Abstract: A process for obtaining a solid form containing heat-stabilized borazane is described. The solid form is capable of generating hydrogen by thermal decomposition or by a self-maintained combustion reaction. Within the solid form containing borazane, the borazane is heat-stabilized. It has thus been heat-stabilized by making an oxidized layer at its surface.

Abstract: A method of fabricating a sound attenuation panel of curved shape, the method including impregnating a fiber structure defining a cellular structure with a ceramic precursor resin; polymerizing the ceramic precursor resin while holding the fiber structure on tooling presenting a curved shape corresponding to the final shape of the cellular structure; docking the cellular structure with first and second skins, each formed by a fiber structure impregnated with a ceramic precursor resin, each skin being docked to the cellular structure before or after polymerizing the resin of the skins; pyrolyzing the assembly constituted by the cellular structure and the first and second skins; and densifying the assembly by chemical vapor infiltration.

Abstract: A pyrotechnic process for providing very high purity hydrogen, includes the combustion of at least one solid pyrotechnic charge capable of generating hydrogen-containing gas for the production of a pressurized hot hydrogen-containing gas that contains at least 70% by volume of hydrogen; and the purification of at least one portion of the pressurized hydrogen-containing gas, by passing through a metallic hydrogen separation membrane maintained at a temperature above 250° C., in order to obtain, at the outlet of the membrane, a hydrogen-containing gas that contains at least 99.99% by volume of hydrogen.

Abstract: A lightning protection device for placing on a structure for protecting, and including a first coating including at least one layer of conductive paint; and a second coating deposited on the surface coating and including a material that is thermally insulating and electrically conductive.

Abstract: A composite material part having a matrix made of ceramic, at least for the most part, is fabricated by a method including making a fiber preform from silicon carbide fibers containing less than 1 at % oxygen; depositing a boron nitride interphase on the fibers of the preform, deposition being performed by chemical vapor infiltration at a deposition rate of less than 0.3 ?m/h; performing heat treatment to stabilize the boron nitride of the interphase, after the interphase has been deposited, without prior exposure of the interphase to an oxidizing atmosphere and before depositing matrix layer on the interphase, the heat treatment being performed at a temperature higher than 1300° C. and not less than the maximum temperature to be encountered subsequently until the densification of the preform with the matrix has been completed; and thereafter, densifying the perform with a matrix that is made of ceramic, at least for the most part.

Abstract: A part made of ceramic matrix composite material has fiber reinforcement of carbon or ceramic fibers and a majority-ceramic sequenced matrix having first matrix layers made of crack-deflector material alternating with second matrix layers made of ceramic material. An interphase coating is interposed between the fibers and the matrix, and the interphase coating adheres to the fibers and to the matrix, and is formed of at least one sequence constituted by a first elementary layer made of carbon, possibly doped with boron, surmounted by a second elementary layer made of ceramic. The outer elementary interphase layer of the coating is a ceramic layer having an outer surface formed by ceramic grains of size lying essentially in the range 20 nm to 200 nm, with the presence of grains of size greater than 50 nm conferring roughness on the outer surface ensuring mechanical attachment with the adjacent matrix phase.

Abstract: A turbine engine blade made of composite material including fiber reinforcement densified by a matrix is fabricated by a method including: performing three-dimensional weaving to make a single-piece fiber blank; shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for a blade root and an airfoil, at least one second portion forming a preform for a blade inner platform or for wipers of a blade outer platform, and at least one third portion forming a preform for reinforcing a blade inner platform or for overhangs of a blade outer platform; and densifying the fiber preform with a matrix to obtain a composite material blade having fiber reinforcement constituted by the preform and densified by the matrix, and forming a single piece with an inner and/or outer platform incorporated therein.

Abstract: A fiber preform for a turbine ring sector obtained by three-dimensional weaving and including a base-forming first portion, two tab-forming L-shaped portions each presenting two branches, two ends of the first portion being extended by respective ones of the first branches, and a second portion connecting together the two tabs, first and second strips woven together forming the first branches, a first fraction of the thicknesses of the second branches, and the first portion, there being a non-linked zone between them that is situated in the first branches and in the first portion, and a third woven strip forming the second portion and a second fraction of the thickness of the second branches of each of the tabs.

Abstract: A method of assembling together by brazing two parts made of composite material, each part having an assembly face for brazing with the assembly face of the other part, the method including: making a plurality of cavities in the assembly face of at least one of the two composite material parts, at least some of the cavities opening out into one or more portions of the part that are situated outside the assembly face; interposing capillary elements between the assembly faces of the composite material parts; placing a brazing composition in contact with a portion of the capillary elements; and applying heat treatment to liquefy the brazing composition so as to cause the molten brazing composition to spread by capillarity between the assembly faces of the composite material parts.

Abstract: The invention relates to a method for the treatment of silicon carbide fibers, comprising a step involving the chemical treatment of fibers with an aqueous acid solution containing hydrofluoric acid and nitric acid but free of acetic acid in order to remove the silica present on the surface of fibers and to form a layer of microporous carbon. The invention also relates to a method for the production of a fibrous preform, comprising the formation of a fibrous structure comprising treated silicon carbon fibers and the use of said preform for the production of a part made from composite material.

Abstract: A modulator device for modulating a gas ejection section, includes a shutter member for partially shutting a nozzle throat, a control guide of the shutter member, a main piston, and a primer piston. The control guide is movable between a retraction position for retracting the partial shutter element relative to the nozzle throat and a shutting position in which the partial shutter element is in contact with the nozzle throat. The primer piston is movable between a rest position and a priming position for priming the main piston when the pressure in the modulator device reaches a first predetermined value. The main piston is movable between a first position for locking the control guide against movement in its retraction position, and a second position for locking the control guide when the pressure in the modulator device reaches a second predetermined value less than the first predetermined value.

Abstract: A nozzle of variable throat section for an aerospace vehicle thruster, the nozzle including a cylindrical housing presenting a throat of aperture diameter less than the diameter of the housing, and a needle suitable for sliding inside the housing between a high discharge rate front position in which the nose is set back from the throat of the housing, and a low discharge rate rear position in which the nose is in abutment against the throat, the needle including a rod for sliding inside the housing of the nozzle, the rod terminating in a nose of decreasing diameter. The nose of the rod is suitable for coming into abutment against the throat of the nozzle housing forming a seat and includes at least two axial grooves formed in its outer periphery to allow gas to pass when the nose is axially in abutment against the throat of the housing of the nozzle.

Abstract: A turbine engine blade of composite material comprising fiber reinforcement obtained by multilayer weaving of yarns and densified by a matrix. The blade has a first portion constituting an airfoil forming a single piece with at least one second portion constituting a blade root. The fiber reinforcement portions corresponding to the first and second portions of the blade are mutually interleaved, at least in part, with yarns of the second fiber reinforcement portion penetrating into the first fiber reinforcement portion.

Abstract: A part made of oxide/oxide composite material includes fiber reinforcement constituted by a plurality of warp yarn layers and of weft yarn layers interlinked by three-dimensional weaving, with the spaces present between the reinforcing yarns being filled with a refractory oxide matrix. The fiber reinforcement presents a weave selected from the following weaves: interlock; multi-plain; multi-satin; and multi-serge, with warp and weft thread counts lying in the range 4 yarns/cm to 20 yarns/cm. The fiber reinforcement also presents a fiber volume fraction lying in the range 40% to 51%.

Abstract: A turbine nozzle comprises a plurality of composite material vanes, each vane comprising an inner platform, an outer platform with attachment tabs on the outside, and at least one airfoil extending between the inner and outer platforms and secured thereto. The attachment tabs of the vanes are engaged on a metal assembly ring supporting all of the vanes, extending continuously along the outer platforms of adjacent vanes, and forming a distinct assembly part between the vanes and a turbine casing.

Abstract: A device for attaching blades to a rotor disk of a turbine engine is provided. The device includes: a rotor disk provided at its outer periphery with a plurality of slots, each slot being formed between two adjacent disk teeth and extending axially between front and rear faces of the disk; a plurality of blades, each having a respective root mounted in a slot of the disk; and at least one pin mounted in the rotor disk to pass through the roots of at least two adjacent blades and extending between the front and rear faces of the rotor disk so as to attach the blades to the rotor disk.

Abstract: A method for fabricating turbine engine blade or vane made of composite material includes: performing three-dimensional weaving to make a single-piece fiber blank; shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for at least a blade/vane airfoil, at least one second portion forming a preform for an inner part of a blade/vane inner platform or for an outer part of a blade/vane outer platform, and at least one third portion forming a preform for an outer part of a blade/vane inner platform or for an inner part of a blade/vane outer platform; and densifying the fiber preform with a matrix to obtain a composite material blade, and forming a single piece with an inner and/or outer platform(s) incorporated therein.

Abstract: A combined steering and drag reduction device for a missile is disclosed. The device includes a base and an upper part which are arranged in succession along a main axis of navigation of the missile. Advantageously, the device also includes a pressurized-gas generator and at least one lateral thruster having at least one nozzle configured to deliver a thrust, by expanding gas transmitted by the generator and oriented along an axis substantially perpendicular to the main axis. The at least one lateral thruster also has at least one stabilizing chamber configured to expand the gas transmitted by the generator and expel it through an outlet section of the base substantially perpendicular to the main axis.

Abstract: The invention relates to a triggered-stroke actuator (10) comprising a body (12) housing a piston (14) and a rod (16), and a gas generator (18) mounted in said body (12) opposite said piston (14) and capable of pressurising a first chamber (20) defined between said gas generator and said piston, in which the piston (14) comprises, on its external face, a groove (30) in which is housed a sealing joint (40) with the body (12) of the actuator (10). A calibrated passage (50), adapted to evacuate gas from the first chamber (20), is formed between the sealing joint (40) and the wall of the groove (30).

Abstract: A paste kneading device includes an oblong barrel, two shafts arranged parallel within the barrel, being held and driven at their first ends, defining an upstream end, by a drive device, two screws each formed by threads carried by the shafts, each screw having a transport section carrying a main thread to cause the paste to advance along the two screws, and an outlet orifice formed in the wall of the barrel to discharge the kneaded paste, the kneading device further including a holder device to hold each shaft at its second end, defining a downstream end, and enabling the shaft to rotate freely, the holder device including, for each shaft, a first portion secured to the shaft and a second portion secured to a cap end portion of the barrel, the cap end portion being removable and the first and second portions being configured to engage and disengage freely.