Abstract: A part includes a substrate, having, adjacent to a surface of the substrate, at least a portion that is made from a material that contains silicon, and an environmental barrier formed on the surface of the substrate, the environmental barrier including at least a first layer including a rare earth disilicate of formula REa2Si2O7 present at a molar content lying in the range 70% to 99.9%, where REa is a rare earth element; and at least one rare earth oxide of formula REb2O3 present at a molar content lying in the range 0.1% to 30%, where REb is a rare earth element different from REa.

Abstract: A turbomachine turbine nozzle extending around a central axis, including at least one radially outer shroud, at least one radially inner shroud, and at least one blade made of ceramic matrix composite material, distinct from the radially inner shroud and from the radially outer shroud, and extending radially between the radially inner shroud and the radially outer shroud, the blade being hollow and including a cavity opening at a radially inner end and at a radially outer end of the blade, the nozzle including at least one tubular mast arranged in the cavity of the blade and allowing routing the ventilation air passing through the cavity of the blade, the mast including a radially outer end attached to the radially outer shroud, and a radially inner end cooperating with a radial flange for positioning the radially inner shroud.

Abstract: The present disclosure relates to an apparatus for fluidised-bed chemical vapour deposition from a gaseous phase allowing the temperature of the fluidised bed to be stabilised during the deposition and also to an associated method for its implementation, the apparatus being characterised in that it comprises a porous thermal insulator present in an inlet zone and configured to be passed through by the gaseous phase, said porous thermal insulator having an effective thermal conductivity at 20° C. less than or equal to 3.5 W·m-1·K-1.

Abstract: A method for densifying one or more porous substrates with pyrolytic carbon by chemical vapour infiltration, includes admitting, at the inlet of the densification furnace, a reactive gaseous phase including at least one pyrolytic carbon precursor; reacting at least a fraction of the reactive gaseous phase with the porous substrate or substrates; extracting, at the outlet of the densification furnace, gaseous effluents originating from the reactive gaseous phase; reintroducing, with the reactive gaseous phase admitted at the inlet of the densification furnace, at least a fraction of the gaseous effluents extracted at the outlet of the furnace, wherein the fraction of the gaseous effluents introduced with the reactive gaseous phase includes at least one polyaromatic hydrocarbon compound.

Abstract: The invention relates to the production of a composite material of a lobed structure (10) of a flow mixer which comprises a portion having a plurality of lobes (17, 19). For this purpose, a fibrous preform containing a resin will be produced in a simple geometric configuration of developable revolution. This is an intermediate state. By exploiting the thermoformable or thermosetting nature of the resin, the geometry of this intermediate preform is modified to deform it with limited offsets towards the final geometry.

Abstract: A method for injecting a loaded suspension into a fibrous texture having a three-dimensional or multilayer weaving includes the injection of a suspension containing a powder of solid particles into the volume of the fibrous texture. The injection of the loaded suspension is carried out by at least one hollow needle in communication with a loaded suspension supply device, each needle being movable in at least one direction extending between a first face and a second opposite face of the fibrous texture so as to inject the loaded suspension at one or more determined depths in the fibrous texture.

Abstract: A turbine stator blade made of ceramic matrix composite material includes a hollow blade profile and has a trailing edge and a leading edge, the blade including a first portion including an extrados face and a second portion distinct from the first portion including an intrados face, the first and second portions being connected to one another by a connection interface present at least on the trailing edge or leading edge, the connecting interface including a region of overlap between the first and second portions present on at least one longitudinal end of the blade profile and intended to be present outside a flow path of a gas stream of the turbine, the blade also including a platform present at a longitudinal end of the blade profile and that includes a first portion integral with the extrados face and a second part integral with the intrados face.

Abstract: A method for producing a hollow part made of a ceramic matrix composite material. The method includes shaping a hollow fibrous preform. A core of oxidizable material is housed or inserted into the preform. The method also includes consolidating the preform and extracting the core by oxidising the core.

Abstract: An assembly for a turbomachine turbine includes a housing (1) extending circumferentially about an axis X, sectors (2) intended to form a ring capable of delimiting a gas flow path, each sector (2) comprising a first side (17) and a second side (18) extending radially and circumferentially about the said axis X and spaced axially from each other, each side (17, 18) of the sector (2) including at least one radial bearing surface of an oblong hole capable of cooperating with support pins (13, 14) of the housing (1), at least one of the sides (17, 18) including means (23) for the circumferential positioning of the sector (2) with respect to the housing (1), wherein each radial bearing surface is cylindrical relative to axis X and is capable of bearing on a complementary cylindrical surface relative to axis X of a support pin.

Abstract: A process for depositing a coating on short fibres of carbon or silicon carbide from a coating precursor, the short fibres having a length of between 50 ?m and 5 mm, the process including at least heating the short fibres by placing a mixture including the fibres and a liquid phase of the coating precursor in a microwave field so as to bring the surface of the fibres to a temperature allowing the coating on the fibres from the coating precursor to be formed by calefaction.

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 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 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 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.