Abstract: A mandrel for use in a diamond deposition process for generating free standing diamond films has a segmented surface forming a plurality of surfaces for deposition of diamond. The segmented surface is formed of a plurality of mesa segments on a common supporting base surfaces for the mesas. The mesa segments are preferably removably attached to the common base by any suitable means such as by bolts through the mandrel substrate which extend into the mesa segments. The mesa segments may vary in shape, size, and number, thus permitting different shaped diamond films to be made simultaneously from the same run if desired. The provided arrangement increases yield by reducing losses due to premature lifting of the diamond film during deposition, due to violent lifting after deposition upon cooling of the mandrel, and due to cracking.

Abstract: A carbon-carbon composite is provided comprising a preform containing interwoven mats of graphitized vapor grown carbon fibers. The mat comprises semi-aligned, semi-continuous vapor grown carbon fibers which have been interwoven in situ during growth. The preferred method of producing the carbon-carbon composite includes the steps of densifying the preform by depositing pyrolytic carbon into the interstices of the preform by chemical vapor infiltration or pitch infiltration. The resulting carbon-carbon composite has a thermal conductivity of between about 900 W/m-K and 1000 W/m-K and is useful as a component in electronic devices, aircraft, spacecraft, and other thermal management applications.

Abstract: A method and mandrel apparatus for making a unibody containment structure, such as an molecular beam epitaxy cell crucible, with a negative draft portion, via chemical vapor deposition.

Abstract: This invention is directed to a method for shifting the mosaic spread of highly oriented pyrolytic graphite ("HOPG") into a preselected narrow range. The method involves selecting HOPG samples having a mosaic spread which lies below a desired mosaic spread range and cold working the selected samples to form a textured surface sufficent to shift the mosaic spread of the samples into the desired mosaic spread range. The textured surface is preferably imprinted by pressing the samples between metal dies with at least one of the dies having a knurled surface.

Abstract: A single piece, high purity, full density semiconductor wafer holding fixture for holding a multiplicity of wafers and consisting essentially of chemical vapor deposited silicon carbide (CVD SiC). The wafer carrier is advantageous for the fabrication of electronic integrated circuits where high temperatures and/or corrosive chemicals present, where dimensional stability of the holder is advantageous to the process or where introduction of contaminating elements is deleterious to the process. The method for making such an article comprises shaping a substrate, e.g. graphite, which on one surface has the form of the desired shape, said form comprising raised longitudinal sections to support the silicon wafers at the edges of the wafers, chemically vapor depositing a layer of silicon carbide onto the substrate, removing the substrate intact or by burning, machining, grinding, gritblasting and/or dissolving, and grinding the silicon carbide in any areas where a more precise dimension is required.

Abstract: A method of forming a light weight, closed-back mirror. The mirror is formed as a monolithic construction by the use of chemical vapor deposition techniques. A first deposition forms sheets of the material, which are machined to the proper size to form reinforcing ribs. A sacrificial mandrel is formed with grooves to receive the ribs in their assembled positions. The upper surface of the mandrel is in proximity to the rear edges of the ribs to form a substantially continuous surface. The mandrel and ribs are then subjected to a chemical vapor deposition process which forms a first coating upon the outer face of the mandrel, forming a back plate and side wall. The mandrel is then turned over, and the base is removed by machining to expose the front edges of the ribs. This process leaves islands of mandrel material between the ribs to form a substantially continuous surface. The mandrel and ribs are then subjected to a chemical vapor deposition process.

Abstract: In accordance with the present invention a pyrolytic boron nitride compact having an electrical resistivity smaller than about 10.sup.14 .OMEGA.-cm is formed by the process of introducing a feed gas of gaseous boron halide and ammonia at a suitable ratio into a furnace heated to a temperature between 1600.degree. C. to 2200.degree. C. with the furnace containing a substrate of graphite to form a deposit of pyrolytic boron nitride upon said substrate, substantially simultaneously introducing a hydrocarbon gas into the furnace to form a codeposit of carbon in the crystal structure of the pyrolytic boron nitride deposit, controlling the mole fraction of said hydrocarbon gas to limit the concentration of carbon to less than about 3 wt % of the pyrolytic boron nitride composition.

Abstract: Methods for making hermetic silicon carbide matrix composite structures by CVI. A fibrous preform is created by winding strands of yarn of refractory fiber material helically about a graphite mandrel. Impregnation of the preform is carried out in a subatmospheric pressure zone at a pressure of about 700 Pa or less by maintaining a relatively slow flow of a mixture of helium and an alkyl chlorosilane through a coating zone heated to a temperature of between about 1100.degree. to 1200.degree. C. at a rate between about 2 and about 10 times the diffusion rate of the gaseous atmosphere in the fibrous preform. Coating is continued until silicon carbide impregnates the interstices of the fibrous preform and preferably deposits an outer layer of dense pore-free silicon carbide thereupon. The resultant structures are hermetic and provide leak-free containment of gases such as helium at temperatures of as high as 1,000.degree. C. and a pressure differential as high as about 20 MPa.

Abstract: Porous and non-porous compositions include diamond particles, non-diamond particles, or mixtures of particles consolidated with polycrystalline diamond. The composite compositions of the present invention may be formed by a process which includes the steps of preforming the particles into a preform having a desired shape, and consolidating the preform with polycrystalline diamond. The polycrystalline diamond is preferably formed using CVD techniques including application of sufficient microwave energy to maintain the preform at a temperature of between about 670.degree. and 850.degree. C. The preform may be rotated during a portion of the deposition process.

Abstract: A process for joining solid compositions, comprising placing a first solid composition having a first joining zone and a second solid composition having a second joining zone in a chamber; positioning a first gas phase, which comprises a substance that decomposes to a material that adheres to the first and second solid compositions during the process, proximate the target area; directing an energy beam to the first and second joining zones to selectively deposit material from the first gas phase on the first joining zone and the second joining zone until a joint is formed between the first and second solid compositions wherein the joint adheres to the first and second compositions at the first and second joining zones.

Abstract: A process for manufacturing carbonaceous parts including the steps of shaping a mixture of carbonaceous powder and bonding agent to form raw parts, cooling the raw parts to ambient temperature at a known rate and firing the cooled parts in a furnace from ambient temperature to a final firing temperature to release volatile particles to produce fired parts devoid of volatile products. This process is improved by placing the raw parts in an electric furnace in the absence of heating filler, heating the raw parts in the furnace to an intermediate temperature of about 200.degree. C. at a fixed initial heating rate such that the loss of volatile products is less than 10% by weight of the total amount of volatile products contained in the raw parts and being a function of the cooling rate such that the internal strain from the shaping and cooling step is freed.

Abstract: The wafer support apparatus and method provide a plurality of elastic supports having a smooth curvature for contacting a wafer at a respective plurality of support points. Each elastic support directly contacts the wafer at a support point and expands and/or compresses independently of the other elastic supports to accommodate the bending of the wafer during processing.A wafer support apparatus includes a plurality of flexible elastic supports onto which a wafer is directly positioned, wherein each of the plurality of elastic supports holds the wafer during processing by compressing or expanding in response to bending of the wafer during processing to provide continuous even support for the wafer during processing.

Abstract: A method for depositing synthetic diamond includes the following steps: (a) providing a deposition chamber; (b) providing a deposition surface in the deposition chamber, the deposition surface having a concave contour; (c) directing a plasma toward the concave deposition surface, the plasma including hydrogen and a hydrocarbon, such that synthetic diamond is formed on the concave deposition surface; and (d) releasing the synthetic diamond from the concave deposition surface to obtain free standing diamond, wherein the released diamond generally flattens.

Abstract: A thermal shielding element which includes a hollow rigid panel in the form of a shell made of a thermostructural composite including fiber reinforcement densified by a matrix, and a thermal insulant filling the panel is obtained by making a rigid block (20) of thermally insulating material of low density, the block having an outside surface whose shape corresponds to the shape of an inside surface of the panel, a fiber preform (11) constituting the reinforcement of the composite material is formed on the block of insulating material, and the fiber preform is densified with the material that constitutes the matrix of the composite material.

Abstract: Disclosed are a processes and reactors for rapidly producing large diameter, high-purity polycrystalline silicon rods for semiconductor applications by the deposition of silicon from a gas containing a silane compound. The equipment includes a reactor vessel which encloses a powder catcher having a cooled surface. Also within the vessel is a cylindrical water jacket which defines multiple reaction chambers. The silicon powder generated in this process adheres to the coolest surfaces, which are those of the powder catcher, and is thereby collected. Little of the powder adheres to the walls of the reaction chambers. In some embodiments, a fan can be provided to increase gas circulation.

Abstract: A process for manufacturing a transparent conductive film wiring board capable of being practiced according to a dry procedure to simplify the manufacturing and reduce the manufacturing costs. First, a SiO.sub.2 layer is provided on a substrate and then a black ITO film is formed on the SiO.sub.2 layer. The black ITO film is subject to processing using laser emitted from an output horn, resulting in being cut into a predetermined wiring pattern. Metal evaporated by laser processing is sucked by a vacuum suction head. Then, the substrate is subject to calcination to oxidize and crystallize the black ITO film 3 of the wiring pattern to form a transparent ITO film of the wiring pattern.

Abstract: Chemical vapor deposition method for producing a fine grained smooth growth surfaced diamond film on a substrate employs a hydrogen/hydrocarbon gaseous atmosphere containing an amount of nitrogen effective to inhibit the growth of the diamond grains deposited on the substrate.

Abstract: A method for producing free-standing diamond film having a surface area of at least 1000 square millimeters includes the following steps: providing a substrate; depositing, on the substrate, by chemical vapor deposition, a first layer of diamond over a surface area of at least 1000 square millimeters, and to a first thickness, the first layer being deposited at a first deposition rate; depositing, on the first layer, a second layer of diamond, over a surface area of at least 1000 square millimeters, and to a second thickness, the second layer being deposited at a second deposition rate; and releasing the diamond from the substrate; the second deposition rate being as lest twice as high as the first deposition rate, and the first thickness being sufficiently thick to prevent the released diamond from bowing by more than a given distance.

Abstract: A method for growing a diamond film, substantially free of voids, having an average crystallite size greater than about 15 microns, a maximum intensity of the diamond Raman peak in counts/sec divided by the intensity of photoluminescence at 1270 cm.sup.-1 greater than about 3, a Raman sp.sup.3 full width half maximum less than about 6 cm.sup.-1, and a diamond-to-graphite Raman ratio greater than about 25, includes the steps of preparing a substrate by abrasion with diamond particles; placing the substrate in a CVD reactor; depositing diamond during a first deposition stage by providing an atmosphere consisting essentially of a mixture of about 200 sccm H.sub.2 and 10 sccm CH.sub.4, at a pressure of about 90 Torr, providing between about 1,800 and 1,950 watts of microwave power at a frequency of about 2.45 GHz to ignite and sustain a plasma in the region of said substrate, and maintaining the substrate at a temperature of between about 625.degree. C. and 675.degree. C.

Abstract: A fiber preform constituting the fiber reinforcement of the part to be made is itself made by shaping and consolidating a fiber fabric by a liquid process. An interphase layer between the fibers and the matrix is formed on the consolidated preform prior to densification thereof with the matrix, such that the operation of densifying the consolidated preform can be performed without requiring supporting tooling therefor.

Abstract: A method for producing CVD diamond film on a substrate comprised of a hydride-forming metal. The substrate provides for easy release of the CVD diamond coating formed thereon upon exposure to a hydrogen pressure. Self-supporting CVD diamond films of large dimension are easily obtained without dissolving the substrate. The substrate can be used in conventional CVD reactors.

Abstract: Method/apparatus for making a composite wherein reinforcement or filler material, such as, for example, ceramic fibers or whiskers, are confined in a microwave-transparent envelope, the reinforcement or filler material is microwave heated, and a gaseous reactant stream is flowed through the envelope so as to infiltrate interstices of the heated reinforcement or filler material and chemically vapor deposit a matrix, such as a ceramic matrix, from the interior toward the exterior of the heated material. The envelope imparts a desired shape and size to the composite. After infiltration, the envelope typically is removed from the composite.

Abstract: A method and device are provided for reducing the loss of CVD manufactured parts due to cracking caused by mechanical stresses resulting from the mismatch of the coefficient of thermal expansion between the chemical vapor deposed part and the mandrel plate. The method and device provide a removable mandrel support which is removed after the chemical vapor deposition but prior to the cooling of the CVD part and the mandrel plates. This permits the CVD part to contract upon cooling without mechanical restriction, thus reduce cracking caused by contraction of the CVD part against a mold which does not contract substantially.

Abstract: A process for providing extrudable polyacrylonitrile compositions. Dry, particulate polyacrylonitrile having a moisture content of less than about 1.5 percent is mixed with a liquid plasticizer such as ethylene carbonate or propylene carbonate at a mixing temperature of about 140.degree. C. to about 180.degree. C. This process produces an extrudable polyacrylonitrileplasticizer composition which can be extruded to form film, fiber or other extruded or co-extruded products.

Abstract: A method for making a quasi-single crystal diamond is provided. Small diamond granules, like islands, are epitaxially grown on a single crystal substrate having a lattice constant which is similar to that of diamond. A deposition layer is formed on the island diamond granules. The initial substrate is eliminated. Diamond is grown on the deposition layer having diamond granules to make a diamond film having a certain thickness. The initially-grown diamond granules which have the same crystallographical direction align the direction of crystals of the latter-grown diamond by playing a role of seed crystals.

Abstract: A method of producing a plasma treated article in a tool having electrically isolated conductive members, wherein at least one of the members has a surface closely conforming to the surface of the article which is to be treated. The method includes the steps of placing the article between the members so as to create a relatively small bounded space between the article surface and the closely conforming member surface, drawing a vacuum in the bounded space, introducing an ionizable gas into the bounded space and applying an electric field between the members to create a plasma in the bounded space to react with the article surface.

Abstract: A tube is formed from a polycrystalline silicon carbide having a density of from 3.18 to 3.21 g/cm.sup.3, a maximum impurity content of 20 ppm, and imperviousness to fluids by a process which comprises precipitating the silicon carbide on the surface of a rod-shaped graphite structure by a chemical vapor-phase synthesis method and thereafter removing the graphite structure. A water-jet nozzle of high resistance to abrasive wear can be produced by using this tube as an inner tube thereof to form the flow path for a water jet to be ejected therethrough.

Abstract: Graphite substrate holders for employment in apparatus for chemical vapor deposition of diamond decrease the tendency of the formed diamond sheets to crack or shatter upon separation from the substrates. Said holders and the substrates therein preferably have rounded edges, to suppress crack formation at sharp corners. The holders are preferably coated, at least in part, with a tie-layer and a hydride-forming metal such as niobium. Also, certain maximum distances between the edges of the holder and substrates are preferably maintained in order to prevent contact of diamond with a heated filament employed for thermal activation.

Abstract: Methods for manufacturing a self-supporting substrate having a plurality of spaced-apart needles (spikes or microcapillaries) projecting upwardly from a major surface of the substrate. In a preferred method, metal is deposited onto a porous membrane such that the metal extends into the pores, after which the membrane is dissolved.

Abstract: Carbon coated carbide fibers are arranged in a predetermined pattern and shape around a silicon carbide coated graphite insert. Silicon carbide is infiltrated into the silicon carbide fibers to produce a SiC/SiC composite component. The SiC/SiC composite component is coated with glass and is then heated in air to burn out the graphite insert to form a hollow glass coated SiC/SiC composite component. The method is suitable for producing hollow SiC/SiC composite turbine blades or vanes.

Abstract: The invention provides a method of producing ultra-fine particles and an apparatus therefor. A particle carrier is moved in a chamber which is decompresed and charged with inert gas. An evaporable material is heated so as to deposit evaporated ultra-fine particles onto a part of the moving particle carrier. The deposited ultra-fine particles are collected from the part of the moving particle carrier while evaporated ultra-fine particles deposit onto another part of the moving particle carrier.

Abstract: An improved two membered substantially crack-free water jet mixing tube of an abrasive water jet cutting device and a method of its preparation. The method comprises chemically vapor depositing diamond layer on a funnel shaped support member to form an inner member of the mixing tube, separating the inner member from the support member, depositing and then cooling an outer member on the outer side of the inner member to produce a compressive stress on the inner member that substantially prevents formation cracks on the inner member. The inner side of the inner member has a smooth bore having a microcrystalline structure and the outer member has a higher coefficient of thermal expansion than diamond. The invention is also directed to a water jet cutting device that incorporates the aforementioned improved substantially crack-free water jet mixing tube.

Abstract: A process and apparatus for the manufacture of chemical vapor deposited silicon carbide which comprises conveying the reaction gases to a triangular chemical vapor deposition cell where material is deposited by chemical vapor deposition. The triangular cell provides a large surface area for deposition while occupying a minimum amount of the furnace floor surface area. The triangular cell has the added benefit in that deposited silicon carbide is of negligible thickness at the edges thereby permitting easy separation of material with a minimum of post deposition machining.

Abstract: A water-dispersible condensate of water-insoluble ultrafine particles of medicine or hormones having a particle size of at largest 4 .mu.m prepared by the steps of heating the medicine or hormone in a vacuum vessel at a temperature of 30.degree. C. higher than the boiling point and at a pressure between 0.01 Torr and 10 Torr to evaporate the medicine or hormone and condensing the medicine or hormone on a recovery plate to obtain the condensate.

Abstract: This invention offers a unique method to fabricate unique, straight, curved, or coiled tubes as small as 5 nanometers in diameter with wall thicknesses starting at about 1 nanometer. These tubes can be made from many materials such as polymers, ceramics and metals that can be applied to a surface of carbon, glass, or other tube forming fibers and then made to withstand the environment used to remove the fiber.

Abstract: A method of making a fiber-reinforced ceramic matrix composite of complex shape by first rigidifying a fibrous arrangement made of woven or braided material by impregnating with a preceramic resin, and then curing and pyrolyzing the resin to form a rigid or stiff preform. The rigid preform is then densified by chemical vapor infiltration, e.g., using a forced-flow/thermal-gradient process. Using three-dimensional woven fabrics made of ceramic fibers, such as silicon carbide or silicon nitride, strong high-temperature resistant composites are produced having porosities from about 20 percent to less than about 5 percent.

Abstract: A dielectric multilayer filter applicable to optical communication systems is disclosed, as is a fabrication method therefor, and an optical element incorporating the same. The disclosed dielectric multilayer filter includes a fluorinated polyimide base layer with a dielectric multilayer formed thereover. According to the disclosed fabrication method, a fluorinated polyimide layer is formed by applying liquid fluorinated polyimide material over a smooth surface to a predetermined thickness followed by drying and hardening, after which a dielectric multilayer is formed over the fluorinated polyimide layer by an ion assist vapor deposition method, and then stripping the fluorinated polyimide layer away from the underlying smooth surface. The disclosed dielectric multilayer filter can be easily and economically produced at a suitably small thickness with no need for grinding, exhibits highly uniform physical and optical properties, and is exceedingly durable and resistant to curling and warping.

Abstract: A method for making a free-standing synthetic diamond film of desired thickness, including the following steps: providing a substrate; selecting a target thickness of diamond to be produced, the target thickness being in the range 200 microns to 1000 microns; finishing a surface of the substrate to a roughness, R.sub.A, that is a function of the target thickness, the roughness being determined from ##EQU1## where t is the target thickness; depositing an interlayer on the substrate, the interlayer having a thickness in the range 1 to 20 microns; depositing synthetic diamond on the interlayer, by chemical vapor deposition, to about the target thickness; and cooling the synthetic diamond to effect the release thereof.

Abstract: Method and apparatus for producing a non-planar synthetic diamond structure of predetermined shape. A non-planar mandrel surface of the predetermined shape is provided and the mandrel surface is coated with a release substance. Synthetic diamond is deposited on the coating of release substance. The release substance is then activated to effect release of the deposited synthetic diamond structure. In a disclosed embodiment of the method of the invention a dome-shaped hollow mandrel is coated with a metal-containing substance, and synthetic diamond is deposited over the coating using a plasma jet deposition process. The metal containing substance is then heated to release the resultant diamond structure from the mandrel. In a form of the disclosed method, the metal-containing substance is a metal alloy which is highly polished before deposition of synthetic diamond thereon.

Abstract: Methods and apparatus for selectively depositing a layer of material from a gas phase to produce a part comprising a plurality of deposited layers. The apparatus includes a computer controlling a directed energy beam, such as a laser, to direct the laser energy into an unheated chamber substantially containing the gas phase to preferably produce photodecomposition or thermal decomposition of the gas phase and selectively deposit material within the boundaries of the desired cross-sectional regions of the part. At least one component of the gas phase is a vapor which condenses at a temperature above the ambient temperature of the chamber. Each such component can exist at a partial pressure no higher than its equilibrium vapor pressure at the chamber ambient temperature. For each cross section, the aim of the laser beam is scanned over a target area and the beam is switched on to deposit material within the boundaries of the cross-section.

Abstract: Process of mixing a fugitive plasticizer, e.g., ethylene carbonate, with moist particulate polyacrylonitrile then removing the water enabling adjustment of the melt viscosity for extrusion of the polyacrylonitrile into film, fiber, pellets and shaped articles. Stretching and heating the extruded polyacrylonitrile film or fiber causes the fugitive plasticizer to exude and vaporize from the film or fiber, carrying with it any remaining acrylonitrile monomer. The resulting film or fiber exhibits substantially increased molecular weight, thus enhancing the tensile strength and barrier properties of the polyacrylonitrile product. The process also produces polyacrylonitrile foam products. A novel cross-linking agent for polyacrylonitrile, divinyloxybutane, is disclosed. Thermostabilizing agents for polyacrylonitrile, N-maleimides and stilbene derivatives, are also disclosed.

Abstract: A polycrystalline diamond is prepared by chemical vapor deposition (step 101). A surface of the polycrystalline diamond is metallized (step 102). The metallized surface of the polycrystalline diamond is grooved with a YAG laser (step 103). A wedge or the like is driven into the grooves of the polycrystalline diamond to pressurize the same, whereby the polycrystalline diamond is divided along the grooves (step 104). Alternatively, a surface of a polycrystalline diamond prepared by chemical vapor deposition is grooved with a YAG laser (step 112), so that the surface of the polycrystalline diamond is metallized (step 113) after the grooving.

Abstract: Pyrolytic carbon products are manufactured so as to have improved structural properties. Pyrolytic carbon is deposited on a substrate in a fluidized bed of small particles at a temperature of about 1200.degree. to about 1400.degree. C., and after cooling to ambient temperature, the pyrolytic carbon is machined to desired physical dimensions for a heart valve component or the like. By heating such pyrolytic carbon structures in an inert gas atmosphere to a temperature in the range of about 1000.degree.-1500.degree. C. for at least about one hour following machining, it is found that stresses created in the pyrolytic carbon as a result of the machining are relieved without adverse effect to mechanical properties of the pyrocarbon, resulting in components having greater structural integrity.

Abstract: New intraocular lenses, fixation member assemblies for use in such lenses and methods for making the same. In one embodiment, the present invention involves a method for producing a fixation member assembly which includes exposing a fixation member component to a first plasma at conditions effective to enhance, relative to a substantially identical fixation member component which is not subjected to the exposing step, the bondability between the fixation member component and a polymeric coating to be located on the fixation member component; and exposing the fixation member to a second plasma in the presence of at least one material selected from polymeric components, polymerizable components and mixtures thereof at conditions effective to form the polymeric coating located on the fixation member component. Enhanced bondability between the polymeric coating-containing fixation member component and the optic of the intraocular lens and/or enhanced biocompatibility are preferably provided.

Abstract: In ceramic welding processes, oxidising gas and a mixture of refractory and fuel powders are projected against a surface and the fuel is burnt to generate sufficient heat that the refractory powder becomes at least partially melted or softened and a cohesive refractory mass is progressively built up against that surface. In order to reduce any tendency for the weld mass to include a low-grade refractory phase and thus promote the refractoriness of that weld mass, the fuel powder is present in a proportion of not more than 15% by weight of the total mixture and includes at least two metals selected from aluminium, magnesium, chromium and zirconium, and in that at least the major part by weight of the refractory powder consists of one or more of magnesia, alumina and chromic oxide, and in that the molar proportions of silica and calcium oxide present in the refractory powder (if any) satisfy the following expression: molar concentration of SiO.sub.2 in % .ltoreq.0.

Abstract: A method of producing a plasma treated article in a mold tool having electrically isolated mold dies including the steps of placing an article to be treated with a plasma between at least one of the dies and the article to be treated and applying an electric field between the dies to create a plasma in the space.

Abstract: Disclosed is an X-ray-permeable membrane for X-ray lithographic mask for fine patterning in the manufacture of semiconductor devices having good transparency to visible light and exhibiting excellent resistance against high-energy beam irradiation. The membrane has a chemical composition expressed by the formula SiC.sub.x N.sub.y and can be prepared by the thermal CVD method in an atmosphere of a gaseous mixture consisting of gases comprising, as a group, the elements of silicon, carbon and nitrogen such as a ternary combination of silane, propane and ammonia.

Abstract: The present invention provides a method of forming a free standing shape made of a material containing refractory metal, which entails providing a mandrel in a CVD enclosure, injecting a refractory halide gas and a reducing gas in the enclosure, reacting the gases in the enclosure to generate a material containing refractory metal, growing a layer of the material containing refractory metal on the mandrel and removing the mandrel to obtain the free standing shape, wherein the reducing gases is a silicon hydride gas or a mixture thereof.

Abstract: An improved method of producing transparent diamond laminates employs a substrate which is removed once a second layer is deposited over the diamond coating, thereby exposing a smooth diamond surface. The second coating should have a refractive index substantially identical to diamond, with zinc selenide and titanium dioxide being particularly preferred. Diamond films having two smooth surfaces may be produced by simultaneous deposition on parallel, opposed substrates until the two diamond films merge together to form a single film or plate, followed by removal of at least a portion of the two substrates.

Abstract: A process for making 2D and 3D carbon-carbon composites having a combined high crystallinity, high strength, high modulus and high thermal and electrical conductivity. High-modulus/high-strength mesophase derived carbon fibers are woven into a suitable cloth. Layers of this easily graphitizible woven cloth are infiltrated with carbon material to form green composites. The carbonized composite is then impregnated several times with pitch by covering the composite with hot pitch under pressure. The composites are given a heat treatment between each impregnant step to crack up the infiltrated carbon and allow additional pitch to enter the microstructure during the next impregnation cycle. The impregnated composites are then given a final heat treatment in the range 2500.degree. to 3100.degree. C. to fully graphitize the fibers and the matrix carbon. The composites are then infiltrated with pyrolytic carbon by chemical vapor deposition in the range 1000.degree. C. to 1300.degree. C. at a reduced. pressure.