Cookson Group Plc

Tam Ceramics, Inc.

Michael Rand

Christopher Hood

John Bultitude

Kay Louise Nimmo

Mike Ssu-Hai Chu

Ian Thompson

Mike Ssu Chu

Barium titanate temperature stable dielectric compositions are disclosed containing magnesium oxide, silicon dioxide, germanium oxide and optionally an oxide or carbonate of barium, calcium or strontium which can be used to produce multilayer ceramic capacitors with nickel or nickel alloy electrode that have a variation of capacitance with temperature of less than .+-.10% over the range -55.degree. C. to +125.degree. C. compared with the value of the capacitance at 25.degree. C., or to produce multilayer ceramic capacitors with noble metal inner electrodes that have a variation of capacitance with temperature of less than .+-.15% over the range 55.degree. to +125.degree. C. compared with the value at 25.degree. C., and which does not contain any second phases after sintering.

Temperature stable dielectric

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.

Dielectric stable at high temperature

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Witney, United Kingdom

Michael Rand