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 catalyzes oxidation of carbon, at least one P—O—Ti-M type association bonded by boron oxide B2O3 and trapping the element M.

Abstract: A turbine nozzle element including an inner annular platform sector, an outer annular platform sector, and at least one vane extending between the platform sectors and connected to both of them. The nozzle element includes a single piece of composite material including fiber reinforcement densified by a matrix that is at least partially ceramic, and the fiber reinforcement includes a fiber structure that is woven by three-dimensional or multi-layer weaving, and that presents continuity throughout the volume of the nozzle element and throughout the periphery of the vane.

Abstract: A reinforcing fiber structure woven as a single piece for fabricating a composite material part, the fiber structure having an internal portion or core (72), and a portion adjacent to an outside surface of the structure, or skin (74, 76), and the fiber structure being formed by a three-dimensional weaving in its core using at least one weave selected from an interlock weave and a multilayer weave, and by weaving at its skin with a weave of satin type that is different from the weave in the core the weaving at the skin being of the multilayer type or of the two-dimensional type.

Abstract: A fiber preform is obtained by conforming panels of fiber texture on a former having a surface that reproduces the shape desired for a surface of the nozzle or the nozzle divergent section that is to be made. The panels are bonded together via their mutually contacting edges. A consolidated fiber reinforcement is formed by shaping the fiber preform impregnated with a consolidation composition including a resin. The shaping of the fiber preform is performed between the former and a jacket applied against the impregnated fiber preform so as the consolidated fiber reinforcement has a fiber volume percentage of at least 35%, and a thickness of less than 5 mm over at least a major fraction of its axial dimension. The densification of the fiber reinforcement is continued by chemical vapor infiltration after pyrolyzing the resin so that once densified, a part is obtained that has practically the shape and the wall thickness of the nozzle or the nozzle divergent section that is to be made.

Abstract: The invention relates to a mixer (100) for a separate-stream nozzle of a turbojet, the mixer being designed to mix a hot inner stream from the combustion chamber of the turbojet with a cold outer stream from the fan of the turbojet. The mixer comprises an inner shroud (120) defining a flow channel for said hot inner stream, an outer shroud (110) disposed around the inner shroud (120) and co-operating therewith to define a flow channel for said cold outer stream, and a lobed structure (130) having lobes (1321, 1322) extending longitudinally from the trailing edges (110a, 120a) of said shrouds. The lobed structure (130) is made of a ceramic matrix composite material and is attached to the outer shroud (110) by flexible fastener tabs (140).

Abstract: A method of fabricating a lobed structure for a gas turbine flow mixer having an annular upstream portion extended downstream by a portion forming a multilobed skirt, the method comprising: making a fiber preform (100) out of refractory fibers and having a shape corresponding to the shape of the lobed structure to be fabricated, from a plurality of component elements of fiber texture that are assembled together and shaped by means of tooling of a shape corresponding to the shape of the lobed structure to be fabricated so as to obtain an assembled fiber preform having a first preform portion (111) corresponding to the annular portion of the lobed structure and a second preform portion (112) corresponding to the multilobed skirt of the lobed structure, the component elements of the fiber preform being assembled together at least in part along connection lines (121) extending substantially in the flow direction of the flow past the lobes of the multilobed skirt preform portion; and densifying the assembled an

Abstract: A method of fabricating a thermostructural composite material part includes making a fiber preform formed of yarns or tows and impregnated by a consolidating composition containing a carbon- or ceramic-precursor, transforming the carbon- or ceramic-precursor by pyrolysis, and then densifying the preform by chemical vapor infiltration. A consolidating composition is used that additionally contains refractory solid fillers in the powder form presenting mean grain size less than 200 nanometers and leaving, after pyrolysis, a consolidated solid phase in which the carbon or the ceramic derived from the precursor occupies a volume representing 3% to 10% of the apparent volume of the preform, and the solid fillers occupy a volume representing 0.5% to 5% of the apparent volume of the preform.

Abstract: A packing structure according to the invention for a fluid contacting column forms a volume comprising an ordered arrangement of bundles of tubes of diameter ranging between 5 and 50 mm. The walls of the tubes comprise orifices which promote circulation and mixes fluids in the structure. The orifices are inscribed in rectangles whose sides range between 2 and 45 mm, and each one of the orifices extends over a surface area greater than 2 mm2.

Abstract: A method of making a fiber structure by multilayer three-dimensional weaving, the fiber structure having a thickness in a direction perpendicular to the warp and weft directions that varies along the warp direction while conserving the same number of warp yarns that are woven at all points of the fiber structure along the warp direction, wherein during a transition in the warp direction from a first portion of the fiber texture to a second portion of the fiber texture having a thickness that is greater than the thickness of the first portion, the number of warp planes is decreased and the number of layers of warp yarns is increased without changing the number of warp yarns, by constituting at least one warp plane in the second portion with warp yarns taken from at least two different warp planes in the first portion.

Abstract: A turbine ring assembly for a gas turbine, the assembly having a complete ring forming a single piece of ceramic matrix composite material (CMC), a metal structure for supporting the CMC ring having metal annular supports between which the CMC ring is placed while allowing differential expansion at least in a radial direction between the CMC ring and the annular supports, an arrangement for centering the CMC ring, and at least one element for preventing turning of the CMC ring about its axis.

Abstract: To densify thin porous substrates (1) by chemical vapor infiltration, the invention proposes using loading tooling (10) comprising a tubular duct (10) disposed between first and second plates (12, 13) and around which the thin substrates for densification are disposed radially. The tooling as loaded in this way is then placed inside a reaction chamber (20) in an infiltration oven having a reactive gas admission inlet (21) connected to the tubular duct (11) to enable a reactive gas to be admitted into the duct which distributes the gas along the main faces on the substrates (1) in a flow direction that is essentially radial. The reactive gas can also flow in the opposite direction, i.e. it can be admitted into the tooling (10) from its outer envelope (16) and can be removed via the duct (11).

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: A fiber reinforcing texture woven as a single part for fabricating a composite material part having an inner portion, or core, made by three-dimensional weaving with yarns made up from discontinuous fibers, and a portion adjacent to an outside surface, or skin, made by weaving with yarns made up from continuous filaments.

Abstract: The invention relates to an exhaust system (100) for channeling the streams from a by-pass gas turbine, the system comprising a stream channeling nozzle and an exhaust casing (110) for connecting the channeling nozzle to the outlet of the gas turbine, said channeling nozzle comprising a primary nozzle (120) fastened to the exhaust casing (110) and a secondary nozzle (130) placed around the primary nozzle. The exhaust system further comprises means for fastening the secondary nozzle (130) directly to the exhaust casing (110), said secondary nozzle being supported by the exhaust casing independently of the primary nozzle (120).

Abstract: The invention relates to a method of making a refractory carbide layer on the accessible surface of a C/C composite material, the method including a step consisting in placing the composite material in contact with a reactive composition in solid form that contains an atomic proportion greater than or equal to one-third and less than or equal to 95% of a metal that is a precursor of a determined carbide having a melting temperature greater than 2000° C., and an atomic proportion of silicon that is greater than or equal to 5% and less than or equal to two-thirds. The method further includes a step consisting in impregnating the accessible surface of the C/C composite material with the reactive composition melted at a temperature that is greater than or equal to the melting temperature of the metal that is a precursor of a determined carbide.

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 fiber reinforcing texture (10) woven as a single part for fabricating a composite material part having an inner portion (12), or core, made by three-dimensional weaving with yarns made up from discontinuous fibers, and a portion (14, 16) adjacent to an outside surface, or skin, made by weaving with yarns made up from continuous filaments.

Abstract: A turbine ring assembly for a gas turbine includes a one-piece split ring (10) of ceramic matrix composite (CMC) material, a CMC wedge-shaped part (20) having flanks in contact with the ends of the ring, on either side of the split, so as to close the ring, and an annular metal support structure (40) surrounding the CMC ring and in contact therewith over the major fraction of its outline, the CMC ring being mounted with prestress in the metal structure, at least one element (26) exerting a resilient return force on the wedge-shaped part to keep it in contact with the ends of the CMC ring when the split opens under the effect of differential expansion between the annular metal structure and the CMC ring, and at least one element for preventing the CMC ring from turning about its axis.

Abstract: The method comprises: using chemical vapor infiltration to form a first continuous interphase on the fibers of a fiber structure made of refractory fibers, the interphase having a thickness of no more than 100 nanometers; impregnating the fiber structure with a consolidation composition comprising a carbon or ceramic precursor resin; forming a fiber preform that is consolidated by shaping the impregnated fiber structure and using pyrolysis to transform the resin into a discontinuous solid residue of carbon or ceramic; using chemical vapor infiltration to form a second continuous interphase layer; and densifying the preform with a refractory matrix. This preserves the capacity of the fiber structure to deform so as to enable a fiber preform to be obtained that is of complex shape, while nevertheless guaranteeing the presence of a continuous interphase between the fibers and the matrix.

Abstract: The invention relates to a structuring assembly (13) for an exhaust nozzle, including the following main elements: (a) an outer skin (22) including a non-acoustic portion (33); (b) an inner structuring skin (23); (c) an acoustic structure (21) including cells (27) having a cellular core, said acoustic structure being arranged between the outer skin (22) and the inner structuring skin (23), at least one of said main elements being made of a composite material, and the acoustic structure (21) being supported between the outer skin (22) and inner structuring skin (23) by linking means (31; 41) attached to the inner structuring skin (23) and to the non-acoustic portion (33) of the outer skin (22) so as to transfer the stresses onto the inner structuring skin (23) and the non-acoustic portion (33) of the outer skin (22). The invention also relates to an exhaust nozzle for a nacelle, comprising such a structuring assembly (13), as well as to a nacelle.