Manufacture of unidirectional carbon fiber reinforced carbon composites by preformed-yarn method

摘要

A bundle of polyacrylonitrile-based carbon fibers was included in a matrix precursor composed of fine pitch coke and mesophase pitch, and was coated with polypropylene, resulting in a preformed yarn (PY). Unidirectional (UD) PY sheets, prepared by aligning the PYs, were stacked. Hot press molding of the staked UD-PY sheets at 600℃ and heat treatment up to 2000℃ were performed to manufacture a UD-C/C composite. Density, porosity, flexural strength and modulus of the resulting UD-C/C composite test pieces were measured. Flexural strength and modulus of the UD-C/C composite test pieces manufactured from PY with 40wt% pitch coke in its matrix precursor were 487.3MPa and 125.4GPa, respectively. Even without impregnation, these value were superior by afactor of about 1.3 than the UD-C/C composites manufactured by conventional method using phenol resin as a main component of matrix precursor. Microstructural inspections of cross sections of the test pieces were also carried out. Any kind of pore werehardly recognized and a good fiber I matrix bonding was formed in the matrix of the UD-C/C composites manufactured from PY with 40wt% pitch coke in its matrix precursor.