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 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 and a device for infiltration of a structure made of a porous material by chemical vapor deposition. According to the method, a first face of the porous material structure is exposed to a gaseous flow, and the second face is maintained at least partially free from any contact.

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 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 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: A method of chemical vapor infiltration and deposition includes stacking a number of porous structures in a stack in a furnace. The stack has a center opening region extending through the porous structures and an outer region extending along the porous structures. A first portion of a reactant gas is introduced to the center opening region. A second portion of the reactant gas is introduced to the outer region. The first portion and the second portion are controlled proportions thereby introducing predetermined portions of the reactant gas to both the center opening region and the outer region. The change in weight of the entire furnace, including contents, is measured during the chemical vapor infiltration and deposition process. The rate of weight change is monitored.

Abstract: Carbon-ceramic brake discs, the remaining porosity in which, after infiltration with a carbide-forming element and reaction of this element with at least part of the carbon in the preliminary body of the carbon-ceramic brake disc to form carbides, is at least partly filled with particles whose average diameter is in the range from 0.5 nm to 20 nm, and a process for producing carbon-ceramic brake discs with reduced porosity, wherein carbon-ceramic brake discs are treated with a solution of organic compounds of boron, zirconium, titanium, silicon or aluminum or mixtures of such compounds, the cited organic compounds being present as sols in an organic solvent, after removal from the sol bath the brake discs treated in this way are dried in an oven at a heating rate of between 30 K/h and 300 K/h under air or protective gas and are then tempered at a final temperature of between 350° C. and 800° C.

Abstract: An apparatus and method for densifying porous structures inside a furnace using pressure gradient CVI/CVD. The apparatus includes a stack of porous structures where each porous structure has an aperture therethrough. The apparatus also includes at least one ring-like spacer disposed within the stack of porous structures between neighboring porous structures. The ring-like spacer encircles the apertures of the neighboring porous structures. The stack of porous structures and the at least one ring-like spacer define an enclosed cavity including each porous structure aperture. A channel provides fluid communication between the enclosed cavity and an outer volume defined by the interior surface of the furnace.

Abstract: Method for densifying a porous carbon preform (5). The method includes the steps of: (a) providing the apparatus (11); (b) charging the apparatus (11) with a plurality of stacks of annular porous carbon preforms (5), the preforms being separated from one another by spacers (15); (c) locating the charged apparatus (11) in a furnace at a temperature in the range of 950-1100° C. and a pressure in the range of 5-40 torr; and (d) circulating a natural gas reactant blended with up to 15% propane through the apparatus for a period of from 150 to 900 hours. Carbon-carbon composite preforms made by this method may be configured as aircraft landing system brake discs or racing car brake discs.

Abstract: A method for densification of porous by CVI in which substrates are loaded into a loading zone of an oven and heated to a temperature at which a desired matrix material is formed from a precursor gas(es). A reative gas containing the precursor gas(es) is admitted into the end of the oven and heated upstream from the loading zone of the substrates. The reactive gas is also preheated prior to entering the oven so that, upon entering the oven, it is brought to an intermediate temperature between ambient temperature and the temperature to which the substrates are heated. In this manner, a very small temperature gradient is obtained throughout the loading zone.

Abstract: A porous substrate having a concave inside face and an outside face is disposed in an enclosure, and reactive gas is introduced into the enclosure to densify the substrate. At least a portion of the gas is divided into two non-zero fractions. The first fraction of the gas is fed to the inside face of the substrate. The second fraction of the gas is fed to only the outside face of the substrate. Alternatively, the first fraction of the gas is fed via a tooling extending into an inside volume defined by the concave inside face of the substrate.

Abstract: A method and apparatus for a continuous coating of a part may include providing a separation layer made of a material that is weaker than the material of the coating to be made. The part may be placed on one or more supports, the supports coated with the separation layer. A continuity layer of a component material of the coating to be made is interposed between the part and the or each support, at least in vicinity of the or each support zone. The coating is formed by chemical vapor infiltration or deposition, and the part is then separated from the or each support by rupture within the separation layer, the continuity of the coating of the part in the or each support zone being provided by the portion of the coating that comes from the continuity layer that remains in place on the part.

Abstract: The invention relates to pressure gradient processes for forcing infiltration of a reactant gas into a porous structure. The process comprises the steps of partially densifying a porous structure with a pressure gradient CVI/CVD process in which a first potion of the porous structure is subjected to greater pressure than a second portion of the porous structure. The process is suited for the simultaneous CVI/CVD processing of large quantities of aircraft brake.

Abstract: A method for fabricating a CMC (Ceramic Matrix Composite) article, comprising: performing a CVI (Chemical Vapor Infiltration) treatment for forming a SiC matrix layer on the surface of a woven fabric; performing a machining process, after the CVI treatment, for machining the woven fabric; and performing a PIP (Polymer Impregnation and Pyrolysis) treatment, after the machining process, for impregnating an organic silicon polymer as a base material into voids in the matrix layer and pyrolyzing the organic silicon polymer. By this method, the throughput of CMC articles can be preferably increased. The throughput may be further increased by performing a slurry impregnation treatment before or after the PIP treatment, in which slurried SiC is impregnated into the voids in the matrix layer.

Abstract: A part (10) on which a continuous coating is to be formed is put into place on one or more supports provided with a separation layer (26) made of a material that is weaker than the material of the coating to be made. A continuity layer (24) of a component material of the coating to be made is interposed between the part and the or each support, at least in vicinity of the or each support zone. The coating (12) is formed by chemical vapor infiltration or deposition, and the part is then separated from the or each support by rupture within the separation layer (26), the continuity of the coating of the part in the or each support zone being provided by the portion of the coating that comes from the continuity layer (24) that remains in place on the part.

Abstract: A hardware assembly is provided for controlling a first portion of gas and a second portion of gas in a furnace. The first portion of the gas is introduced to a center opening region of a stack of porous structures. The second portion of the gas is introduced to an outer region of the stack of porous structures. Most of the gas flows out of the hardware assembly from either the center opening region or the outer region while some of the gas flows out through small holes from the other region. A densification method is also provided with two densification processes in which the gas flows in opposite directions in the two densification processes.

Abstract: Method of treating a surface of a steam line plug grip wherein the surface is subjected to chemical vapor deposition (CVD) treatment to introduce a hard oxide material into pores and cracks in the surface.

Abstract: A manufacturing method of a fiber reinforced composite member includes the steps of: forming a fabric 1 on the surface of a mandrel 10, infiltrating the formed fabric with matrix, and leaving portions 12a, 12b of the mandrel as integral with the fabric and removing the mandrel before the fabric adheres to the mandrel by matrix infiltration. Subsequently, a remaining portion of the mandrel is used as a reference surface and machining is performed. Without possibility of adhesion to the mandrel and resulting breakage, machining bases (axial center and reference surface) during machining can accurately be provided, and this can largely enhance machining precision and yield of the final product.

Abstract: Methods for coating a substrate and methods of shaping a workpiece comprise formation and use, respectively, of a surface or substrate comprising a first phase selected from nitrides, carbides. carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides, and a second phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides, wherein said second phase comprises a multiplicity of discrete portions positioned into the first phase, with these multiplicity of portions comprising a continuous second phase, and made thereof, coating and articles, especially machining, cutting and shaping tools, wearparts, and methods of making and using the composition, coating and articles.

Abstract: An apparatus to determine the pressure within the furnace during thermal gradient forced flow processes as well as other CVI/CVD processes is disclosed. Further, a method to measure the pressure is also described.

Abstract: A matrix formation process 10 is configured with CVI process 12 and PIP process 14, 15, 16 in which a co-polymer containing at least polycarboxysilane (PCS) and polymethylsilane (PMS) is applied. Crosslinking of each polymer is performed at an intermediate temperature which is lower than the pyrolysis temperature of the polymeres. Polymer impregnation process 15 for infiltrating the co-polymer into a matrix, and inert gas firing process 16 for firing the material at a high temperature in an inert gas atmosphere. In the crosslink process, the mixed polymer is held at about 573K to 723K for a predetermined time. The conversion ratio of the co-polymer crosslinked into SiC in the subsequent firing process is increased, efficiency of filling SiC in the PIP process is increased, and an airtight ceramic-based composite material can be manufactured efficiently within a short time.

Abstract: Improved articles of manufacture are disclosed, together with methods for preparing such articles, whereby the surface of a graphite or comparable substrate is first densified with carbon to reduce surface porosity while still retaining sufficient surface texture to enhance the adherence of a subsequently applied boron coating.

Abstract: A method for isothermic, isobaric chemical vapor infiltration (CVI) of refractory substances, especially of carbon (C) and silicon carbide (SiC), based on diffusion in a porous structure, whereby the pressure of the gas or partial pressure of an educt gas contained in the gas and the dwell time of the gas in the reaction zone are set at a given temperature in the reaction zone so that a deposition reaction occurs in the porous structure in the area of pressure or partial pressure of the saturation adsorption of the gaseous compounds forming the solid phase, saturation adsorption meaning that the deposition speed remains substantially constant at increased pressure of the gas or partial pressure of the educt gas. The reaction of the educt gas is limited in such a way that no more than 50% of the elements in the educt gas as it flows through the reaction zone are deposited as a solid phase in the porous structure.

Abstract: A preferred embodiment of a method for coating a substrate with a chemical compound uses a precursor liquid. This precursor liquid preferably serves as a reagent in the coating process and is housed in a reactor. Once the precursor liquid is placed in the reactor, the substrate is immersed in the precursor liquid. While the substrate is immersed in the precursor liquid, which may or may not contain solid particles, the liquid is fluidized by one or more possible methods: passing a gas through the liquid; recirculating the liquid; and stirring the liquid. In the preferred embodiment, inductive heating of the substrate is performed by an induction coil. The induction coil will be driven by a generator to emit a high frequency alternating current electromagnetic field such that only the substrate is directly heated. Heating the substrate in a fluidized bed will cause chemical vapor deposition or chemical vapor infiltration to occur and the desired chemical compound, or element, to be deposited on the substrate.

Abstract: In pumps for viscous substances, particularly pumps for concrete, with two feed cylinders (2) opening out into a hopper (1), which cylinders (2) alternately draw the material to be forwarded from the hopper (1) and press it via a swingable S-shaped tube (5), arranged within the hopper (1), into a delivery pipe, the swivel bearing is constructed in such a way that the pressure of the material to be forwarded is changed into an axial thrust force on the axially movably arranged swivel tube (5) whereby the contact pressure of a wear ring (20) is increased, to ensure a sealing abutment of the wear ring attached to the end of the swivel tube with the rear wall (44) of the hopper (1) including the outlets of the feed cylinders, which wall (44) may if necessary, be reinforced with a spacer (22), and to ensure uniform wear over the whole face of the wear ring (20).