Abstract: An element made of a reinforced low density heat protective material including an elastomer and/or a silicon resin matrix loaded with organic and/or inorganic components, wherein the reinforcement is formed of glass or ceramic thread sections or the like or organic materials fitted in the mass of the matrix along directions approximately orthogonal to at least one of the faces of the element and being flush, at least at one of their extremities, with at least one of the faces. The method for obtaining this element, includes, after molding to the general dimensions and shapes of the element with the aid of a loaded silicon matrix, placing the thread sections by stitching.

Abstract: A mandrel for manufacturing a hollow composite material body. The mandrel is formed by a homogeneous graphite felt block whose fibers are embedded in a pyrolysis carbon matrix. The densification of the arrangement of fibers forming the hollow body is carried out in a neutral atmosphere.

Abstract: A mandrel for manufacturing a hollow composite material body. The mandrel is formed by an homogeneous graphite felt block whose fibers are embedded in a pyrolysis carbon matrix. The densification of the arrangement of fibers forming the hollow body is carried out in a neutral atmosphere.

Abstract: This material, essentially characterized in that it is flexible, employs simultaneously the two phenomena of in tumescence and endothermicity to obtain optimal protection characteristics maintaining the element to be protected at a temperature below or in the order of 150.degree. C. when it is subjected to thermal attack corresponding to a flame temperature of 700.degree. to 1000.degree. for a duration of at least one hour for a thickness of the material between 10 and 20 mm, comprises a binder (silicone elastomer) in a proportion of 30 to 35% by weight; a reinforcing charge (a metal oxide compatible with said silicone elastomer) in a proportion of 17 to 23% by weight; an active charge (an intumescent agent) in a production of 38 to 45% by weight; and an insulative charge in a proportion of 5 to 10% by weight, these proportions being relative to the total weight of said material.

Abstract: A process for the production of a composite material with matrix and reinforcing fibers of carbon. The process comprises: (a) forming a porous substrate (2) of carbon fibers; (b) covering the surface of each fiber wih a fine silicon carbide coating (6) by chemical vapor deposition; (c) shaping the substrate; (d) embedding the substrate in a carbon matrix (4) containing at most 20% by weight siliconcarbide; (e) covering the outer surface of the matrix with an outer silicon carbide covering (10) which contains cracks (12); and (f) filling the cracks in the outer covering with at least a borosilicate glass (16).

Abstract: Composite material with matrix and reinforcing fibres of carbon and its production process.The composite material according to the invention comprises a substrate (2) of carbon fibres covered with a fine silicon carbide coating (6) and embedded in a carbon matrix (4) containing 2 to 10% by weight silicon carbide, an outer silicon carbide covering (10), followed by a first filling of the cracks with silica (14) and a second filling with borosilicate glass (16) (SiO.sub.2 -B.sub.2 O.sub.3).This unoxidizable material can in particular be used as a heat shield for a spacecraft.