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: A method of regulating a high temperature gas phase process on the basis of a measurement curve determined by means of infrared spectroscopy, the curve having at least one spectral peak which is characteristic for the regulation of the process and which deviates from a background of the measurement curve. A straight line synthetic background is calculated directly from the measurement curve on the basis of initial and end values of the characteristic spectral peak, and the peak is integrated over the straight line, or a maximum height of the peak over the straight line, or another characteristic value of the peak relative to the straight line is utilized. The process is regulated based on measured peak and the synthetic background.

Abstract: An installation for densification of porous substrates by CVI comprises an oven, a zone for loading substrates in the oven, means for heating substrates loaded in the loading zone, at least one inlet for admitting reactive gas in the oven, and at least one gas heating zone situated in the oven between the reactive gas inlet and the loading zone. At least one gas preheating device is located outside the oven and is connected to the gas inlet so as to preheat the reactive gas before it enters the oven.

Abstract: A new type of silica-modified membrane has been developed by the high-temperature, atmospheric-pressure CVD of Vycor glass. The new membrane, Nanosil, showed unprecedented selectivity to hydrogen (100%), without loss of permeability compared to the porous Vycor precursor. The membrane also showed high stability under hydrothermal conditions over prolonged time. The suitability of a Rh/Al2O3 catalyst for the methane reforming with carbon dioxide was also demonstrated. The limitations imposed by thermodynamics on methane conversion have been circumvented by the use of membranes to preferentially remove hydrogen during reaction. The shortcoming of the Knudsen mode of diffusion was overcome by the development of the modified porous glass membrane.

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: This invention relates to processes for the assembly of three-dimensional structures having periodicities on the scale of optical wavelengths, and at both smaller and larger dimensions, as well as compositions and applications therefore. Invention embodiments involve the self assembly of three-dimensionally periodic arrays of spherical particles, the processing of these arrays so that both infiltration and extraction processes can occur, one or more infiltration steps for these periodic arrays, and, in some instances, extraction steps. The product articles are three-dimensionally periodic on a scale where conventional processing methods cannot be used.

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 porous perform body is infiltrated with carbon by a thermal gradient process using a multi-portion heating element to heat the body. Selected portions of the heating element are supplied with power to create the thermal gradient between different areas of the preform body.

Abstract: A process is disclosed for producing a high temperature stable fiber composite ceramic by chemical vapor infiltration (CVI) with a silicon carbide precursor in a suitable carrier gas on carbon fiber preforms or silicon carbide fiber preforms. This process is characterized by the use of a process pressure of ≧0.6 bar absolute and a process temperature of ≧1100° C. Also disclosed are structural component parts, particularly for aircraft and spacecraft engineering, which are commonly exposed to high thermal and mechanical loading and which have been produced by the above process.

Abstract: A porous preform body is infiltrated with carbon by a thermal gradient process using a multi-portion heating element to heat the body. Selected portions of the heating element are supplied with power to create the thermal gradient between different areas of the preform body.

Abstract: A method for preparing thin films of noble metals upon porous substrate surfaces including utilizing plasma polymerization wherein the noble metals are derived from a monomer or comonomer precursor of the noble metal and with the precursor being disposed within a plasma glow zone to convert the precursor to its dissociated form, thereby allowing the substrate to receive a deposit of a substantially continuous noble metal film thereon. A wide variety of noble metals and their alloys may be treated in this fashion, including such noble metals as platinum, ruthenium, gold and certain alloys thereof.

Abstract: There is provided a method of manufacturing a carbon nanotube so as to be able to increase the yield of a web and to increase the amount of a carbon nanotube contained in the web. A high-energy heat source is caused to act on carbon in the presence of catalysts. The catalysts include a main catalyst made of at least one metal which is selected from the group consisting of an iron group element, a platinum group element, and a rare earth element, and an auxiliary catalyst made of a material which causes an exothermic reaction in a process of generating the web including the carbon nanotube. The auxiliary catalyst is made of a material for generating a carbide more stable in terms of thermal energy than a carbide generated by the main catalyst. The free formation energy of the carbide generated from the material is smaller than the free formation energy of the carbide generated by the main catalyst.

Abstract: A method of deposing a carbon-containing substance in the pores of a porous body comprises establishing an open varying magnetic field flux loop and placing the body such that a magnetic field flux generated by the open magnetic field flux loop passes through a region of said body and heats that region, creating a thermal gradient across the body and bringing a thermally decomposable carbon-containing gas into contact with the heated region, thereby depositing a carbon-containing substance in the pores if said heated region.

Abstract: The present invention provides a method of densifying porous structures by chemical vapor infiltration. In characteristic manner, said densification method is implemented using toluene as a precursor for carbon. Said toluene is generally used mixed with at least one carrier gas.

Abstract: A method for surface modification of 3-dimensional bulk polymers is provided to improve surface properties and surface conductivity of 3-dimensional bulk polymers by using plasma source ion implantation technique. The plasma source ion implantation technique is to modify the surface by implanting ions into the surface of the 3-dimensional samples uniformly. When negative high voltage pulse is applied to a metallic grid around the bulk polymer samples, ions are extracted from the plasma; most of ions passing the grid and collide with the surface of the bulk polymer samples in high energy. Therefore, through the method for applying high voltage pulse to the grid around samples, ions are implanted into the surface of the 3-dimensional bulk polymer samples uniformly, and thereby the ions implanted in high energy modify the bulk polymer surface to improve the electrical conductivity effectively.

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: At least one layer of fibers of a material susceptible to heating by electromagnetic radiation is incorporated in a porous structure. The structure is subjected to the radiation to heat up the body which is contacted with hydrocarbon gas to cause the gas to deposit carbon within the porous structure and thereby cause densification.

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: The invention relates to the field of high temperature composites made by the chemical vapor infiltration and deposition of a binding matrix within a porous structure. More particularly, the invention relates to pressure gradient processes for forcing infiltration of a reactant gas into a porous structure, apparatus for carrying out those processes, and the resulting products. The invention is particularly suited for the simultaneous CVI/CVD processing of large quantities (hundreds) of aircraft brake disks.

Abstract: A laminated matrix composite made of a reinforcement phase and coated with several layers of a metallic, ceramic, or polymeric matrix material, the average thickness of the layers of matrix material being between 0.005 and 5 &mgr;m thick.

Abstract: This invention relates to processes for the assembly of three-dimensional structures having periodicities on the scale of optical wavelengths, and at both smaller and larger dimensions, as well as compositions and applications therefore. Invention embodiments involve the self assembly of three-dimensionally periodic arrays of spherical particles, the processing of these arrays so that both infiltration and extraction processes can occur, one or more infiltration steps for these periodic arrays, and, in some instances, extraction steps. The product articles are three-dimensionally periodic on a scale where conventional processing methods cannot be used.

Abstract: A method of depositing a carbon-containing substance in the pores of a porous body comprises establishing an open varying magnetic field flux loop and placing the body such that a magnetic field flux generated by the open magnetic field flux loop passes through a region of said body and heats that region, creating a thermal gradient across the body and bringing a thermally decomposable carbon-containing gas into contact with the heated region, thereby depositing a carbon-containing substance in the pores of said heated region.

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 method for the densification of a porous structure comprises providing the structure with a body of material (13, 14) which includes a susceptor element foil (14) which is more susceptible to heating by electromagnetic radiation than the other material (13) of the body, exposing said porous structure to hydrocarbon gas and simultaneously applying an electromagnetic field to said porous structure whereby said susceptor element (14) at least in part causes heating of the porous structure to a temperature at which the gas infiltrating the porous structure deposits carbon within the porous structure.

Abstract: A method for the densification of an annular body having a porous structure and comprising layers of fabric, which includes locating a susceptor element within the porous body, the amount of the susceptor element occupying less than 5% of the volume of the porous body, the susceptor element being in the form of a layer comprising one of a foil and a fiber and having plural holes therein through which adjacent layers of fabric of the porous body contact each other, said susceptor element being made of a material which is more susceptible to heating by electromagnetic radiation than the material of the porous body, and exposing the porous body to hydrocarbon gas and simultaneously applying an electromagnetic field to the porous body, the susceptor element within the porous body at least in part causing heating of the porous body to a temperature at which the gas infiltrating the porous body deposits carbon within the porous body.

Abstract: A coating is applied to reinforcing fibers arranged into a tow by coaxially aligning the tow with an adjacent separation layer and winding or wrapping the tow and separation layer onto a support structure in an interleaved manner so that the separation layer separates a wrap of the tow from an adjacent wrap of the tow. A coating can then be uniformly applied to the reinforcing fibers without defects caused by fiber tow to fiber tow contact. The separation layer can be a carbon fiber veil.