Abstract: The invention relates to an electrolysis installation comprising at least two rows of electrodes that are immersed at least in part in a liquid electrolyte giving off one or more gaseous species of corrosive nature at the electrodes, at least one separation membrane being disposed between two adjacent rows of electrodes. Each membrane is constituted by carbon fiber reinforcement stiffened by a carbon matrix and presents porous portion that is permeable to ions and impermeable to the or each gaseous species, given off at the electrolytes.

Abstract: A reinforcing fiber texture for a composite material part is made by multi-layer three-dimensional weaving with a satin type weave or a multiple satin type weave. The texture comprises at least three layers of weft yarns T interlaced by warp yarns C, each warp yarn taking hold in alternation of one weft yarn in n from a first layer of weft yarns and of one weft yarn in n of a second layer of weft yarns adjacent to the first, the number n being an integer not less than 3. The paths of the warp yarns are similar and they are offset in the warp direction.

Abstract: Thermostructural composite structure having a compositional gradient, formed from a porous core (5) made of a refractory having a pore volume content of greater than or equal to 80%. The core (5) lies between two intermediate layers (6a, 6b) comprising the carbon fiber reinforcement, densified by a matrix composed of the carbon phase and of a ceramic phase, and a refractory solid filler. Two monolithic ceramic shells (7a, 7b) cover the intermediate layers in order to give stiffness to the entire structure.

Abstract: An environmental barrier is formed on a substrate (10) of ceramic matrix composite material and comprises an outer anticorrosion protection layer (12) containing a compound of the type comprising an aluminosilicate of an alkali, or an alkaline-earth, or a rare-earth element. A bond sub-layer (14) is formed between the substrate (10) and the protection layer (12), the composition of the bond sub-layer varying from substantially pure silicon to substantially pure mullite between an inner face beside the substrate and an outer face, with the silicon content decreasing and the mullite content increasing.

Abstract: The invention relates to a device for supporting electrodes in an electrolysis installation, said support comprising a busbar having electrodes fastened thereto, said electrodes being disposed on either side of the busbar and extending vertically below said busbar, the busbar and said electrodes being designed to be immersed at least in part in an electrolyte that gives off one or more gaseous species of a corrosive nature. The device further comprises a protective element of carbon/carbon material placed under the busbar, the protective element being of length and width that are not less than the length and the width of the busbar.

Abstract: The invention relates to a method of fabricating a part including at least one face in the form of a surface of revolution from a structure made up of a plurality of thin-walled hollow bodies. In order to ensure that cutting takes place without damaging the walls and/or the bonds between the walls of the hollow bodies, the part is machined in the structure by means of a water jet. More precisely, during machining, the structure is attacked with a jet of water under pressure that is directed tangentially relative to the outer envelope of said at least one face to be made in the form of a surface of revolution.

Abstract: Within the pores of a porous thermostructural composite material, there is form an aerogel or xerogel made up of a precursor for a refractory material, the precursor is transformed by pyrolysis to obtain an aerogel or xerogel of refractory material, and then it is silicided by being impregnated with a molten silicon type phase. The aerogel or xerogel is formed by impregnating the composite material with a composition containing at least one organic, organometalloid, or organometallic compound in solution, followed by in situ gelling. The method is applicable to improving the tribological properties or the thermal conductivity of C/C or C/SiC composite material parts, or to making such parts leakproof.

Abstract: A composite material part is made by forming a fiber preform (20), forming holes (22) extending within the preform from at least one face thereof, and densifying the preform with a matrix formed at least in part by a chemical vapor infiltration (CVI) type process. The holes (22) are formed by removing material from the preform with fibers being ruptured, for example by machining using a jet of water under pressure, the arrangement of the fibers in the preform with the holes being substantially unchanged compared with the initial arrangement before the holes were formed. This enables the densification gradient to be greatly reduced, and it is possible in a single densification cycle to obtain a density that, in the prior art, required a plurality of cycles separated by intermediate scalping.

Abstract: The invention provides a method of making a fiber ply for forming a preform of a composite part in the form of a body of revolution having a non-developable surface, the method being characterized in that it comprises the steps consisting in: defining an annular space (23) with first and second canvases (20, 21) respectively defining an inner periphery and an outer periphery thereof; placing fibers between the canvases (20, 21) by placing the fibers in the annular space in at least one direction and by holding said fibers on the canvases by stitching; implementing circular connection stitching in the vicinity of the inner periphery of the annular space (23); and cutting out the fiber ply as made in this way in the annular space (23) in order to extract it from the canvases.

Abstract: Within the pores of a porous thermostructural composite material, there is form an aerogel or xerogel made up of a precursor for a refractory material, the precursor is transformed by pyrolysis to obtain an aerogel or xerogel of refractory material, and then it is silicided by being impregnated with a molten silicon type phase. The aerogel or xerogel is formed by impregnating the composite material with a composition containing at least one organic, organometalloid, or organometallic compound in solution, followed by in situ gelling. The method is applicable to improving the tribological properties or the thermal conductivity of C/C or C/SiC composite material parts, or to making such parts leakproof.

Abstract: The invention relates to a roller comprising an axial support element made of metal and comprising at least two shafts, and a cylindrical shell made of thermostructural composite material. In order to compensate for differential expansion between the metal axial support element and the cylindrical shell made of thermostructural composite material, radial clearance is provided with the axial support element and the cylindrical shell.

Abstract: A part made of a porous material containing carbon, in particular a C/C composite material, is protected against oxidation by being impregnated with a composition in an aqueous medium containing at least a phosphorous compound, elemental titanium, and boron or a boron compound other than titanium diboride, to form in the presence of oxygen and at least one alkali or alkaline-earth element M that catalyses oxidation of carbon, at least one P—O—Ti-M type association bonded by boron oxide B2O3 and trapping the element M.

Abstract: The invention relates to a thermal erosion test device for testing thermal protection materials for use in a solid propellant thruster. The device comprises a support for holding a plate made of the thermal protection material for testing so that its faces a face of a block of solid propellant, the space between the plate and the face of the propellant block defining a combustion chamber of substantially rectangular shape, said chamber extending along said plate and opening out into a nozzle.

Abstract: The method comprises a first stage of transforming carbon precursor material into carbon by heating, with the resulting gaseous effluent being extracted continuously, and a second stage of high temperature heat treatment under low pressure with the resulting gaseous effluent being extracted continuously. The first and second stages are performed one after the other in the same oven by proceeding, after the end of the first stage, with the steps of switching the gaseous effluent outlet from the oven to interrupt a connection with a first extractor device and to establish a connection with a second extractor device, of adjusting the pressure inside the oven to the value required for the second stage, and of adjusting the heating temperature of the oven starting from the temperature reached at the end of the first stage. It is also possible to switch temperature measurement from at least one first sensor to at least one second sensor different from the first.

Abstract: An adapter device for controlling a rocket engine nozzle under conditions of external pressure that can lead to the jet separating inside the nozzle, the nozzle being fitted with a diverging portion that is movably mounted relative to a stationary portion of the nozzle, thrust deflection then being achieved by swivelling the diverging portion so as to deflect the jet of combustion gas in contact with the inside wall of the diverging portion. The device includes a structure disposed inside the diverging portion in such a manner as to reduce the diverging nature of the flow section thereof and to increase the bearing area of pressure forces exerted by the jet on the diverging portion during swivelling thereof.

Abstract: The invention relates to a method of making a casing-and-diverging-portion unit, the method comprising the following steps: forming fiber reinforcement from a first fiber preform made with a first type of fiber and a second fiber preform made with a second type of fiber different from the first type of fiber, said second preform being placed on the first preform; maintaining the fiber reinforcement in tooling so that it has a shape identical to the shape of the casing-and-diverging-portion unit that is to be made; and impregnating said fiber reinforcement with a thermosetting resin and impregnating the resin.

Abstract: Carbon nanotubes are incorporated in the fiber structure by growing them on the refractory fibers of the substrate so as to obtain a three-dimensional substrate made of refractory fibers and enriched in carbon nanotubes. The substrate is densified with a matrix to form a part of composite material such as a friction part of C/C composite material.

Abstract: The invention provides a thermal protection device for mounting on the wall of a structure to be protected, the device comprising a panel suitable for receiving high temperature heat flux on its outside face. The panel is held at a determined distance from the wall of the structure and beside its inside face there is at least one thermally insulating layer. The thermal protection device further comprises a layer made of a compressible material which is maintained in a compacted state between the wall of the structure and the thermally insulating layer. The thermally insulating layer can thus be held reliably as close as possible to the panel without generating heat conduction paths or large mechanical stresses on the panel.

Abstract: A method of making a thermally-protective coating on a thruster structure, the method consisting in: continuously measuring out and mixing (14) at least one polyurethane and a mixture of polymerization agents in which specific fillers have previously been dispersed; coating a rotating cylindrical support surface (2) by continuously casting a strip (18) of touching turns of the resulting mixture; and pre-polymerizing the resulting coating at ambient pressure so that said polyurethane becomes polymerized sufficiently to be capable of being stressed mechanically.

Abstract: Carbon bodies are heated in an oven under low pressure and while being swept with an inert gas, gaseous effluent containing elemental or compound sodium in sublimed form being continuously extracted from the oven via an effluent exhaust pipe. At least one sodium-neutralizing agent is injected into the effluent exhaust pipe immediately downstream from the outlet for exhausting gaseous effluent from the oven. The sodium-neutralizing agent is selected from carbon dioxide and steam, and it can be injected continuously into the flow of gaseous effluent.