US Patent 7867596 Wet friction member

A carbon fiber composite material (10) is provided which includes carbon fibers (11), a matrix (12) binding the carbon fibers (11) together, and pores (13), and a volume fraction of the carbon fibers (11) exclusive of the pores (13) is not less than 45% and up to 80%. The carbon fiber composite material (10) may preferably have a porous structure of which a porosity is not more than 20% and up to 70%. This carbon fiber composite material (10) has a high static friction coefficient (μS), and low μ ratio, and thus is suitable for a wet friction member (e.g., carbon disc 5) which is excellent in both of static friction performance and dynamic friction performance.