Abstract: The invention relates to subjecting boron carbide to a heat treatment at a temperature within a range of 1250.degree. C. to less than 1800.degree. C. prior to infiltration with a molten metal such as aluminum. This method allows control of kinetics of metal infiltration and chemical reactions, size of reaction products and connectivity of B.sub.4 C grains and results in cermets having desired mechanical properties.

Abstract: A method for making submicrometer metallic carbides and submicrometer solid solution metallic carbides from sources of at least one metallic oxide and carbon involves the rapid heating of a reactive particulate mixture of at least one metallic oxide and carbon in order to achieve a resulting particulate size of less than 1 micrometer. Submicrometer sized metallic carbides and solid solution metallic carbides have found great use in commercial ceramic applications. It has been found that the smaller sized particles produce a product having superior toughness and hardness. In addition, the submicrometer sized solid solution metallic carbide resulting from this method is also disclosed.

Abstract: A silicon nitride-based powder composition that yields sintered bodies having a density of at least 3.15 g/cm.sup.3 by pressureless sintering. The composition includes silicon nitride and an amount of bismuth oxide as a phase transition aid in addition to magnesium oxide, aluminum oxide, zirconium oxide and, optionally, silicon dioxide. The sintered bodies can be produced at temperatures of 1650.degree. C. or less.

Abstract: A method for forming monotungsten carbide, comprising heating a solid, non-elemental tungsten-containing material in a flowing atmosphere containing molecular hydrogen and molecular methane for a time sufficient to convert substantially all of the tungsten-containing material to monotungsten carbide, The heating brings the temperature of the tungsten-containing material to a first elevated temperature of from about 520 to about 550.degree. C. and, subsequently, at a rate of from about 3 to about 10.degree. C. per minute, the heating brings the temperature from the first elevated temperature to a second elevated temperature of about 800 to about 900.degree. C. Thereafter the temperature is held at the second elevated temperature for at least about 15 minutes. At least about 50 weight percent of the monotungsten carbide formed is formed while holding the temperature at the second elevated temperature.

Abstract: Carbothermally reduce a metal oxide to its corresponding metal nitride or metal carbide powder in a vertical gravity flow reactor by adding precursor pellets containing the metal oxide, a thermally decomposed binder material and carbon or a source of carbon directly to a heated reaction zone within the reactor. The pellets form a pellet bed, the top of which must be maintained within the heated reaction zone. The binder material is a blend of wheat and corn starches, optionally in conjunction with another binder such as melamine. The binder material thermally decomposes to a carbonaceous residue which functions both as an additional source of carbon and as a binder for the precursor pellets. The reactor may be modified by adding an internal vent line to remove volatile materials from the heated reaction zone before they have an opportunity to condense on internal reactor surfaces.

Abstract: An aluminum nitride powder that has substantially no ammonia odor after exposure to atmospheric moisture is obtained by admixing the powder with a gettering compound that sublimes or decomposes at a temperature below 500.degree. C. The gettering compound is a C.sub.1 -C.sub.11 aliphatic carboxylic mono- or polyfunctional acid, an anhydride or an ester of such an acid or an anhydride of an aromatic carboxylic acid.

Abstract: A powder composition consisting essentially of an intimate mixture of boron carbide and titanium diboride, the mixture having an average particle size of less than about 0.5 micron, the particles being uniformly dispersed such that elemental analytical techniques show all discrete concentrations of boron carbide and titanium diboride to be less than or equal to about 0.5 micron in diameter, is disclosed. The powder is useful for making a densified ceramic composition comprising titanium diboride grains, having an average grain size of less than or equal to about 3 microns in diameter, uniformly dispersed with boron carbide grains, having an average grain size of less than about 5 microns in diameter. The densified composition exhibits improved hardness and toughness when compared wiht titanium diboride or boron carbide compositions.

Abstract: A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, a densification aid such as sodium oxide, a conversion aid such as lanthanum oxide and a compound, such as gallium oxide, which enhances growth of .beta.-silicon nitride whiskers-under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness and high fracture strength is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing the densification aid, the conversion aid, the compound which enhances growth of .beta.-silicon nitride whiskers, and an amount of silica; and not greater than about 10 weight percent of the total weight as other phases.

Abstract: A composition comprising a ceramic material and, as a binder, poly(ethyloxazoline).

Abstract: By supplying gaseous nitrogen throughout a discrete aliquot of a preferably pelletized mixture of aluminum oxide, carbon and, optionally, calcium oxide during the carbothermal reduction thereof to aluminum nitride and continuously removing gaseous reaction products therefrom, a high quality aluminum nitride is produced. One means of supplying gaseous nitrogen to the mixture of solid reactants is a perforated tray having a hollowed-out bottom. Gaseous nitrogen supplied to the hollowed-out portion flows through the perforations and throughout solid reactants contained in the tray. The carbon may be alternatively supplied, in whole or in part, as a gaseous reactant.

Abstract: A powdered admixture of a boron, carbon, nitrogen or silicon derivative of a first metal, e.g., tungsten carbide, and a source of a second metal, e.g., molybdenum subcarbide when the second metal is molybdenum, is, when subjected to densification conditions, partially reacted and converted to a hard, wear resistant material. Such a material, formed from an admixture of tungsten carbide and molybdenum subcarbide, contains tungsten monocarbide and at least one mixed tungsten/molybdenum carbide. This material has a Vickers hardness of at least about 2200 kg/mm.sup.2 measured using a 1 kg load. Articles formed from this material can be useful as, for example, nozzles in abrasive or nonabrasive waterjet cutting machines and various parts of wire drawing apparatus.

Abstract: A process for preparing reinforced thermoset articles of manufacture from a lofted composite sheet employed as a skeleton or preform which is impregnated with a thermoset resin composition and cured. A reinforced thermoset article of manufacture prepared from a lofted composite impregnated with a thermoset resin composition and cured is also provided.

Abstract: A method for filtering liquid or gaseous materials where the filtration is conducted with a porous filter media prepared from an aqueous wet-laid, lofted fiber-reinforced composite sheet, the composite sheet comprising a heat fusible polymer, reinforcing fibers and a binder. The random fiber composite sheet can be selectively lofted or recompressed to form filter media having variable porosity. Also, a membrane support means prepared by applying or treating the fiber-reinforced composite sheet with a discriminating membrane layer.

Abstract: A novel electrochemical cell monitoring apparatus for a caustic-chlorine electrolyzer, which includes a voltmeter, a standard calomel reference electrode, a flexible conduit for cell bath, preferably of multilayer construction, and a conduit support body placed between electrode walls to prevent crimping of the conduit when the walls of the electrolyzer are pressed together or dislocation during operation, and the method of monitoring a selected electrochemical cell which includes connecting an electrode of the selected cell and the standard reference electrode to the voltmeter, providing cell bath from the electrode of the selected cell through the conduit to the liquid junction of the standard reference electrode, operating the electrolyzer and reading the voltage on the voltmeter to compare with a predetermined standard voltage.

Abstract: A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, magnesium oxide, yttrium oxide and calcium oxide under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing magnesium oxide, yttrium oxide, calcium oxide, and silica in a total amount not greater than about 35 weight percent; and not greater than about 10 weight percent of the total weight as other phases.

Abstract: A coal gasifier slag composition, and process utilizing a coal gasifier slag composition for the removal of a metal ion, or the ions of a plurality of metals, from an aqueous medium by contact of said coal gasifier slag composition with said aqueous medium. The coal gasifier slag, which is regenerable by contact with a dilute acid, is employed as a contact mass for the removal from an aqueous medium of a metal ion, or the ions of a plurality of metals, derived from Groups IB through VIIB, IIA through VA, and VIII of the Periodic Table of the Elements. The coal gasifier slag is useful for removing a metal ion, or the ions of a plurality of metals, from industrial waste water, groundwater, mine water and the like, or as a landfill, or as a protecting layer adjacent to or surrounding land fills, surface impoundments, tank farm beds and the like.

Abstract: A process is provided for metallating ethylene polymers which have polymerized therein a minor amount of nonconjugated diene. Metallation is accomplished with a blend of three metallating reagents: (a) an alkyllithium compound; (b) a potassium alkoxide; and (c) a chelating tertiary diamine. The metallated polymers so prepared may be reacted with one or more anionically polymerizable monomers to form graft polymers or with a reagent such as carbon dioxide to form a functionalized polymer. When the anionically polymerizable monomer has two or more polymerizable sites, the metallated polymer is reacted with a modifying compound such as alpha-methylstyrene before it is reacted with the monomer(s). Certain of the graft polymers behave as thermoplastic elastomers whereas others are thermoplastic. The blend of metallating reagents may be used with any polymer having partial or complete unsaturation.

Abstract: This invention relates to a two-fluid nozzle which is adjustable to provide a substantially constant mixing energy. Adjustment of the two-fluid nozzle is made in accordance with the pressure and mass flow values of the liquid and gas fed to the nozzle. A microprocessor calculates the mixing energy from these values and provides an output to the nozzle to adjust it should its mixing energy be in variance with a pre-selected mixing energy.

Abstract: A flow-through electrochemical cell for sequentially oxidizing and reducing an aryl compound. The cell includes a cell body forming a compartment to hold an aqueous electrolyte solution, a porous anodic electrode, and a porous cathodic electrode. The anodic electrode includes a first porous layer of a hydrophobic material, a second porous layer with an oxidation catalyst dispersed therein, and a current collector in electrical contact with the second layer. The cathodic electrode comprises a block of a porous, electrically-conductive material impregnated with lead particles. The cell is particularly useful for the preparation of aryl hydroquinones at very high current efficiencies, high current densities, and low voltages.

Abstract: A flow-through electrochemical cell for sequentially oxidizing and reducing an aryl compound. The cell includes a cell body forming a compartment to hold an aqueous electrolyte solution, a porous anodic electrode, and a porous cathodic electrode. The anodic electrode includes a first porous layer of a hydrophobic material, a second porous layer with an oxidation catalyst dispersed therein, and a current collector in electrical contact with the second layer. The cathodic electrode comprises a block of a porous, electrically-conductive material impregnated with lead particles. The cell is particularly useful for the preparation of aryl hydroquinones at very high current efficiencies, high current densities, and low voltages.