Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

Abstract: A method of manufacturing a molten metal-resisting ceramic fiber composition includes mixing ceramic fibers, a frit, ceramic additives, a low temperature binder, and water. The mixture is formed into a desired shape, preferably by being extruded through a die. The shaped mixture is baked at low temperature, and then is fired at high temperature. During firing, the low temperature binder is oxidized and the frit is melted so as to substantially coat the fibers and fuse them into a porous matrix.

Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

Abstract: A method and means for the electronic processing of an analog signal generated in a series addressed diode array to produce a digital signal indicative of the illumination of the photodiodes in the array is disclosed. A voltage ramp is applied to the array and the resulting current steps converted to a voltage signal. The voltage signal is differentiated and the resulting pulses are digitized to provide the illumination state of the photodiodes in the array. Alternately, the voltage signal is integrated in a series of windows. The results of each previous integration is substrated from the most current integration, producing a series of pulses that are digitized to provide the illumination state of the array. The processing may be synchronized by either dividing the sweep interval into evenly spaced intervals, by differentiating the voltage signal and detecting the derivative exceeding a threshold, or differentiating the voltage signal twice and detecting zero-crossings in the resulting signal.

Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

Abstract: The present invention provides at least one cylindrical, close-ended porous, ceramic molten metal filter element connected to an essentially horizontal porous ceramic sealing plate filter element. The cylindrical element extends vertically above the elevation of that sealing plate. The molten metal flow is introduced to the exterior of the close-ended cylindrical elements and the upper surface of the plate element. The cylindrical filter body elements rest on the sealing plate, thus the sealing plate provides all of the structural support for the assembly. The molten metal flows through the porous ceramic material of the cylindrical elements and the sealing plate element to be further flowed downstream, ultimately to the associated casting molds.

Abstract: An oxygen-sensing element particularly for use in the exhaust stream of an internal combustion engine. In one embodiment, the sensing element may be a tubular solid electrolyte body with a transverse web forming a relatively shallow recess at one end of the body and a relatively deep tube at the other. Separate electrodes are formed on the surface of the body proximate the recess and on both opposing sides of the web. A porous plug disposed in the recess covers one of the electrodes. When the electrode on the surface of the body is exposed to the exhaust stream of a fuel-rich air-fuel mixture, the EMF across that electrode and the electrode on the underside of the web, which is exposed to fresh air, is indicative of the oxygen content of the exhaust stream.

Abstract: A high density planar array of substrate-supported, thin film diodes constituting photoresponsive semiconductor elements is placed between a document to be read and a light source for illuminating the document. The document is illuminated by the light source via windows in the array, reflected light from the document impinging on the photoresponsive elements constituted by the diodes which are electronically interrogated to provide a signal which is indicative of image information on the document. The light source directly illuminates small portions of each diode to establish a discharge or bias current that makes the array more sensitive and responsive. The high density diodes of the array can be formed in a manner that minimizes leakage current between adjacent diodes.

Abstract: Gas is dispersed into molten metal by immersing a shaft-supported impeller into the molten metal and by pumping gas through the shaft and out of the impeller. The impeller is in the form of a rectangular prism having sharp-edged corners that shear the gaas into finely divided bubbles. The particular shape of the impeller provides an especially effective bubble-shearing and bubble-dispersing action.

Abstract: Attachment hardware and modular furnace lining which may be secured to an interior surface of a furnace by any one of a variety of methods. e.g., welding, self-tapping screw, or to a previously secured stud or matingly configured member. In a preferred embodiment the module is formed of refractory ceramic fiber blanket portions which are retained into a modular unit by the hardware system. Each module includes hardware having support structure which passes through the layers of blanket adjacent the furnace wall. The hardware includes a collar which is moveable relative to the base bar to allow adjustment of the position of the module and means to facilitate access from the hot face of the module to install it.

Abstract: A method of preparing a surface of a silicon carbide article for joining by metal brazing to metal by micro-roughening that surface of the silicon carbide which is to be brazed, applying catalyst consisting essentially of aqueous PdCl.sub.2 directly to the micro-roughened surface, in the absence of pretreatment of said surface with stannous chloride, and electrolessly depositing a thin layer of metal selected from the group consisting of Ni, Cr, Au, Ag and Cu on said catalyst-treated surface.

Abstract: A method of manufacturing a molten metal-resisting ceramic fiber composition includes mixing ceramic fibers, a frit, ceramic additives, a low temperature binder, and water. The mixture is formed into a desired shape, preferably by being extruded through a die. The shaped mixture is baked at low temperature, and then is fired at high temperature. During firing, the low temperature binder is oxidized and the frit is melted so as to substantially coat the fibers and fuse them into a porous matrix.

Abstract: Attachment hardware and modular furnace lining which may be secured to an interior surface of a furnace by any one of a variety of methods, e.g., welding, self-tapping screw, or to a previously secured stud or matingly configured member. In a preferred embodiment the module is formed of refractory ceramic fiber blanket portions which are retained into a modular unit by the hardware system. Each module includes hardware having support structure which passes through the layers of blanket adjacent the furnace wall. The hardware includes a collar which is movable relative to the base bar to allow adjustment of the position of the module and means to facilitate access from the hot face of the module to install it.

Abstract: A thermal insulation is formed by simultaneously spraying ceramic fibers and a binder at a surface to be covered. An aqueous binder is prepared prior to application to the fiber during the spraying operation. The binder includes an organic component which provides necessary wet and green adhesion to the substrate surface and wet and green cohesion to the newly formed lining prior to firing of the sprayed-on layer. The binder also includes an inorganic component which functions at and after exposure to a high temperature to secure the ceramic fibers to the substrate and to one another. Drying and firing of the layer develops strength in the inorganic binder. Known ceramic fibers such as alumina-silica amorphous fibers, alumina-silica-zirconia fibers, polycrystalline mullite fibers, alumina fibers, mineral fibers, or combinations thereof, and the like may be employed. The fiber may be precoated with the organic binder.

Abstract: Attachment hardware and modular furnace lining which may be secured to an interior surface of a furnace by any one of a variety of methods. E.g., welding, self-tapping screw, or to a previously secured stud or matingly configured member. In a preferred embodiment the module is formed of refractory ceramic fiber blanket portions which are retained into a modular unit by the hardware system. Each module includes hardware having support structure which passes through the layers of blanket adjacent the furnace wall. The hardware includes a collar which is moveable relative to the base bar to allow adjustment of the position of the module and means to facilitate access from the hot face of the module to install it.

Abstract: New arsenate compounds, compositions and solid diffusion sources for the arsenic doping of semiconductors are disclosed which comprise substances composed of a sintered arsenate that decomposes upon heating at temperatures between 500.degree.-1400.degree. C. to release As.sub.2 O.sub.5, As.sub.2 O.sub.3 and/or elemental arsenic vapors for transport to semiconductor elements as a controlled dopant.

Abstract: Dense, strong, composite materials are produced from mixtures of silicon and silicon carbide. The composite materials are characterized by a mixture of finely-divided silicon carbide in a substantially continuous matrix of silicon. The composite materials contain from about 40 to about 60 percent by volume silicon carbide and from about 60 to about 40 percent by volume silicon. The composite materials are produced by initially producing a finely-divided silicon carbide starting component and forming the component into a green body of the desired shape. The green body is subsequently impregnated with molten silicon in the absence of any substantial amount of carbon. Suitably, a thermoplastic resin binder may be added to the silicon carbide starting material to aid in forming the green body. The impregnation step may be carried out by surrounding the green body with finely-divided silicon metal and heating the covered body to a temperature above the melting point of silicon.

Abstract: A fluid bed reactor for treatment of refractory materials with a hot fluidizing gas and a method to use same. Both the refractory materials and the fluidizing gas are introduced from the top of the reactor. Unusually high reaction temperatures of up to 2000.degree. C. are maintained in the reaction chamber due to the presence of heating elements within the reactor and due to countercurrent heat transfer.

Abstract: Fused cast refractory moldings having a random microstructure, which are near in size and configuration to the desired final shape, and process and apparatus used in their manufacture are described. The process includes rapid melting of the refractory material followed by controlled rapid cooling. Laminated composite fused cast refractories may be produced.

Abstract: An array for sensing the relative intensity of electromagnetic radiation at a plurality of locations employs a network of photodiodes and non-photoresponsive diodes. A first terminal of each photodiode, e.g. the anode, is electrically connected to a common point which is one terminal of the array. The non-photoresponsive diodes are connected in like-polarity series. The second terminal of each photoresponsive diode is connected to a different connection of non-photoresponsive diodes in the string. The array is scanned with a voltage ramp signal and each change in current flow indicates an illuminated diode. The particular voltage at which current flow changes discloses which photodiode is illuminated. Embodiments of the novel array can be made monolithically without a significant number of conductor cross overs.