Abstract: Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, an oxidation protection system disposed on a substrate may comprise a boron-silicon-glass layer formed directly on the composite structure. The boron-silicon-glass layer may comprise a boron compound, a silicon compound, and a glass compound.

Abstract: A high-temperature-steam-oxidation-resistive coated reinforcement fiber applicable to a fiber reinforced composite, is provided with: a reinforcement fiber; a coating layer covering the reinforcement fiber and including a rare-earth silicate; an exfoliative layer intervening in an interface between the coating layer and the reinforcement fiber; and a supplemental coating layer covering the reinforcement fiber, the exfoliative layer and the coating layer.

Abstract: Various embodiments of the present invention are directed towards a system and method relating to depositing vapor in a sample. For example, a device includes a vapor source chamber configured to contain a vapor source material to generate vapor. An activation chamber is configured to contain a sample. The activation chamber is in fluid communication with the vapor source chamber to receive the vapor. A permeable separator divides the vapor source chamber and the activation chamber, and isolates the sample in the activation chamber while allowing vapor to pass between the vapor source chamber and the activation chamber. The device is sealable and configured to apply vacuum to the vapor and sample, to cause deposition of the vapor into the pumice stone samples.

Abstract: Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, an oxidation protection system disposed on a substrate may comprise a boron-silicon-glass layer formed directly on the composite structure. The boron-silicon-glass layer may comprise a boron compound, a silicon compound, and a glass compound.

Abstract: A seal assembly for a gas turbine engine according to an example of the present disclosure includes a seal that has a main body extending circumferentially between opposed mate faces. The main body has a sealing portion and an engagement portion extending outwardly from sealing portion along at least one of the mate faces. The main body has a core that has one or more core plies having a first fiber construction and arranged to establish an internal cavity. An overwrap has one or more overwrap plies having a second fiber construction and arranged to follow a perimeter of the one or more core plies to establish the engagement portion and the sealing portion, and the second fiber construction differs from the first fiber construction. The first fiber construction establishes a first target fiber volume fraction, the second fiber construction establishes a second target fiber volume fraction. A method of fabricating a seal for a gas turbine engine is also disclosed.

Abstract: A method of densifying an annular porous structure comprises stacking a plurality of annular porous structures to form a porous structure stack in a graphite susceptor, wherein the graphite susceptor is disposed within a vessel. The method includes disposing a graphite panel within the graphite susceptor and located radially inward from the porous structure stack. The method includes flowing a reactant gas into the vessel.

Abstract: A composite material part includes a fiber preform forming fiber reinforcement including a stack of at least two fiber plies, each of the fiber plies being made of an interlock weave three-dimensional fabric and each of the fiber plies having a number of warp yarn layers or a number of weft yarn layers that is greater than or equal to three; and a matrix present in the pores of the fiber preform.

Abstract: The present invention concerns a shaped composite material and a method for producing it. More specifically, the invention concerns a disc for a disc brake made from ceramic composite materials, usually known as “CMC”, i.e. “Carbon Material Ceramic” or “CCM”, i.e. “Carbon Ceramic Material”. These materials consist of carbon matrices containing carbon fibres usually infiltrated with silicon and a product of reaction between C and Si, silicon carbide (SiC). More specifically, the invention concerns a shaped composite material comprising a inner layer (3; 103) of CCM C/SiC/Si material comprising disorderly short filaments consisting mainly of carbon and respective outer layers (2, 2?; 102, 102?) of C/SiC/Si material and having an orderly fabric structure of mainly carbon fibres.

Abstract: An enclosed-channel reactor system is provided, which includes: a reactor body having a plurality of enclosed channels therein; an upper cap disposed at one end of the reactor body and having an inlet port communicating with the plurality of enclosed channels; a lower cap disposed at the other end of the reactor body opposite to the upper cap and having an outlet port communicating with the plurality of enclosed channels; and at least a conduit plate disposed between the upper cap and the reactor body for guiding a precursor injected from the inlet port into the plurality of enclosed channels uniformly.

Abstract: A process and an apparatus for densifying a porous structure is disclosed. The porous structure comprises a first surface, a second surface, an inner diameter surface and an outer diameter surface. The process may comprise progressive densification in conjunction with thermal gradient and/or pressure gradient densification processes.

Abstract: An installation for chemical vapor infiltration of porous preforms of three-dimensional shape extending mainly in a longitudinal direction, the installation comprising a reaction chamber of parallelepiped shape, the side walls of the reaction chamber including heater means and a plurality of stacks of loader devices arranged in the reaction chamber. Each loader device being in the form of an enclosure of parallelepiped shape provided with support elements for receiving porous preforms for infiltrating.

Abstract: Method for producing shaped bodies from reaction-bonded, silicon-infiltrated silicon carbide and/or boron carbide, characterized in that a monolithic preliminary body is built up in layers using a formless granulation to which a physical or chemical hardening or melt process is applied, wherein the granulation has a weight fraction of at least 95% silicon carbide and/or boron carbide with an average grain size of 70 to 200 ?m, the so-created preliminary body is impregnated at least once by the introduction of a carbon black suspension or via a gas-phase separation and secondary silicon carbide is created in contact with liquid or gaseous silicon by a subsequent reaction firing that solidifies an engagement composite produced.

Abstract: A ceramic matrix composite blade for use in a gas turbine engine having an airfoil with leading and trailing edges and pressure and suction side surfaces, a blade shank secured to the lower end of each airfoil, one or more interior fluid cavities within the airfoil having inlet flow passages at the lower end which are in fluid communication with the blade shank, one or more passageways in the blade shank corresponding to each one of the interior fluid cavities and a fluid pump (or compressor) that provides pressurized fluid (nominally cool, dry air) to each one of the interior fluid cavities in each airfoil. The fluid (e.g., air) is sufficient in pressure and volume to maintain a minimum fluid flow to each of the interior fluid cavities in the event of a breach due to foreign object damage.

Abstract: A method for producing a part made of ceramic matrix and ceramic fibers composite material. It comprises: the formation of a fibrous preform by intertwining threads constituted of ceramic material fibers on a contact surface of a support element reproducing the internal and/or external shape of the part to be produced; the partial densification of the fibrous preform at a temperature below the melting temperature of the material of the support element and below the melting temperature of the material of the fibers of the preform, said partial densification resulting in a consolidated fibrous preform comprising a matrix volume fraction above 5% and at the most equal to 40% of the matrix volume of the part to be produced; the removal of the support element from the consolidated fibrous preform by chemical attack of the contact surface of the material of the support element; the densification of the consolidated preform, carried out at a temperature below the melting temperature of the fibers of said preform.

Abstract: In one example, a method comprises densifiying a carbonized preform via at least one of resin transfer molding (RTM), vacuum pitch infiltration (VPI) and chemical vapor infiltration/chemical vapor deposition (CVI/CVD), heat treating the densified preform to open internal pores of the densified preform, and infiltrating the internal pores of the densified preform with low viscosity resin to increase the density of the preform.

Abstract: Carbon-carbon composites made by needling together woven or nonwoven fabric made from carbon-containing fibers followed by carbonizing the fabric preforms are described. The carbon fiber preforms can be needled either in a carbonized or in an uncarbonized state. The uncarbonized fiber preforms would go through a carbonization/heat-treat step following the needling process. Final preform thickness and fiber volume is also controlled at carbonization, for instance by varying the level of pressure applied to the preforms during carbonization. For example, the preforms may be unconstrained during carbonization (i.e., no pressure is applied to them) or the preforms may be constrained during carbonization, typically by means for applying pressure (e.g., weight placed on top of the preforms).

Abstract: The present invention relates to a method for hydrophobization of a fabric surface comprising providing a stream of a substantially anhydrous gas, passing said gas over or through a substantially anhydrous liquid of an alkylsilane, preferably a fluorinated alkylsilane to provide an alkylsilane, preferably a fluorinated alkylsilane vapor and bringing said vapor in contact with the fabric surface, thereby allowing the optionally fluorinated alkylsilane to bind covalently to the fabric surfaced. The present invention further relates to a fabric comprising a superhydrophobic surface finish prepared by a method of the invention and to a device for carrying out the method of the invention.

Abstract: Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.

Abstract: Method for chemical vapor infiltration of refractory substances, wherein a porous structure is subjected in a reaction zone to the flow of a gas containing at least one gaseous precursor, wherein the partial pressure of the precursor and the dwell time of the gas are set at a given temperature in such a manner that a deposition reaction of the precursor occurs in the porous structure in the partial pressure range of the saturation adsorption and the reaction of the precursor is limited in each stage of the infiltration in such a manner that during the flow through the reaction zone no more than 50% of the precursor are deposited as a solid phase in the porous structure, and the exposure of the porous structure to the flow occurs in a stack of superimposed layers through ring-shaped vertical circumferential gaps (A, B) as well as through transverse gaps (C) which are open towards the circumferential gaps (A, B).

Abstract: A method of depositing a conformal coating on a porous non-ceramic substrate requires reactive gases to flow through the substrate so as to leave a conformal coating behind. The process can be used to leave a hydrophilic surface on the interior pores of the substrate, even when the substrate is of a naturally hydrophobic, e.g., olefinic material. The method can be used in a roll-to-roll process, or in a batch process. In some convenient embodiments of the latter case, the batch reactor and the conformally coated substrate or substrates can together go on to be come part of the end product, e.g., a filter body and the filter elements respectively.

Abstract: A method of fabricating a complex part out of composite material including three-dimensional woven fiber reinforcement densified by a matrix, the method including three-dimensionally weaving a continuous fiber strip including a succession of fiber blanks for preforms of a plurality of parts that are to be fabricated; subsequently cutting individual fiber blanks out from the strip, each blank being a one-piece blank; shaping a cut-out blank to obtain a one-piece fiber preform having a shape that is close to the shape of a part that is to be fabricated; consolidating the preform in the desired shape; and densifying the consolidated preform by forming a matrix by chemical vapor infiltration.

Abstract: The invention relates to a method for coating, by means of a chemical vapour deposition (CVD) technique, a part with a coating (PAO) for protecting against oxidation. The method enables the preparation of a refractory coating for protecting against oxidation, having a three-dimensional microstructure, which ensures the protection against oxidation at a high temperature, generally at a temperature above 1200° C., for materials that are sensitive to oxidation, such as composite materials, and in particular carbon/carbon composite materials.

Abstract: A process for the production of pyrolytic carbon comprising the steps of: (A) depositing pyrolytic carbon on a substrate, and (B) controlling the structure of the deposited pyrolytic carbon through use of a Volmer-Weber island growth model.

Abstract: A method of fabricating a ceramic component includes using vapor infiltration to deposit a ceramic coating within pores of a porous structure to form a preform body with residual interconnected porosity. Transfer molding is then used to deposit a heated, liquid glass or glass/ceramic material into the residual interconnected porosity. The liquid ceramic or ceramic/glass material is then solidified to form a ceramic component.

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: 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: 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: A method of fabricating a composite material part having carbon fiber reinforcement densified by a matrix, including making a coherent fiber preform of carbon fibers presenting holes formed from at least a first face of the preform, and densifying the preform by depositing therein a material constituting a matrix by means of a chemical vapor infiltration type process. The holes are formed by causing a plurality of non-rotary elongate tools to penetrate simultaneously, the tools being substantially mutually parallel and presenting on their surfaces roughnesses or portions in relief suitable for breaking and/or transferring fibers they encounter, the tools being caused to penetrate simultaneously by moving a support carrying the tools, and the tools being selected to have a cross-section that makes it possible to obtain in the carbon fiber preform holes that present a cross-section with a mean dimension lying in the range 50 ?m to 500 ?m.

Abstract: A friction material is provided for a friction member of a torque-transmitting mechanism. The friction member has a woven carbon fiber fabric base. A coating is applied to the base to form a portion of a contact surface positioned to contact a reaction member during engagement of the torque-transmitting mechanism. The coating is a mixture of a resin binder and a friction modifier. A method of forming a friction material is also provided.

Abstract: A method of producing a densified SiC article is provided. Near-net shape porous silicon carbide articles are produced and densified using the developed method. A substantial number of pores within the porous near-net shape silicon carbide article are filled (impregnated) with a carbon precursor, a silicon carbide precursor, or a mixture of both. The carbon precursor can be liquid or gas. The filled SiC preform is heated to convert the carbon or silicon carbide precursor to porous carbon or SiC preform inside the pores of the net-shape silicon carbide article. The impregnation/pyrolysis cycle is repeated until the desired amount of carbon and/or silicon carbide is achieved. In case of a carbon or a mixture of silicon carbide/carbon precursor is used, the pyrolyzed near-net shape silicon carbide article is then contacted with silicon in an inert atmosphere.

Abstract: The present invention describes a method of CVI densification in which particular arrangements and mixtures of undensified porous substrates and partially densified porous substrates are arranged in particular ways in order to use the thermal characteristics of the partially densified porous substrates to better distribute heat throughout a CVI furnace and thereby improve densification.

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: A method of fabricating a complex part out of composite material including three-dimensional woven fiber reinforcement densified by a matrix, the method including three-dimensionally weaving a continuous fiber strip including a succession of fiber blanks for preforms of a plurality of parts that are to be fabricated; subsequently cutting individual fiber blanks out from the strip, each blank being a one-piece blank; shaping a cut-out blank to obtain a one-piece fiber preform having a shape that is close to the shape of a part that is to be fabricated; consolidating the preform in the desired shape; and densifying the consolidated preform by forming a matrix by chemical vapor infiltration.

Abstract: A process for densifying porous structures inside a furnace using non-pressure gradient CVI/CVD includes disposing a number of porous structures in a stack within a furnace. The stack has a center opening region extending through the porous structures and an outer region extending along the outside of the porous structures. Channels provide fluid communication between the center opening region and the outer region. A first portion of a gas composition is introduced to the center opening region. A second portion of the gas composition is introduced to the outer region. The porous structures are densified from an average density of less than 0.60 g/cm3 to an average density of greater than 1.70 g/cm3 in a single cycle of non-pressure gradient CVI/CVD.

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 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 process for making nanostructures on a support, including: supplying a support including a surface layer on one of its faces, covering the surface layer by a catalyst layer structured according to a pattern exposing areas of the surface layer covered by the catalyst and areas of the surface layer not covered by the catalyst, etching the thickness of the surface layer in the areas not covered by the catalyst layer, and selectively growing nanostructures on the areas of the surface layer covered by the catalyst. The process can also be used to make cathode structures with electrically independent nanostructures.

Abstract: Method of chemical vapor infiltration of a deposable carbon material into a porous carbon fiber preform in order to densify the carbon fiber preform. The method includes the steps of: situating the porous carbon fiber preform in the reaction zone; providing a linear flow of a reactant gas comprising deposable carbon material in the reaction zone at an initial reaction pressure of at most 50 torr to produce deposition of the deposable carbon material into the preform; and adjusting the pressure of the gas to reaction pressures lower than said initial reaction pressure while deposable carbon material continues to be deposited into the porous carbon fiber preform. This method enables attainment of a target increased density in a carbon fiber preform much more quickly than known processes. A programmed pressure swing throughout the CVI/CVD run may be set in order to provide a linear increase in density.

Abstract: Economically attractive method of making carbon-carbon composite brake disc or pad. The manufacturing method herein provides lowered manufacturing cycle time and reduced cost of manufacturing while enabling increased density of the final composite. The method includes: providing a fibrous nonwoven fabric segment produced from high basis weight fabric; optionally needling sequential layers of the fabric segments together to construct a brake disc or pad preform; carbonizing the fibrous preform to obtain a carbon-carbon preform; and infiltrating the resulting carbonized needled fibrous fabric preform via pitch or pitch and CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad which has a final density of 1.60 to 1.90 grams per cubic centimeter.

Abstract: A carrier for an object, preferably a substrate of a semiconductor component such as a wafer, includes a receiving element for the object and gas outlets arranged below the receiving element along the object received. At least sections of the carrier are made of a material which including stabilizing fibers and having a porosity which forms the gas outlets, in order to enable a desired gas to exit from the gas outlets in a dosed and finely distributed manner.

Abstract: A ceramic matrix composite is formed from a non-oxide ceramic and continuous ceramic fibers. The matrix includes a hafnium donor in the matrix in an amount sufficient to harden the composite at elevated temperatures to prevent ablation of the composite. The matrix also includes a boron donor in the matrix in an amount sufficient to lower the glass transition temperature of the composite to flow over cracks formed in the composite. The method to form the matrix is selected from polymer infiltration pyrolysis, chemical vapor infiltration, and sequential polymer infiltration pyrolysis and chemical vapor infiltration.

Abstract: A method of producing a densified SiC article is provided. Near-net shape porous silicon carbide articles are produced and densified using the developed method. A substantial number of pores within the porous near-net shape silicon carbide article are filled (impregnated) with a carbon precursor, a silicon carbide precursor, or a mixture of both. The carbon precursor can be liquid or gas. The filled SiC preform is heated to convert the carbon or silicon carbide precursor to porous carbon or SiC preform inside the pores of the net-shape silicon carbide article. The impregnation/pyrolysis cycle is repeated until the desired amount of carbon and/or silicon carbide is achieved. In case of a carbon or a mixture of silicon carbide/carbon precursor is used, the pyrolyzed near-net shape silicon carbide article is then contacted with silicon in an inert atmosphere.

Abstract: Method of making carbon-carbon composite brake disc or pad. The manufacturing method herein benefits from lowered manufacturing cycle time, reduced cost of manufacturing, and at the same time increased density of the final composite. The method includes: providing a fibrous nonwoven fabric segment comprised of OPAN fibers, the segment being produced from high basis weight fabric; providing a needler to needle layers of the fabric segments to one another; needling two layers of the fabric segments to one another and then needling sequential layers of the fabric segments on top of the layers thereof which have previously been needled together, to construct a brake disc or pad preform; carbonizing the fibrous preform to obtain a carbon-carbon preform; and infiltrating the resulting carbonized needled fibrous fabric preform via CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad which has a density of at least 1.70 grams per cubic centimeter.

Abstract: Methods for generating and applying coatings to filters with porous material in order to reduce large pressure drop increases as material accumulates in a filter, as well as the filter exhibiting reduced and/or more uniform pressure drop. The filter can be a diesel particulate trap for removing particulate matter such as soot from the exhaust of a diesel engine. Porous material such as ash is loaded on the surface of the substrate or filter walls, such as by coating, depositing, distributing or layering the porous material along the channel walls of the filter in an amount effective for minimizing or preventing depth filtration during use of the filter. Efficient filtration at acceptable flow rates is achieved.

Abstract: A method of producing a densified SiC article is provided. Near-net shape porous silicon carbide articles are produced and densified using the developed method. A substantial number of pores within the porous near-net shape silicon carbide article are filled (impregnated) with a carbon precursor, a silicon carbide precursor, or a mixture of both. The carbon precursor can be liquid or gas. The filled SiC preform is heated to convert the carbon or silicon carbide precursor to porous carbon or SiC preform inside the pores of the net-shape silicon carbide article. The impregnation/pyrolysis cycle is repeated until the desired amount of carbon and/or silicon carbide is achieved. In case of a carbon or a mixture of silicon carbide/carbon precursor is used, the pyrolyzed near-net shape silicon carbide article is then contacted with silicon in an inert atmosphere.

Abstract: An integrally woven three-dimensional preform with stiffeners in two or more directions constructed from a woven fabric having a first, second and optional third woven fabric layer. A plurality of yarns are interwoven over a region between the first and second fabric layers such that the first fabric layer is foldable relative to the second fabric layer. An additional plurality of yarns are interwoven over a region between the second and third fabric layers such that the third fabric layer is foldable relative to the second fabric layer. Upon folding of the woven fabric layers, the integrally woven three-dimensional preform with stiffeners in two or more directions is formed.

Abstract: A load comprising one or more porous substrates (10) for densification is heated in an oven into which a reaction gas containing at least one carbon-precursor hydrocarbon is admitted, the effluent gas being extracted from the oven via an extraction pipe (26) connected to an outlet from the oven. The content in the effluent gas of at least one compound selected from allene, propine, and benzene is measured, and as a function of the measured content, the process is controlled by adjusting at least one parameter selected from the rate at which the reaction gas is admitted into the oven, the rate at least one component of the reaction gas is admitted into the oven, the transit time of the gas through the oven, the temperature to which the substrate(s) is/are heated, and the pressure that exists inside the oven. The at least one parameter is adjusted in such a manner as to maintain the measured content at a value which is substantially constant.

Abstract: A method for densifying porous structures inside a furnace using non-pressure gradient CVI/CVD in a single cycle is described. A hardware assembly for use in the single cycle non-pressure gradient CVI/CVD process is provided as well are process and process conditions are described.

Abstract: A method for forming interphase layers in ceramic matrix composites. The method forms interphase layers in ceramic matrix composites thereby enabling higher matrix densities to be achieved without sacrificing crack deflection and/or toughness. The methods of the present invention involve the use fugitive material-coated fibers. These fibers are then infiltrated with a ceramic matrix slurry. Then, the fugitive material is removed and the resulting material is reinfiltrated with an interphase layer material. The ceramic matrix composite is then fired. Additional steps may be included to densify the ceramic matrix or to increase the strength of the interphase layer. The method is useful for the formation of three dimensional fiber-reinforced ceramic matrix composites envisioned for use in gas turbine components.

Abstract: Methods for manufacturing porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's). Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, a thin coating of nuclear fuel may be deposited inside of a highly porous skeletal structure made, for example, of reticulated vitreous carbon foam.