Abstract: A steel honeycomb extrusion die having an array of feedholes extending into a die inlet face and intersecting with an array of discharge slots on the die discharge face is made by a process wherein the slots are cut into blind feedholes by wire EDM slotting while dielectric fluid is provided in or flushed through the feedholes. The resulting improvements in EDM process stability reduce the number of wire electrodes broken during machining of the array, and in feedhole/slot intersection configuration and finish, provide dies with improved extrusion performance and extended service life.

Abstract: Assembly and method of installing an electrode of a predetermined size and configuration in an electric heater envelope having an electrode opening at a preselected position. The assembly and associated method consist of affixing a hollow compression fitting about or within the electrode opening and providing a sleeve of a refractory deformable dielectric material within the fitting through which the electrode passes into the envelope. Dielectric spacing means are positioned between the electrode and electrically conductive portions of the fitting or envelope to prevent electrical conduction therebetween. Compression fastening means are then provided, securable to the fitting, to impart sufficient compressive force to the assembly to deform the sleeve about the electrode, thereby effectively sealing and securing the electrode within the fitting without the electrode grounding against the fitting or the envelope.

Abstract: High silica glasses exhibiting blue color by transmitted light are produced by impregnating a porous, high silica glass with a solution of cobalt, aluminum, and selected alkaline earth or alkali salts, and then consolidating the glass under oxidizing conditions to dope the glass with the corresponding oxides. The tinted glass has particular utility as a blue filter for lighting applications.

Abstract: Thermoplastic binder compositions comprising a high molecular weight polymer component and a molten wax component are compounded with sinterable ceramic or other inorganic powders. Upon cooling, a thermally reversible gel is formed in the binder by the gelation of the polymer in the molten wax. Ceramic batches comprising these binders behave as shear-thinning and thermally reversible gels. They exhibit substantially improved dewaxing performance and, preferably, extensibility sufficient for sheet reforming processes.

Abstract: A composite including an inorganic substrate having an outer surface from which pores extend into the substrate and a coating extending over the substrate's outer surface as a substantially uninterrupted layer of carbon. The coating penetrates into the pores of the inorganic substrate. The composite can be made by a process including the steps of contacting an inorganic substrate with a coating and impregnating liquid consisting essentially or wholly of a carbon precursor liquid, treating the inorganic substrate under conditions effective to cure substantially the carbon precursor liquid, and heating the inorganic substrate under conditions effective to convert substantially the cured carbon precursor liquid to carbon.

Abstract: Fiber-reinforced ceramic matrix composites are fabricated by a process wherein a fiber reinforcement material, preferably in the form of a fiber array or ribbon of parallel-aligned monofilament fibers, is combined with multiple sheets of ceramic matrix material, preferably in the form of thin flexible ceramic tape. A preform consisting of a layered assembly of the fibers and ceramic matrix sheet is consolidated with heat and pressure into an integral, substantially void-free ceramic matrix composite wherein the matrix has fully penetrated and infiltrated the fiber array and wherein the fibers are disposed in precise alignment and position, following the fiber alignment in the preform.

Abstract: Extrusion die apparatus and an extrusion method for extruding large-cross-section honeycomb structures from plasticized ceramic batch materials are described, the apparatus comprising a die having a support rod connected to its central portion, the support rod being anchored to support means upstream of the die. The support rod and support means act to limit die distortion during extrusion, reducing die strain and stress to levels permitting large honeycomb extrusion without die failure. Dies of optimal thickness are disclosed which reduce the maximum stresses exerted on the die during extrusion.

Abstract: A lead construction for a fluid heater such as an electrically heated catalytic converter, is set forth including a mineral insulated cable having a central core connected to the heater element of the fluid heater, an outer metal sheath connected to an enclosing housing for the fluid heater, and electrical insulation between the central core and the outer sheath.

Abstract: Flow-through fluid heaters useful, e.g., for the preheating of exhaust gas streams prior to catalytic treatment thereof, are made by bonding an electrically conductive metallic film or foil to at least one pre-sintered flexible ceramic foil substrate to provide a flexible, electrically conductive ceramic/metallic heating element, that element then being formed into a crimped sheet or base sheet for incorporation into a honeycomb structure which includes a plurality of open channels extending from one surface of the structure to another surface of the structure, formed by one or more contacting combinations of crimped sheet and base sheet. Catalytic coatings may be applied to the preheaters to provide a heater/converter with very rapid light-off characteristics.

Abstract: A process is set forth for electrochemically machining holes in a workpiece, such as a die, in such a manner so as to virtually eliminate surface finish patterns normally introduced by the electrochemical machining process, by randomly forming sequences of patterns of holes extending in rows across the workpiece along its extent, and then rotating the workpiece 180.degree. and randomly forming additional sequences of patterns of holes across the workpiece adjacent those sequences of holes which were formed prior to rotating the workpiece 180.degree..

Abstract: A method is set forth for slotting a workpiece by utilizing an EDM-wire cutting method wherein detrimental effects of an intrinsic slot taper produced by EDM wire cutting are compensated for and averaged out by alternating the direction of the wire entrance and exit along adjacent slots formed in the workpiece.

Abstract: Secondary discharge slots are cut into the face of newly made or used extrusion dies such that the secondary discharge slots communicate transversely and longitudinally with primary discharge slots but do not communicate with the feed holes. The novel extrusion die arrangement is set forth for the production of ceramic honeycomb structures which produce a greater number of cells per square inch, protrusions on the cell walls, or a combination of both dependent upon the Primary Slots' Volume to Secondary Slots' volume ratio. The secondary discharge slots can produce honeycomb substrates with much greater surface areas, using an extrusion die with a significantly reduced number of feed holes and a greater number of discharge slots.

Abstract: A composite including an inorganic substrate having an outer surface from which pores extend into the substrate and a coating extending over the substrate's outer surface as a substantially uninterrupted layer of carbon. The coating penetrates into the pores of the inorganic substrate. The composite can be made by a process including the steps of contacting an inorganic substrate with a coating and impregnating liquid consisting essentially or wholly of a carbon precursor liquid, treating the inorganic substrate under conditions effective to cure substantially the carbon precursor liquid, and heating the inorganic substrate under conditions effective to convert substantially the cured carbon precursor liquid to carbon.

Abstract: Electrically conductive honeycomb structures are provided for use as catalytic converters, pre-heaters for catalytic converters, or particulate filters. The honeycomb structures are composed of subunits which are arranged to produce a serpentine conductive path through the honeycomb. The serpentine path gives the honeycomb an increased electrical resistance so that elevated temperatures can be achieved with less current. The subunits allow the serpentine current path to be produced without any slitting or cutting of the honeycomb.

Abstract: In a process of forming cordierite-containing bodies, the water absorption capability or shrinkage of the bodies is controlled using the alumina-yielding ingredients. The process of controlling the water absorption capability or shrinkage includes the steps of providing alumina-yielding ingredients in the form of two aluminas having different particle sizes, wherein the ratio of the two particle sizes is in the range of from about 3:1 to 30:1 or 1:3 to 1:30. Next, a linear relationship between the cordierite-containing body's water absorption capability or shrinkage and the relative percentage of the alumina-yielding ingredients made up by the two aluminas is determined. After determining the linear relationship, a water absorption capability or shrinkage of the cordierite-containing body is selected in accordance with that relationship by adjusting the relative percentages of the two aluminas.

Abstract: Inorganic reinforcing fibers comprising hybrid BN--C protective coatings containing up to 12% by weight of hexagonal (graphitic) carbon dissolved in the BN matrix but being essentially free of undissolved pyrolytic and graphitic carbon secondary phases, and fiber-reinforced ceramic matrix composite products incorporating the protectively-coated fibers, are disclosed. The fibers resist oxidation and provide good bonding interface characteristics when disposed in ceramic encapsulating materials, such that the composite products exhibit excellent resistance to high temperature embrittlement.

Abstract: Inorganic reinforcing fibers provided with a multi-layer protective coating comprising a boron nitride sublayer and an oxide-based overcoating of alumina or synthetic mica, and fiber-reinforced ceramic matrix composite products incorporating the protectively-coated fibers, are disclosed. The fibers offer improved oxidation resistance and good compatibility with oxide-based glass and glass-ceramic composite matrix materials.

Abstract: Thin-walled honeycomb structures of activated carbon, useful for the adsorption of hydrocarbon vapors are prepared without the need for firing or sintering at elevated temperatures. The structures are prepared by forming a substantially homogeneous batch from an admixture of thermally gellable cellulose ether and/or derivative thereof such as methylcellulose, an additional organic binder such as a polyvinyl alcohol resin, and particles of activated carbon; plasticizing the batch with liquid, extruding the batch into a honeycomb shape; and drying the extruded shape at a temperature up to about 225.degree. C.

Abstract: A vapor-phase method for treating a beta-spodumene ceramic article to achieve a substitution of exchangeable hydrogen ions for the lithium present in the beta-spodumene crystals, wherein a barrier between the ceramic article and the source of exchangeable hydrogen ions is maintained in order to prevent lithium contamination of the hydrogen ion source and to generate highly recoverable lithium salts, is provided.

Abstract: A method of preparing a monolithic catalyst support having an integrated high surface area phase is provided. A plasticized batch of ceramic matrix material intimately mixed with high surface area powder is formed into the desired shape for the monolith and then heated to sinter the ceramic. The resulting monolith has a strong substrate of the ceramic matrix material and a high surface area phase provided by the high surface area powder extruded with the batch.