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: In a composite material part having a ceramic matrix and including a fibrous reinforcement which is densified by a matrix consisting of a plurality of ceramic layers having a crack-diverting matrix interphase positioned between two adjacent ceramic matrix layers, the interphase includes a first phase made of a material capable of promoting the diversion of a crack reaching the interphase according to a first propagation mode in the transverse direction through one of the two ceramic matrix layers adjacent to the interphase, such that the propagation of the crack continues according to a second propagation mode along the interphase, and a second phase consisting of discrete contact pads that are distributed within the interphase and capable of promoting the diversion of the crack that propagates along the interphase according to the second propagation mode, such that the propagation of the crack is diverted and continues according to the first propagation mode through the other ceramic matrix layer that is adj

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: A method of densifying a porous substrate with pyrolytic carbon includes loading the substrate into an oven, admitting a reaction gas mixture to the oven, extracting an effluent gas from the oven, and recycling components of the effluent gas into the reaction gas mixture. The reaction gas mixture contains a pyrolytic carbon precursor gas together with a vector gas. The effluent gas contains residual components of the reaction gas mixture together with reaction products, including hydrogen. The recycling is performed after eliminating heavy hydrocarbons contained in the effluent gas.

Abstract: An interphase coating is formed by chemical vapor infiltration (CVI) on the fibers constituting a fiber preform, the interphase coating comprising at least an inner layer in contact with the fibers for embrittlement relief to the composite material, and an outer layer for bonding with the ceramic matrix. The fiber preform is then kept in its shape by the fibers provided with the interphase coating and is consolidated by being impregnated with a liquid composition containing a ceramic precursor, and by transforming the precursor into a ceramic matrix consolidation phase. The consolidated preform is then densified by an additional ceramic matrix phase. No support tooling is needed for forming the interphase coating by CVI or for densification after consolidation using the liquid technique.

Abstract: A method of densifying porous substrates by chemical vapor infiltration comprises loading porous substrates for densification in a loading zone of an enclosure (10), heating the internal volume of the enclosure, and introducing a reagent gas into the enclosure though an inlet situated at one end of the enclosure. Before coming into contact with substrates (20) situated in the loading zone, the reagent gas admitted into the enclosure is preheated, at least in part, by passing along a duct (30) connected to the gas inlet and extending through the loading zone, the duct being raised to the temperature inside the enclosure, and the preheated reagent gas is distributed in the loading zone through one or more openings (33) formed in the side wall (32) of the duct, along the duct.

Abstract: The method comprises the steps of: forming a porous fiber-reinforcing structure; introducing into the pores of the fiber structure powders containing elements for constituting the composite material matrix; and forming at least a main fraction of the matrix from said powders by causing a reaction to take place between said powders or between at least a portion of said powders and at least one delivered additional element; the powders introduced into the fiber structure and the delivered additional element(s) comprising elements that form at least one healing discontinuous matrix phase including a boron compound and at least one discontinuous matrix phase including a crack-deflecting compound of lamellar structure. At least a main fraction of the matrix is formed by chemical reaction between the powders introduced into the fiber structure and at least one delivered additional element, or by sintering the powders.

Abstract: A method of sending data via a communications network NTWK interconnecting terminals (T0 Tj TN). The method includes a step of storing information (Int0) at the command of the initiator terminal (T0) in a memory space S(Inf0) which is accessible to non-initiator terminals (T1, . . . , Tj, . . . , TN) only in read mode and a step of sending a non-initiator terminal a solicitation message Sm(1,P,A0,T1,T2) giving the location (A0) of said memory space S(Inf0). This method makes it possible to prevent the formation of loops perpetually circulating out-of-date requests.

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: An interphase coating is formed by chemical vapor infiltration (CVI) on the fibers constituting a fiber preform, the interphase coating comprising at least an inner layer in contact with the fibers for embrittlement relief to the composite material, and an outer layer for bonding with the ceramic matrix. The fiber preform is then kept in its shape by the fibers provided with the interphase coating and is consolidated by being impregnated with a liquid composition containing a ceramic precursor, and by transforming the precursor into a ceramic matrix consolidation phase. The consolidated preform is then densified by an additional ceramic matrix phase. No support tooling is needed for forming the interphase coating by CVI or for densification after consolidation using the liquid technique.

Abstract: One or more porous substrates for densification (10) are loaded into an oven (12) into which there is admitted a reaction gas containing a pyrolytic carbon precursor gas comprising at least one gaseous hydrocarbons CxHy in which x and y are integers and x is such that 1<x<6, together with a vector gas comprising at least one gas selected from methane and inert gases. Effluent gas containing residual components of the admitted gas together with reaction products, including hydrogen, is extracted from the oven and at least a fraction of a gas stream extracted from the effluent gas and containing pyrolytic carbon precursor reagent gas is recycled (circuit 80) into the reaction gas admitted into the oven, the recycling being performed after eliminating heavy hydrocarbons (treatment 40) contained in the effluent gas.

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: A method of densifying porous substrates by chemical vapor infiltration comprises loading porous substrates for densification in a loading zone of an enclosure (10), heating the internal volume of the enclosure, and introducing a reagent gas into the enclosure though an inlet situated at one end of the enclosure. Before coming into contact with substrates (20) situated in the loading zone, the reagent gas admitted into the enclosure is preheated, at least in part, by passing along a duct (30) connected to the gas inlet and extending through the loading zone, the duct being raised to the temperature inside the enclosure, and the preheated reagent gas is distributed in the loading zone through one or more openings (33) formed in the side wall (32) of the duct, along the duct.

Abstract: The material comprises fiber reinforcement made of fibers that are essentially constituted by silicon carbide, and an interphase layer between the fibers of the reinforcement and the matrix. The reinforcing fibers are long fibers containing less than 5% atomic residual oxygen and they have a modulus greater than 250 GPa, and the interphase layer is strongly bonded to the fibers and to the matrix such that the shear breaking strengths within the interphase layer and at the fiber-interphase bonds and at the interphase-matrix bonds are greater than the shear breaking strengths encountered within the matrix.