Abstract: A method of fabricating a fiber structure by multilayer three-dimensional weaving between a plurality of weft yarns and of warp yarns, the fiber structure having at least first and second portions that are adjacent in the warp direction, the first portion presenting, in a direction perpendicular to the warp and weft directions, a thickness greater than the thickness of the second portion, includes making the first portion using a step of three-dimensionally weaving warp and weft layers in which a fiber fabric is formed in the form of a Mock-Leno weave grid in a core of the first portion together with skins at a surface of the first portion, a weave of the skins being modified locally so as to deflect certain warp yarns from said skins and weave them with the fiber fabric in the form of the Mock-Leno weave grid.

Abstract: A process for densifying annular porous substrates by chemical vapour infiltration, includes providing a plurality of unit modules including a support plate on which is formed a stack of substrates, the support plate including a central gas inlet opening communicating with an internal volume formed by the central passages of the stacked substrates and gas outlet openings distributed angularly around the central opening, and a thermal mass cylinder disposed around the stack of substrates having a first end integral with the support plate and a second free end, forming stacks of unit modules in the chamber of a densification furnace, and injecting into the stacks of unit modules a gas phase including a gas precursor of a matrix material to be deposited within the porosity of the substrates.

Abstract: A process for manufacturing pyrocarbon, includes forming pyrocarbon by a calefaction process from at least one C2 to C6 alcohol or polyalcohol precursor, the precursor being ethanol, rough laminar pyrocarbon being obtained by imposing a temperature of between 1250° C. and 1325° C. during calefaction.

Abstract: A process for manufacturing a friction component made of composite material, includes the densification of a fibrous preform of carbon yarns by a matrix including at least pyrocarbon and at least one ZrOxCy phase, where 1?x?2 and 0?y?1, the matrix being formed by chemical vapor infiltration at least from a first gaseous precursor of pyrocarbon and a second gaseous precursor including zirconium, the second precursor being an alcohol or a C1 to C6 polyalcohol modified by linking the oxygen atom of at least one alcohol function to a group of formula —Zr—R3, the substituents R being identical or different, and R being selected from: —H, C1 to C5 carbon chains and halogen atoms.

Abstract: An assembly for an aircraft turbojet engine is described. The assembly includes a central gas-exhaust element and a connecting flange interposed between, upstream, a metallic outlet of a turbojet engine and, downstream, the central element. The connecting flange consists of an annular part and flexible lugs having axially: a first end where the lug is connected to the annular part, and a second free end, projecting radially outwards from the first end and towards which the lug is fixed with the central element.

Abstract: A structure for the nacelle of an aircraft propulsion unit includes a first skin and stiffeners arranged to hold acoustic treatment modules against the first skin. Each acoustic treatment module includes a honeycomb core and a second skin, such that the honeycomb core is sandwiched between the first skin and the second skin. Such a structure allows the structural reinforcement function provided by the stiffeners to be separated from the acoustic treatment function performed by the acoustic treatment modules which are simply bearing on the first skin.

Abstract: A method for densifying porous annular substrates by chemical vapor infiltration, includes providing a plurality of unit modules including a support tray on which substrates are stacked, the support tray including a gas intake opening extended by an injection tube disposed in an internal volume formed by the central passages of the stacked substrates, the injection tube including gas injection orifices opening into the internal volume, forming stacks of unit modules in the enclosure of a densification furnace and injecting, into the stacks of unit modules, a gas phase including a gas precursor of a matrix material to be deposited within the porosity of the substrates.

Abstract: A part includes a substrate having, adjacent to a surface of the substrate, at least a portion that is made of a material that contains silicon, and an environmental barrier formed on the surface of the substrate, the environmental barrier including a first layer including at least one first rare earth silicate and presenting grains with a mean size less than or equal to 1 ?m; and a second layer covering the first layer, the second layer including at least one rare earth silicate and presenting grains with a mean size greater than 1 ?m.

Abstract: A method of treating at least one silicon carbide fibre, the method including a) formation of a silica layer at the surface of a silicon carbide fibre having an oxygen content less than or equal to 1% in atomic percentage, the silica layer being formed by contacting this fibre with an oxidizing medium having a temperature greater than or equal to 50° C. and pressure greater than or equal to 1 MPa, and b) removal of the silica layer formed by hydrothermal treatment of the fibre obtained after implementation of step a) in which the fibre is treated with water at a pressure between saturating vapour pressure and 30 MPa and at a temperature less than or equal to 400° C.

Abstract: The present disclosure relates to a cell structure for an acoustic attenuation device for a nacelle of an aircraft propulsion assembly. This cell structure includes lateral partitions forming channels that each extend between a first end and a second end and skin elements arranged so that each channel is at least partly closed at the first end thereof by at least one skin element. Each skin element is connected to a respective lateral partition and can move relative to the other lateral partitions. A continuous skin can be assembled on this cell structure so as to at least partly close the channels at the second end thereof and to thus form an acoustic attenuation device.

Abstract: A method for depositing a coating on a continuous carbon or ceramic fiber from a precursor of the coating, the method including at least the heating of at least one segment of the fiber in the presence of a liquid or supercritical phase of the coating precursor by a laser beam so as to bring the surface of the segment to a temperature allowing the formation of the coating on the segment from the coating precursor.

Abstract: A process for depositing a coating on a continuous carbon or silicon carbide fibre from a coating precursor, includes at least heating a segment of the fibre in the presence of the coating precursor in a microwave field so as to bring the surface of the segment to a temperature enabling the coating to be formed on the segment from the coating precursor.

Abstract: A support tooling for porous preforms intended to be infiltrated by a molten metal includes a rack including two suspension bars each extending longitudinally along a first direction, the suspension bars being held spaced apart from one another along a second direction perpendicular to the first direction; a plurality or porous preform supports removably mounted on the suspension bars, each support including a first portion connected to one of the suspension bars by a connection sliding along a third direction perpendicular to the first and second directions and a second portion extending from the first portion and including support elements which are able to hold a porous preform by point or linear contact.

Abstract: A method for producing a consolidated fiber preform intended for the manufacture of a part made of composite material, includes shaping a fiber texture in a heated metal mold, the texture being pre-impregnated with a transient or fugitive material, or shaping a fiber texture in a metal mold and injecting a transient or fugitive material into the fiber texture held in shape in the metal mold, cooling the mold, removing the set fiber preform from the mold, coating the fiber preform with a slurry containing a powder of ceramic or carbon particles, heat-treating the coated fiber preform so as to form a porous shell around the fiber preform by consolidation of the slurry and so as to remove the transient or fugitive material present in the fiber preform, consolidating the fiber preform by gas-phase chemical infiltration.

Abstract: A process for manufacturing a fibrous preform filled with particles, includes forming the filled preform by compacting a stack of a plurality of fibrous strata impregnated by a suspension of ceramic oxide particles in a liquid medium, wherein the liquid medium includes at least one compound having a saturated vapor pressure of less than 2.3 kPa at 20° C., this compound being present in a weight content of greater than or equal to 30% relative to the total weight of the suspension.

Abstract: A fiber structure includes a plurality of weft layers and a plurality of warp layers interlinked with three-dimensional or multilayer weaving, the fiber structure including at least first and second portions that are adjacent in the warp direction, the first portion presenting thickness in a direction perpendicular to the warp and weft directions that is greater than the thickness of the second portion. The weft layers situated in the core of the first portion of the fiber structure include braids. The weft layers extending on either side of the weft layers including the braids and going as far as the skin of the first portion include yarns or strands, the braids presenting a section greater than the section of the yarns or strands.

Abstract: A method for manufacturing a part made of composite material includes injecting into a fibrous texture a slurry including at least one powder of refractory ceramic particles suspended in a liquid phase, filtering the liquid phase of the slurry and retaining the powder of refractory ceramic particles inside the texture so as to obtain a fibrous preform loaded with refractory ceramic particles, densifying the fibrous texture by treatment of the refractory ceramic particles present in the fibrous texture in order to form a refractory matrix in the texture. The method further includes, before injecting the slurry under pressure, pre-saturating the fibrous texture with a carrier fluid consisting in injecting into said texture a carrier fluid.

Abstract: A method of chemical vapor infiltration or deposition includes forming silicon carbide in pores of a porous substrate or on a surface of a substrate, the substrate being placed in a reaction enclosure, the silicon carbide being formed from a gas phase introduced into the reaction enclosure, the gas phase including a reagent compound that is a precursor of silicon carbide and that has the following formula in which n is an integer equal to 0 or 1; m is an integer lying in the range 1 to 3; p is an integer lying in the range 0 to 2 with m+p=3; and R designates —H or —CH3; a ratio C/Si between the number of carbon atoms and the number of silicon atoms in the introduced gas phase lying in the range 2 to 3.

Abstract: A sandwich panel for an aircraft turbojet nacelle includes an outer skin in contact with an air flow, an inner skin opposed to the outer skin, and an intermediate system comprising partitions connecting the inner and outer skins so as to form cells, the inner skin of at least one cell having at least one corrugation configured to allow the materials making up the sandwich panel to deform in the event of thermal variation.

Abstract: A method for manufacturing a composite panel is described. The method includes producing a first wall, a second wall, a third wall and a fourth wall from composite materials including an oxide matrix and long oxide fibres; from the first and second walls, producing a cellular core including a plurality of cells, each cell including a first end and an opposing second end, covering the first and second ends of the cells of the cellular core with the third wall and the fourth wall, respectively, so as to close the ends of said cells.