Abstract: In a method for producing ceramic body by oxidation of a parent metal having a graded microstructure characterized by a plurality of zones differing from each other in one or more properties by altering the process conditions during formation of said ceramic body such that a zone of the oxidation reaction product formed posterior to said altering has one or more properties different from a zone of the oxidation reaction product formed anterior to said altering.
Type:
Grant
Filed:
November 16, 1992
Date of Patent:
November 30, 1993
Assignee:
Lanxide Technology Company, LP
Inventors:
Christopher R. Kennedy, Andrew W. Urquhart, Danny R. White, Marc S. Newkirk, Jeffrey R. Ramberg
Abstract: SiCxOy where x is greater than zero and up to about 2.0 and y is greater than zero and up to about 2.2 is produced from a cyclosiloxane polymer precursor by pyrolysis in the presence of oxygen by heating at a rate exceeding about 5.degree. C/min.
Type:
Grant
Filed:
April 2, 1992
Date of Patent:
November 30, 1993
Assignee:
Allied-Signal Inc.
Inventors:
Roger Y. Leung, John G. Sikonia, Stephen T. Gonczy
Abstract: Broadly, the present invention is directed to a method for making a thermally stable, dense, electrically conductive diamond compact. The method comprises infiltrating a mass of diamond crystals with a silicon infiltrant in the presence of boron under conditions comprising a temperature of not substantially above 1200 .degree. C. and a pressure of not substantially above 45 Kbars. The resulting compact contains diamond-to-diamond bonding. The boron can be provided in the form of boron-doped diamond. Alternatively, a boron-silicon alloy can be used for infiltrating boron-doped or undoped diamond. Further, boron can be added as elemental boron or B.sub.4 C with silicon for infiltration. Alternatively, boron metal catalyst plus silicon infiltration can be used for boron-doped or undoped diamond. Combinations of these techniques also can be used. In the HP/HT process, the silicon infiltrates the diamond powder mass forming a network composed of silicon carbide by reaction of the silicon with diamond-carbon.
Abstract: The present invention is directed to an alkali borosilicate frit which is capable of being applied to a metal substrate by the dry powder electrostatic process at a transfer efficiency of at least 70%, has a glass transition temperature of >525.degree. C. and contains, based on the total weight of the frit:______________________________________ Oxide Wt % ______________________________________ K.sub.2 O 6 to 10 Na.sub.2 O 5.5 to 9 LiO.sub.2 0 to 4 ZrO.sub.2 0 to 4 TiO.sub.2 0 to 4 ZnO 0 to 15 B.sub.2 O.sub.3 8 to 15 SiO.sub.2 40 to 60 La.sub.2 O.sub.3 3 to 9 CaO 0 to 15 F 0 to 2 Fe.sub.2 O.sub.3 0 to 3 CoO 0 to 5 NiO 0 to 5, ______________________________________wherein the total weight of CoO plus NiO is at least 1.The present invention is also directed to enamels for self-cleaning ovens containing these frits.
Type:
Grant
Filed:
December 9, 1992
Date of Patent:
November 23, 1993
Assignee:
Miles Inc.
Inventors:
Vernon J. Grebe, Elie E. Saad, Derek W. Sproson, Arthur C. Stidham
Abstract: A resistor paste comprising an inorganic component which consists essentially of from 20 to 70 wt % of glass powder and from 30 to 80 wt % of a powder selected from the group consisting of SnO.sub.2 power, Sb-doped SnO.sub.2 powder and a mixture thereof, wherein the glass powder consists essentially of from 12 to 50 wt % of SiO.sub.2, from 0 to 20 wt % of Al.sub.2 O.sub.3, from 0 to 40 wt % of MgO, from 0 to 40 wt % of CaO, from 0 to 60 wt % of SrO, from 16 to 60 wt % of MgO+CaO+SrO, from 0 to 10 wt % of Li.sub.2 O+Na.sub.2 O+K.sub.2 O+Cs.sub.2 O, from 0 to 10 wt % of PbO, from 0 to 20 wt % of ZnO, from 0 to 10 wt % of ZrO.sub.2 +TiO.sub.2, from 8 to 40 wt % of B.sub.2 O.sub.3, from 0 to 60 wt % of Ta.sub.2 O.sub.5, from 0 to 50 wt % of Nb.sub.2 O.sub.5, from 0 to 60 wt % of Ta.sub.2 O.sub.5 +Nb.sub.2 O.sub.5, and from 0.1 to 20 wt % of Fe.sub.2 O.sub.3 +CuO+NiO+CoO+MnO+MoO.sub.3 +WO.sub.3 +Cr.sub.2 O.sub.3 +Bi.sub.2 O.sub.3 +CeO.sub.2 +Sb.sub.2 O.sub.3 +In.sub.2 O.sub.3 +SnO.sub.2.
Abstract: A ceramic compact having excellent high temperature strength, toughness and reliability, which comprises a matrix preferably composed predominantly of silicon nitride and ceramic fibers uniformly dispersed in the matrix and orientated in a desired direction, said matrix and fibers being closely bonded by sintering. This compact is produced, for example, by preparing a shaped body of silicon, for example, in which ceramic fibers are uniformly dispersed by centrifugal casting and then heating and nitriding the shaped body in a nitrogen atmosphere to form a fiber-reinforced silicon nitride sintered compact. The ceramic fibers may include such fibers as aluminum oxide or silicon carbide fibers. Sintering assistants, such as silicon nitride, may be used to prepare the sintered compact.
Abstract: A process for coloring metal flakes by dispersing the flakes in an inorganic metal oxide sol to coat the flakes with the sol, dispersing the sol-coated flakes in a solution of an inorganic metal compound in a solvent, and thereafter heating the flakes for producing thereon a sol-gel coating that imparts to the flakes a visible color different from the color of the metal flakes when uncoated. The sol, the compound and the solvent are mutually selected to form the color-providing sol-gel coating on the metal flakes upon heating. Aluminum flake pigments are colored in this manner using an aqueous alkaline zirconia sol and a solution of cobalt nitrate in ethanol and/or water or a solution of iron nitrate in ethanol (followed, in the case of iron nitrate, by a treatment with ammonium hydroxide in ethanol). The steps of successively dispersing the flakes in the sol and solution may be repeated to intensify the produced color.
Abstract: Disc and monolithic (multilayer) ceramic capacitors having a fine grained barium titanate body exhibit a high dielectric constant and a smooth (X7R) temperature coefficient of capacitance. The start ceramic materials for making such capacitors are predominantly spherical barium titanate powder particles of average particle size less than 0.7 micron and of narrow particle size distribution. The barium titanate is mixed with around 2 weight percent of a the cadmium silicate flux, 3Cd.SiO.sub.2, serving as a reactivity and sintering promoting agent; and about one weight percent of a reactivity and sintering inhibitor agent, Nb.sub.2 O.sub.5. After preparing a green body of this mixture, the body is sintered at about 1100.degree. C.
Abstract: Oxides having a composition of (Ba.sub.1-x Sr.sub.x)O--Al.sub.2 O.sub.3 --2SiO.sub.2 are used as sintering aids for producing an improved silicon nitride ceramic material. The x must be greater than 0 to insure the formation of the stable monoclinic celsian glass phase.
Type:
Grant
Filed:
November 27, 1992
Date of Patent:
October 26, 1993
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
Inventors:
Narottam P. Bansal, Stanley R. Levine, William A. Sanders
Abstract: A precipitated silica paste is produced by dispersing precipitated silica in silicon oil. During the hydrophobing of precipitated silicas, the precipitated silica paste is added as a hydrophobing agent in the suspension phase. The product is spray-dried, tempered and ground.
Type:
Grant
Filed:
December 18, 1991
Date of Patent:
October 26, 1993
Assignee:
Degussa Aktiengesellschaft
Inventors:
Marian Chjonowski, Werner Nagel, Karl Meier, Wolfgang Leonhardt, Heinz Esch
Abstract: Colored corundum composite with a matrix of .alpha.-Al.sub.2 O.sub.3, as formed by sol-gel process ending in sintering and size reduction steps with addition of oxide pigments (or precursors of such oxide pigments, formable to the oxide pigment in sinter heating) added to the sol before full gelation thereof.
Type:
Grant
Filed:
July 8, 1992
Date of Patent:
October 26, 1993
Assignee:
H. C. Starck GmbH & Co. KG
Inventors:
Paul Moltgen, Gerhard Winter, Fister Dietmar
Abstract: Pigment preparations useful for preparing color ribbons contain from 20 to 40% by weight, based on the weight of the preparation, of a pigment based on carbon black, from 1 to 10% by weight, based on the weight of the preparation, of a dispersant based on a reaction product of polyhydroxystearic acid with an amine, and from 50 to 79% by weight, based on the weight of the preparation, of olein.
Abstract: A method for manufacture of Group IVB metal carbide comprising a carbide of a metal selected from the group consisting of titanium, hafnium and zirconium ceramic composites is provided wherein a permeable mass of filler and carbon is contacted with a molten Group IVB metal. The molten metal is maintained in contact with the permeable mass for a sufficient period to infiltrate the permeable mass and to react the molten metal with the carbon source to form a Group IVB metal carbide composite. The permeable mass may comprise a Group IVB metal carbide, or other inert filler, or a combination of filler materials.
Type:
Grant
Filed:
January 21, 1992
Date of Patent:
October 19, 1993
Assignee:
Lanxide Technology Company, LP
Inventors:
Adam J. Gesing, Edward S. Luce, Narashima S. Raghavan, Danny R. White
Abstract: Disclosed are neutral blue zirconium-vanadium pigments which do not display the disadvantages of previously known generic pigments, namely the high green component and the low color intensity and insufficient reproducibility in the case of neutral blue pigments. The neutral blue pigments with a rather high color intensity and good reproducibility are doped in the host lattice with phosphorus in addition to vanadium and are characterized by their color values in the CIE L*a*b* system. In order to produce such pigments, a zirconium-free mixture of powdery ZrO.sub.2, an SiO.sub.2 source, a vanadium compound and a phosphorus compound with an atomic ratio of Zr:Si:V:P=1:(0.95-1.10):(0.05-0.20):(0.005-0.03) as well as of a fluoride mineralizer is annealed after intensive grinding at 700.degree. to 900.degree. C.
Abstract: Spinel black pigments are prepared by annealing oxides, hydroxides or carbonates of copper, chromium and manganese and grinding the product. The manganese-yielding component is Mn.sub.3 O.sub.4.
Type:
Grant
Filed:
November 20, 1992
Date of Patent:
October 5, 1993
Assignee:
Bayer Aktiengesellschaft
Inventors:
Klaus Wussow, Peter Kuske, Manfred Mansmann, Dieter Messer, Dieter Rade
Abstract: The present invention relates to mineral fiber compositions useful for forming fibers which are readily degraded in a physiological medium such as that found within the human body. Advantageous compositions formed according to the present invention comprise the following components in the proportions by weight set forth below:______________________________________ SiO.sub.2 37 to 58 wt. %; Al.sub.2 O.sub.3 4 to 14 wt. %; CaO 7 to 40 wt. %; MgO 4 to 16 wt. %; P.sub.2 O.sub.5 1 to 10 wt. %; Fe.sub.2 O.sub.3 up to about to 15 wt. %; ______________________________________wherein the amount of CaO+MgO+Fe.sub.2 O.sub.3 is greater than 25% and the total amount of Na.sub.2 O+K.sub.2 O is less than 7%. The total iron contained within the composition is expressed in the form of ferric oxide (Fe.sub.2 O.sub.3).
Type:
Grant
Filed:
November 25, 1992
Date of Patent:
October 5, 1993
Inventors:
Sylvie Thelohan, Alain De Meringo, Hans Furtak, Wolfgang Holstein
Abstract: Colored marbled concrete and the process of producing same in a variety of different hues and color or colors by mixing dye into the primary mix, and then adding accent color or colors mixed separately and added gently to the primary mix to create a marble effect.
Abstract: A process and related compositions for lowering the electrical resistivity of ZrB.sub.2 are described. In a preferred embodiment, ZrH.sub.2 or Zr powder is blended with the ZrB.sub.2 powder and the composite is vacuum hot pressed at 2100.degree. C. The elemental Zr so formed can be beneficial by gettering impurities such as oxygen, nitrogen, and carbon, and by altering the overall ZrB.sub.2 stoichiometry, e.g., to ZrB.sub.1.97. Excess Zr is present in the matrix as a finely dispersed material. A variety of dopant materials can also be used to alter the electrical, thermal, and mechanical properties. Samples exhibiting this Zr-rich second phase exhibit lower electrical resistivities, higher thermal conductivities, better thermal shock resistance.
Abstract: Metal oxide group NTC theremistor material made from MnCO.sub.3 +NiO+CuO+Co.sub.3 O.sub.4 +FeO.sub.3 TiO.sub.2 group as a basic composition. The invention is characterized by metal oxide group thermistor material made from MnCO.sub.3 +NiO+ZnO+Co.sub.3 O.sub.4 +Fe.sub.2 O.sub.3 +TiO.sub.2 group or MnCO.sub.3 +NiO+CuO+ZnO+Fe.sub.2 O.sub.3 +TiO.sub.2 group as a basic composition having respectively composition amounts by weight for each ingredient described in the text. According to the invention, the sintering temperature of the material can be reduced relative to the conventional material, and therefore there is advantage that manufacturing expense of the thermistor can be reduced.
Type:
Grant
Filed:
January 21, 1993
Date of Patent:
September 21, 1993
Assignee:
Korea Institute of Science & Technology
Inventors:
Hyung J. Jung, Sang O. Yoon, Ki Y. Hong, Jeon K. Lee
Abstract: A method for the production of electrically conductive tin-IV-oxide of fine particle size is disclosed. Pursuant to the method, tin oxide and/or tin oxide hydrate is precipitated on a dihydroxy-tin-dichloride solution containing fluoride ions as doping agents. The precipitation is accomplished by adding alkali metal hydroxide, ammonium hydroxide, alkali metal carbonate or ammonium carbonate and the tin oxide and/or tin oxide hydrate is separated from the aqueous medium. The separated product is then calcined. The invention also discloses the use of the fluoride-doped tin-IV-oxide by adding it to the various vehicles.