Japanese Journal of Applied Physics · 1977 · 33 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsCeramicsMaterials PhysicsConductive MaterialsElectrical ConductivityFerroelectric CeramicsFerroelectric MaterialsPiezoelectric CeramicsPiezoelectric MaterialsConductionPiezoelectric EffectPiezoelectric PropertiesPiezoelectricityRelaxation PhenomenaRelaxation Time MeasurementsRelaxation TimesTemperature Dependence
The complex piezoelectric constant d=d'-id'' was measured for composite epoxy resin and PZT ceramics at temperatures between 110°C and 160°C in the frequency range from 0.03 to 30 Hz. A remarkable relaxation was observed above 140°C: d' increased with decreasing frequency and d'' showed a peak. This relaxation is ascribed to the d.c. conduction of ionic impurities activated at high temperatures in epoxy phase, because d'' maximum frequency snowed the same temperature dependence as the conductivity. The values of the relaxation time and the relaxation strength were discussed on the basis or a theoretical expression of the piezo-electric constant for a two phase system with spherical piezoelectric inclusions.