| 摘要 |
Annular brake disc preform ( 15 ), wherein 40 to 80 layers of reinforcement fibers of at least two different lengths ( 11, 19 ) ranging from 10-60 mm are distributed in a planar gradient throughout the body of the preform, with the reinforcement fibers located near the exterior planes of the disc being predominately shorter fibers ( 11 ) and with the reinforcement fibers located in the central planes of the disc being predominately longer fibers ( 19 ). Also, process of making carbon-carbon composite preforms by: providing chopped pitch or PAN fibers ( 11, 19 ) of at least two different lengths; directing a robotic spraying apparatus to spray the chopped fibers into an annular mold ( 5 ) in 40 to 80 concentric iterations of chopped fiber deposition to provide a matrix of fibers in the mold; depositing a curable binder into the mold to intermix the binder with the fiber matrix; compressing the fiber matrix and curable binder within the mold; curing the binder to form a preform matrix; filling the preform matrix with pitch to form a pitch matrix; and subjecting the pitch matrix to chemical vapor deposition to form a carbon-carbon composite preform ( 15 ).
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