Method of and apparatus for making gradated density carbon-carbon components

摘要

The fabrication of a one piece solid propellant rocket motor nozzle with a gradated density includes the preparation of a braided preform (25) of carbon fibers (17-191 on a mandrel (10) in a multidimensional pattern, layer upon layer, until the desired thickness is attained, and the application of multiple impregnation, carbonization and graphitization redensification cycles, specifically high pressure impregnation carbonization (HIPIC) reden­sification comprising immersion of the preform and mandrel in a liquid impregnant and the application of pressure to impregnate the preform following which the preform is carbonized and graphitized to convert the impregnant to a carbon matrix, with the level of liquid impregnant adjusted in the successive redensification cycles such that the region of the preform corresponding to the throat of the nozzle receives four complete re- densification cycles to reach a density of 1.9 g/cc, the cone entrance three cycles for a 1.7 g/cc density and the cone exit for two cycles for a 1.5 g/cc density.