Abstract: This invention relates to a process for manufacturing a refractory material, a protective coating, and uses of this process and this coating. The process comprises the following steps: a) deposit on the surface of a substrate or in a mould a first dispersion containing at least one metallic compound chosen from among borides, carbides and borocarbides containing at least one transition metal, in powder form, and a resin with a coke mass content equal to at least 30% after carbonization; b) dry the resulting deposit; c) cross-link the resin; d) carbonize the resin under an inert atmosphere; e) cover the deposit with a second dispersion containing Si in powder form and a binder; f) heat the deposit to a temperature greater than or equal to the melting temperature of Si, under an inert atmosphere. Applications: manufacture of propulsion parts and fuselage and wing elements for aerospace and aeronautical applications; manufacture of heat exchangers for thermal power stations; metallurgy; chemical industry; etc.

Abstract: The invention concerns a composit material with a glass-ceramic or ceramic matrix obtained by the sol-gel process and reinforced by fibers, wherein said matrix is MLAS matrix and wherein said fibers are at least 17% by volume Si-Ti-C-O fibers. FIG. 2 shows the flexural stress-strain curves (compression and tension) for a composite material containing 24% by volume of Si-Ti-C-O fiber in a MLAS matrix. Shaped articles produced from the composit material according to this invention can be used in the aeronautical and spatial industries and in motor vehicle engines.

Abstract: The invention is related to a heat treatment method for silicon and carbon-containing ceramic fibers as well as fibers of the same nature with a laminated structure and having an external carbon layer.The processing method for the invention comprises a heat treatment in vacuum, during at least three hours and at a temperature of about 1000.degree. C. This treatment yields fibers surrounded with a layer of endogenic SiO.sub.2, that is itself coated with a layer of endogenic carbon.Said fibers can be used to make composite materials with fiber reinforcement.

Abstract: A method of manufacturing a composite material formed of a fibrous reinforcement and a silica based ceramic or vitro-ceramic matrix. The method includes impregnating the fibrous reinforcement by means of a sol-gel process wherein premature crystallization of the matrix obtained from the sol is hindered by addition to the sol of a crystallization retarding agent, and hot pressing the resulting material. The composite material formed has a residual porosity without the addition of nucleating agents of about less than 10%.