Patents Assigned to TAM Ceramics, Inc.
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Patent number: 5646080Abstract: A sinterable dielectric ceramic powder composition comprising 95 to 98 parts by weight of a major ingredient consisting of 97.0 to 99.5 mole % barium titanate, 0.5 to 3.0 mole % magnesium oxide or a precursor therefor and 0 to 2.0 mole % manganese oxide or a precursor therefor and 0 to 0.2 mole % cobalt oxide or a precursor therefor; 2 to 5 parts by weight of a minor ingredient consisting of a ternary mixture of 15 to 30 mole % barium oxide or a precursor therefor, 15 to 30 mole % silicon dioxide or a precursor therefor and 40 to 70 mole % calcium titanate, which composition can be fabricated into multilayer ceramic capacitors with nickel, nickel alloy, palladium or palladium/silver alloy inner electrodes, the so formed capacitors having a variation of capacitance with temperature of less than .+-.20% over the range -55.degree. C. to 140.degree. C. as compared to the value at 25.degree. C. and not containing any second phases after sintering.Type: GrantFiled: November 20, 1995Date of Patent: July 8, 1997Assignee: Tam Ceramics, Inc.Inventors: Mike Ssu-Hai Chu, John Bultitude, Michael Rand, Kay Louise Nimmo, Ian Thompson, Christopher Hood
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Patent number: 5550092Abstract: A sinterable ceramic composition which comprises a barium titanate based dielectric precursor powder which has a temperature coefficient of capacitance, TC, of .+-.15% over the temperature range -55.degree. to 125.degree. C., in admixture with from 0.25 to 2.0% by weight of an additive which is selected from the group consisting of ZrSiO.sub.4, Al.sub.2 O.sub.3, SiO.sub.2, precursors therefor and mixtures thereof, the composition having an average particle size in the range of from 0.6 to 0.8 micrometers and, when fired, having a dielectric constant of above 2500, a TC of .+-.15% over the temperature range of -55.degree. to +125.degree. C. and a porosity of less than 0.7% with no pores greater than 3.5 micrometers average diameter.Type: GrantFiled: February 10, 1995Date of Patent: August 27, 1996Assignee: Tam Ceramics Inc.Inventors: Mike S.-H. Chu, John Bultitude, Christopher Hood
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Patent number: 5461014Abstract: A ceramic composition which includes Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 or the oxide precursors thereof, in admixture with barium copper oxide of the formula BaCuO.sub.2 as a sinter aid therefor. The compositions do not contain any free lead oxide and have high dielectric constants, e.g. above 8000, and low loss factors, e.g. below 3%.Type: GrantFiled: January 13, 1994Date of Patent: October 24, 1995Assignee: TAM Ceramics, Inc.Inventors: Mike S. Chu, Daniel C. Rose, John Bultitude
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Patent number: 5362693Abstract: The present invention provides ceramic compositions for preparing multi-layer capacitors (MLCs) having high dielectric constants between about 3000 and 4700 and stable temperature coefficients (TC) prepared from high purity barium titanate, niobium pentoxide, and cobalt oxide.Type: GrantFiled: November 12, 1993Date of Patent: November 8, 1994Assignee: Tam Ceramics, Inc.Inventors: Mike S. H. Chu, Susan E. Corah
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Patent number: 5279639Abstract: This invention relates to the refining of steel external to a primary steelmaking vessel, for example in the ladle. More particularly, it is: A.) a method of synthesizing a slag on the steel that (i) mitigates the detrimental effects of existing natural slag carried over from the primary steelmaking vessel, (ii) is low in specific bulk density, due to gas evolution and foaming, (iii) is suitable for refining of steel, and (iv) is not aggressive to the ladle refractory lining; B.) a method, and composition for treating any primary slag that has entered the ladle; C.) a method and composition for coating refractory linings. The present invention involves the manufacture in situ of a secondary ladle slag, the treating of ladle slag, and the protection of refractory linings by the addition of materials including calcium carbide, foaming agents such as one or more carbonates of calcium, magnesium, and sodium, and other components used to adjust slag composition.Type: GrantFiled: April 6, 1990Date of Patent: January 18, 1994Assignee: Tam Ceramics, Inc.Inventors: Frank L. Kemeny, David J. Sosinsky
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Patent number: 5262368Abstract: A method of sintering a ceramic material composed of alkaline earth metal titanate and mixtures thereof, wherein the ceramic material is mixed with a sintering aid of a mixture of a mixed metal oxide of the formula BaCuO.sub.2 and an oxide selected from the group consisting of tungsten trioxide, molybdenum trioxide and mixtures thereof, and sintering the mixture.Type: GrantFiled: November 19, 1991Date of Patent: November 16, 1993Assignee: TAM Ceramics, Inc.Inventors: Christopher Hood, John F. Clifford, Timothy P. Beales, John Bultitude
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Patent number: 5147579Abstract: The present invention provides free flowing and moisture resistant compositions from normally hygroscopic compositions by a process of mixing the hygroscopic material with a sealing material and heat treating. By controlling the sealing material added, the heat treatment time, and the heat treatment temperature, the sealing material forms a glassy coating on the hygroscopic material that is impervious to moisture while retaining free-flow properties. The present invention particularly provides free-flowing and moisture resistant sodium titanate and potassium titanate compositions having a moisture pick-up =< about 0.5 wt. % by a process of mixing sodium titanate or potassium titanate with a sealing material and heat treating the mixture.Type: GrantFiled: July 17, 1989Date of Patent: September 15, 1992Assignee: Tam Ceramics, Inc.Inventor: Terence C. Dean
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Patent number: 5029042Abstract: The present invention provides ceramic compositions for preparing multi-layer capacitors, having high dielectric constants between about 4900 and 5400, dissipation factors below about 2.0%, high insulation resistance capacitance products and stable temperature coefficient characteristics, by a process of mixing a major ceramic component with one or more precipitated dopant components. By controlling the conditions of the system, precipitated dopant particles are charged oppositely to major ceramic component particles and are thus associated with the major ceramic component particles.Type: GrantFiled: July 20, 1989Date of Patent: July 2, 1991Assignee: Tam Ceramics, Inc.Inventor: Terence C. Dean
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Patent number: 4939108Abstract: The present invention provides ceramic compositions for preparing multi-layer capacitors, having high dielectric constants between about 4900 and 5400, dissipation factors below about 2.0%, high insulation resistance capacitance products and stable temperature coefficient characteristics, by a process of mixing a major oxide component with one or more precipitated dopant components.Type: GrantFiled: November 2, 1988Date of Patent: July 3, 1990Assignee: TAM Ceramics, Inc.Inventor: Terrence C. Dean
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Patent number: 4882305Abstract: The present invention provides ceramic compositions for preparing multi-layer capacitors (MLCs) having high dielectric constants between about 3000 and 4700 and stable temperature coefficients (TC) prepared from high purity barium titanate, niobium pentoxide and cobalt oxide.Type: GrantFiled: October 9, 1987Date of Patent: November 21, 1989Assignee: TAM Ceramics, Inc.Inventors: Mike S. H. Chu, Charles E. Hodgkins, Terence C. Dean
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Patent number: 4840774Abstract: A process for the production of zirconium tetrachloride from dissociated zircon in which gaseous chlorine is passed through pellets consisting of ground dissociated zircon, carbon and a binder at a temperature in the range of from 450.degree. to 800.degree. C. The zirconium tetrachloride produced contains less than about 0.22% by weight, calculated as SiO.sub.2, of silicon tetrachloride.Type: GrantFiled: June 26, 1987Date of Patent: June 20, 1989Assignee: Tam Ceramics Inc.Inventors: John S. Campbell, Brian N. Baker, Anil Katyal
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Patent number: 4816430Abstract: Ceramic dielectric compositions having a dielectric constant of between about 3,000 to 4,000; dissipation factors of below about 1.8%, insulation resistance times capacitance products of about 10,000 ohm-farads at 25.degree. C. and above 1,000 ohm-farads at 125.degree. C. and stable temperature coefficient characteristics. In one embodiment, the dielectric constant of the present invention does not vary by more than .+-.15 percent over a temperature range of -55.degree. C. to 125.degree. C.Type: GrantFiled: June 9, 1987Date of Patent: March 28, 1989Assignee: Tam Ceramics, Inc.Inventor: Michael S. H. Chu
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Patent number: 4785375Abstract: The invention is directed to a dielectric ceramic having a dielectric constant K, greater than 35, a quality factor, Q, greater than 9,000 at 4 GH.sub.z and a reduction of the firing temperature to less than about 1350.degree. C. The dielectric ceramic consists essentially of a sintered mixture of about 35 to 55 mole percent ZrO.sub.2, about 30 to 50 mole percent TiO.sub.2, 5 to about 22.5 mole percent SnO.sub.2, about 0.5 to 10 mole percent ZnO, and 0.3 to about 2.5 mole percent CuO.Type: GrantFiled: June 11, 1987Date of Patent: November 15, 1988Assignee: Tam Ceramics, Inc.Inventor: Scott S. Campbell
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Patent number: 4780435Abstract: Ceramic dielectric compositions which have dielectric constants (K) of 60-140, dissipation factors (DF) of less than 0.1 percent, and temperature coefficient characteristics (TCC) of -20 ppm to -1000 ppm/.degree.C.Type: GrantFiled: April 15, 1987Date of Patent: October 25, 1988Assignee: TAM, Ceramics, Inc.Inventors: Michael S. H. Chu, Julie E. Carminati
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Patent number: 4757759Abstract: Printing device for the automated maufacture of multilayer capacitors and the like including an octagonal drum serving as a transport mechanism for rotating ceramic sheet around a horizontal rotational axis to apparatus for performing the various manufacturing process phases located at cardinal points around such axis, including apparatus for screening and stacking the printed sheets.Type: GrantFiled: March 5, 1986Date of Patent: July 19, 1988Assignee: Tam Ceramics, Inc.Inventor: Clarence L. Wallace
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Patent number: 4687044Abstract: A centrifugal injection machine comprises a rotor arm bearing at each of a pair of free ends a pivotably mounted container. A holder which retains a multiplicity of workpieces is insertable into a capsule or cavity within each container. The rotary arm contains a reservoir associated with each container or liquifying a charge of material. Upon rotation of the machine at a high velocity, the liquified material is transferred from the reservoir to the container in a vacuum and is pressurized therein as a result of centripetal acceleration. Upon the termination of a predetermined interval, a trip mechanism is activated to rotate the containers so that the molten liquid which has not been injected under pressure into recesses in the workpieces is ejected or discharged from the containers. The containers rotate within a vacuum chamber which is depressurized prior to the centrifuge operation.Type: GrantFiled: May 3, 1985Date of Patent: August 18, 1987Assignee: Tam Ceramics, Inc.Inventor: Clarence L. Wallace
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Patent number: 4612600Abstract: This invention discloses multilayer capacitors having base metal electrodes sintered at temperatures less than about 950.degree. C. with a lithium fluoride flux, and having a base metal oxide integument at the surface of the electrodes, as well as, a method for making such electrodes with dielectric compositions containing lithium fluoride flux and by adjusting the PO.sub.2 in the sintering atmosphere to avoid oxidation of the base metal and reduction of the metal oxides in the dielectric ceramic.Type: GrantFiled: October 29, 1984Date of Patent: September 16, 1986Assignee: TAM Ceramics Inc.Inventor: Charles E. Hodgkins
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Patent number: 4506026Abstract: A low fired, temperature compensating dielectric composition is disclosed. The invention dielectric is formed of a base ceramic and a frit material. The base ceramic includes magnesium oxide, titanium oxide, calcium oxide, alumina, silica and at least one oxide of a rare element from the group of niobium, neodymium, tantalum, lanthanum, yttrium and praseodymium. The preferred oxides are those of niobium alone or with neodymium.Type: GrantFiled: December 23, 1983Date of Patent: March 19, 1985Assignee: TAM Ceramics, Inc.Inventors: Charles E. Hodgkins, Daniel C. Rose, Dana L. Coller
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Patent number: 4353957Abstract: Monolithic capacitors are produced by (1) providing on a plurality of thin leaves or sheets of suitable finely divided ceramic material bonded with a thermally-fugitive temporary bond, coatings comprising thin, selected patterns of pseudo-conductive material that consists essentially of thermally-fugitive material, one or more ceramic or metal granules, and a thermally-fugitive bond; (2) forming a consolidated stack from a plurality of the coated leaves or sheets; (3) firing the resulting body to remove the thermally-fugitive materials and sinter the ceramic material into a monolithic body in which there are thin cavities or open spaces which are interrupted only by one or more distinct ceramic or metal pillars, substantially all of which, when there are a plurality, are distinct and separated; (4) introducing conductive material, preferably metal, into the resulting cavities; and (5) providing suitable electrical connections to the resulting conductive layers.Type: GrantFiled: October 26, 1977Date of Patent: October 12, 1982Assignee: Tam Ceramics Inc.Inventors: Truman C. Rutt, James A. Stynes
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Patent number: 4335216Abstract: Low temperature fired dielectric ceramic compositions are prepared by firing, at temperatures between about 1000.degree. C. and about 1150.degree. C., a base ceramic preparation comprising barium titanate, strontium titanate, barium zirconate, titanium dioxide and manganese dioxide mixed with a glass frit comprising zinc oxide, silicon dioxide, boron oxide, lead oxide, bismuth tioxide, and cadmium oxide. The resulting dielectric ceramic composition is useful to form multilayer ceramic capacitors.Type: GrantFiled: May 1, 1981Date of Patent: June 15, 1982Assignee: TAM Ceramics, Inc.Inventors: Charles E. Hodgkins, Mark J. Giermek