Abstract: Essentially infusible/insoluble crosslinked polysilazanes, well adapted for pyrolysis and conversion into silicon carbide and/or silicon nitride ceramic materials, are produced by intimately contacting a fusible and organic solvent soluble polysilazane starting material with an effective crosslinking amount of gaseous triflic acid, CF.sub.3 SO.sub.3 H, and in which starting polysilazane the organic radicals directly bonded to silicon atoms are saturated and/or aromatic hydrocarbon radicals and such starting polysilazane being devoid of hydrogen atoms directly bonded to a silicon atom.
Type:
Grant
Filed:
June 11, 1991
Date of Patent:
June 23, 1992
Assignee:
Rhone-Poulenc Chimie
Inventors:
Jean-Jacques Lebrun, Charles Bobichon, Olivier Caix
Abstract: A method of preparing an organosilazane including reacting a first halosilane having the formula RR.sup.1 SiX.sub.2, wherein X is F, Cl, Br, or I, and each R and R.sup.1, independently, is X, H, or a lower alkyl group; a first primary amine compound having the formula R.sup.2 NH.sub.2, wherein R.sup.2 is H or a lower alkyl group; and a second primary amine compound having the formula R.sup.3 NH.sub.2, wherein R.sup.3 is H or a lower alkyl group, R.sup.3 being different from R.sup.2, to form the organosilazane.
Abstract: This invention relates generally to a novel method of forming self-supporting bodies and the novel products made thereby. In its more specific aspects, this invention relates to a method of producing self-supporting bodies comprising one or more boron-containing compounds by reacting a powdered parent metal with a bed or mass comprising a boron source material and a carbon source material (e.g., boron carbide) and/or boron source material and a nitrogen source material (e.g., boron nitride) and, optionally, one or more inert fillers. More specifically, the reaction occurs under the application of an externally applied pressure.
Abstract: Process for manufacturing of structural aggregate pigment products with intrinsically built-in functional properties, from aqueous dispersions of particulate matter treated with in-situ formed complex functional microgels with rapid formation kinetics.
Abstract: A curable resin binder comprising an epoxy resin which is a solid at room temperature, an epoxy resin curing agent which is inactive at room temperature, and as a curing accelerator, a pyridine derivative containing at least one hydroxyl group in a molecule. Also disclosed is a resin-bonded rare earth permanent magnet made by employing the binder and a powder of an alloy containing a rare earth metal or metals.
Type:
Grant
Filed:
November 22, 1989
Date of Patent:
May 19, 1992
Assignees:
Koei Chemical Co., Ltd., Sumitomo Metal Mining Co., Ltd.
Abstract: Disclosed is a correction fluid prepared by adding a stannous chelate compound having an acid phosphate ester of an aliphatic alcohol as a ligand to an aqueous acidic solution. The correction liquid forms a hydrophilic stannous chelate compound precipitate, when the pH value of the liquid is elevated. Accordingly, where the correction liquid is coated on the unnecessary line image part of an electrostatic master paper plate and the pH value of the thus coated liquid is elevated, the unnecessary line image part of the plate is to be coated with the hydrophilic and water-insoluble stannous chelate compound so that it becomes insensitive to ink. The operation for such correction may be effected at any stage before or after the lipophobication treatment of the electrostatic master paper plate to be corrected with the correction fluid.
Abstract: This invention relates to the preparation of highly densified ceramic bodies by the pyrolysis of a mixture comprising a preceramic borosiloxane, silicon carbide powder, a curing agent for the borosiloxane, a crosslinking agent for the borosiloxane and, optionally, additional components to facilitate sintering. Such highly densified ceramic bodies can be prepared by sintering under pressure or by a pressureless sintering process.
Abstract: An improved flatting agent comprising an inorganic hydrogel having a pore volume of at least 1.0 ml/g, an average particle size in the range 1 to 10 microns, and a particle size distribution such thatt when the flatting agent is dispersed in a coating, the fineness of grind is at least 4.75 on the Hegman scale. The inorganic hydrogel flatting agents of this invention are prepared by milling an inorganic hydrogel under controlled temperature conditions wherein a volatiles content of at least 40 weight percnet is maintained, to produce inorganic hydrogel particles characterized by a pore volume of at least 1.0 ml/g, an average particle size in the range of 1 to 10 microns, and a particle size distribution such that when the flatting agent is dispersed in a coating, the fineness of grind is at least 4.75 on the Hegman scale.
Abstract: Ternary CaO-TiO.sub.2 -SiO.sub.2 compositions are discussed. These compositions are useful as sintering aids for silicon nitride sintering. Use of these ternary compositions allows silicon nitride to be effectively sintered at lower temperatures than when conventional yttria sintering aids are used.
Abstract: This invention relates to terbium activated borate luminescent glasses exhibiting enhanced x-ray absorption characteristics and conversion of absorbed energy into green light due to incorporation therein of gadolinium oxide.
Type:
Grant
Filed:
November 16, 1990
Date of Patent:
April 28, 1992
Assignee:
Lockheed Missiles & Space Company, Inc.
Inventors:
Robert A. Buchanan, Clifford Bueno, Harold Berger
Abstract: An improved dry ground calcium carbonate filler is provided which is less sensitive to variations in relative humidity and does not promote premature viscosity increase in polyester molding compound. This filler is dry ground from a Caribbean micritic limestone to produce Class I and Class II fillers which are acceptable for use in polyester molding compound applications. A polyester molding compound containing this dry ground filler produces a composite having superior izod impact resistance and surface quality. In some situations filler loading levels may be increased 10-15% in the SMC/BMC without detrimental effects on the final composite.
Abstract: Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.
Type:
Grant
Filed:
June 6, 1990
Date of Patent:
April 7, 1992
Assignees:
Center for Innovative Technology, Virginia Tech Intellectual Properties, Inc., Virginia Polytechnic and State University
Inventors:
Jesse Brown, Deidre Hirschfeld, Dean-Mo Liu, Yaping Yang, Tingkai Li, Robert E. Swanson, Steven Van Aken, Jin-Min Kim
Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polycarbosilane in an organic solvent.
Abstract: The present invention relates to a method of forming ceramic matrix composite bodies comprising a parent metal reacting with an oxidant to produce an oxidation reaction product which infiltrates a loose unbonded mass or a preform comprising a filler material mixture. Specifically, the filler material mixture used in the method of the present invention comprises a material having varying compositions, sizes and/or shapes of filler material within the mass or preform. By utilizing a filler possessing varying compositions, sizes and/or shapes, enhanced packing of the filler material is achieved which may result in improved properties, such as erosion resistance, corrosion resistance, etc. Further, the use of filler material containing varying sizes and/or shapes may also enhance the growth rate of oxidation reaction product, thereby reducing processing times for formation of the resultant ceramic composite body.
Abstract: A galvanizing bath having a composition of about 5 ppm to about 100 ppm by weight aluminum, and rare earth elements by weight rated at zero and not exceeding about 5 ppm. In the method a galvanizing bath composition is maintained according to the foregoing in which aluminum and rare earth materials are added to the bath at a ratio greater than the ratio of the selected concentrations of rare earth materials and aluminum in the galvanizing bath.
Abstract: A hardened cement is prepared by mixing together two slurries, one comprising water and a cement component and the other comprising water, beta anhydrite and calcium oxide and or calcium hydroxide. According to the invention the cement component of the first slurry comprises ferrite and C.sub.12 A.sub.7 or A.sub.7 A--CX.sub.2 (where X is a halogen atom) and a reactive source of silica.
Abstract: A process for improving the strength of a sialon powder formed by a spray drying process is disclosed. The process involves the addition of small amounts of a hydrophilic silane to the slurry of inorganic powders and water which is fed to the spray dryer.
Abstract: A method for making insoluble detrimental heavy metals contained in a fly ash collected from an exhaust gas discharged from an incinerator. For the purpose of making insoluble the heavy metals, a chelating agent and water are added to the fly ash and these substances are kneaded to form a kneaded mass. The kneaded mass has a strong alkalinity under the effect of an alkaline substance added to the exhaust gas to remove hydrogen chloride and other detrimental components contained in the exhaust gas. The reactions between the heavy metals and the chelating agent in the kneaded mass are promoted by adjusting the amount of added water to limit a pH value of the kneaded mass to up to 12, thereby converting the heavy metals into water-insoluble chelate compounds through the reaction with the chelating agent.
Abstract: The semiconductor-containing glass disclosed herein is a semiconductor-containing glass which is produced by a sol-gel technique and which includes a semiconductor-containing glass characterized in the composition of a glass matrix and a semiconductor-containing glass characterized in the composition of a semiconductor. Either a semiconductor-containing glass has useful properties as a non-linear optical material.The method of producing semiconductor-containing glass disclosed herein is a method in which oxidization, volatilization or decomposition of a compound semiconductor or volatilization of a constituent element of the compound semiconductor by heat treatment for forming glass from a gel solid can be suppressed when a semiconductor-containing glass in which the compound semiconductor is dispersively precipitated is produced by a sol-gel technique.
Abstract: A heat-curable resinous coating composition comprising as a binder component(A) 5 to 90% by weight of a hydroxyl-containing resin selected from hydroxyl-containing acrylic resins and hydroxyl-containing polyester resins,(B) 5 to 50% by weight of an amino resin, and(C) 1 to 90% by weight of a crosslinkable resin selected from (C-a) polyfunctional resins having a number average molecular weight of at least 1000 and containing at least two carboxyl groups and at least two epoxy groups on an average per molecule and (C-b) polyorganosiloxanes having a number average molecular weight of at least 500 and containing at least two silanol groups on an average per molecule and if required, further containing an epoxy group.