidation and sizing treatment of the carbon fiber, except for showing different fracture morphologies of graphitized composites derived from the thermosetting resins between the treated and the untreated fibers. Key Words:C/C composite, Oxidative surface treatment, Sizing treatment, Carbon fiber, Tensile strength