EFFECT OF ATMOSPHERE ON DIELECTRIC PROPERTIES OF CALCIUM COPPER TITANATE CERAMICS

摘要

The stability and reproducibility of dielectric properties displayed by calcium copper titanate (CCTO) ceramics can be of concern when they are used as capacitor dielectrics and energy storage applications.Highly irreproducible dielectric properties were observed for samples tested in ambient conditions suggesting that ambient played an important role on the stability of dielectric properties.Consequently,the effects of various atmospheric conditions such as air,moisture,and inertness of the atmosphere on dielectric properties were studied on dense and phase pure CCTO samples prepared by powder processing and sintering.Stable and reproducible impedance data were successfully achieved by testing the samples in dry N2.Especially,low frequency dielectric properties were gready enhanced in dry ambient than in humid air.This new approach of characterizing dielectric properties of CCTO can be used to eliminate hysteresis due to ambient atmosphere and produce stable and reproducible properties.These results will be presented and discussed.