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PROPERTIES OF BARIUM‐STRONTIUM TITANATE DIELECTRICS*
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1947
Year
Materials ScienceNuclear CeramicDielectric ConstantHigh Temperature MaterialsEngineeringFerroelectric ApplicationEnergy CeramicApplied PhysicsFerroelectric MaterialsCeramics MaterialsBarium‐strontium TitanatesRadioanalytical ChemistryNuclear MaterialsThermodynamicsRadio EquipmentElectrical PropertiesNuclear Reactors
A bstract The results on barium‐strontium titanates are given for heat‐treatment, absorption, shrinkage, thermal expansion, dielectric constant, K , at minus 60° to 85°C. and also for Q (the reciprocal of the power factor) at 25°C. for frequencies of 50 kc. per sec. to 20 mc. per sec. A few measurements of K and Q were made at 3000 mc. per sec. Specimens with an absorption of less than 0.l% matured at 1250° to 1430°C. K values ranged from 34 for BaO:4TiO 2 to several thousand for specimens with compositions on the BaTiO 3 ‐SrTiO 3 join. The BaO: 5TiO 2 specimens were unique in that their temperature coefficient of K was practically zero. O values ranged from 50 to 100 for test pieces containing more than 40% of BaO and from 400 to 10,000 for those with less than 40% of BaO. K values did not change appreciably with frequency. Linear thermal expansions (between 25° and 700°C.) ranged from 0.6 to 0.84%. Many of these specimens could be used in radio equipment.