Tam Ceramics, Inc.

Charles E Hodgkins

Mike S-h Chu

Daniel C Rose

Terence C Dean

Mark J Giermek

Dana L Coller

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.

Dielectric ceramic composition with high dielectric constant and flat TC

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.

Low fire ceramic compositions

A low temperature fired ceramic dielectric composition in which the dielectric constant does not vary from its base value of over 2400 by more than 15 percent over a wide temperature range. A base ceramic preparation (a) and a ceramic flux (b), each consisting essentially of metal oxides or precursors thereof to provide in oxide form (a) 98.0 to 99 weight percent barium titanate, from about 0.97 to about 1.54 weight percent niobium pentoxide and from about 0.19 to about 0.32 weight percent cobalt oxide; (b) from about 16 to about 60 weight percent bismuth titanate, about 8 to about 52 weight percent lead titanate, about 18 to about 35 weight percent zinc oxide and about 5 to about 11 weight percent boron oxide. Manganese dioxide or precursor thereof in amount of from about 0 to 0.114 percent of the combined weight of the base ceramic preparation and ceramic flux is added to the metal oxides or precursors of the base ceramic preparation and ceramic flux and the mixture is fired at a temperature less than about 1150.degree. C.

Low temperature fired dielectric ceramic composition with flat TC

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.

Low firing ceramic dielectric for temperature compensating capacitors

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.

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Lewiston, NY, United States of America

Charles E Hodgkins