Patent ID: 6068930
Filing Date: 2000-05-30
Classification: C04B,Y10S,Y10T

Abstract:
A method of making a thermostructural composite material comprising carbon or carbon-coated fiber reinforcement and having increased ability to withstand oxidation, in which method a matrix is formed by chemical vapor infiltration within the fiber reinforcement at least in part in a sequenced manner, alternating formation of a layer of a relatively flexible anisotropic material capable of deflecting any cracks reaching it, and a layer of a relatively rigid ceramic material, said relatively flexible anisotropic material having a rigidity less than that of the relatively rigid ceramic material, the method being characterized in that:each of a plurality of elementary sequences of the matrix comprising a relatively flexible layer of the relatively flexible anisotropic material and a relatively rigid ceramic layer, and wherein each of the plurality of elementary sequences is formed with a thickness that increases starting from the reinforcing fibers as preparation of the matrix progresses, with the total thickness of at least the elementary matrix sequence deposited first on the fibers being selected to be sufficiently small to cover the fibers in essentially individual manner; andthe relatively flexible layers of the relatively flexible anisotropic material are made of one or more anisotropic materials having sufficient capacity for elastic deformation in shear and transversely, and, while conserving a mainly ceramic character for the matrix, the thickness of the relatively flexible layers is selected to be large enough for them to be capable of absorbing differential expansion of the components of the material while it is being made, without inducing therein the existence of an initial network of cracks.