(1 -) X Cacu < Sub > 3 < / Sub > Ti < Sub > 4 < / Sub > O < Sub > 12 < / Sub > - Xatio < Sub > 3 < / Sub > Base Preparation And The Giant Dielectric Properties Of The Ceramic Research

With the development trend of electronic device miniaturization and high speed has become increasingly evident, the high dielectric constant material CaCu3Ti4O12(CCTO) has attracted much attention because of its potential applications in the high dielectric constant capacitors, dynamic random access memory and other high-tech fields. As a candidate material for electronic components, CCTO materials should have a high dielectric constant and low dielectric loss. It is widely accepted that an internal barrier layer capacitance (IBLC) model is more suitable to explain the dielectric behaviors. The model indicates that CCTO is the inhomogeneous consisting of semiconducting grains and insulating grain boundaries. The way of improving the dielectric properties of CCTO ceramics is to reduce the grain resistance or increase the resistance of the grain boundary.In this paper, the phase structure, microstructure and dielectric properties of (1-x)CCTO-xATiO3(A=Ca2+Sr2+, Ba2-) ceramics prepared under different conditions and the contents of CaTiO3, SrTiO3, BaTiO3were studied to accommodate the high dielectric constant.1. study the effect of different conditions on dielectric properties of (1-x)CCTO-xCaTiO3ceramics, the results showed that the samples were calcined at920℃and sintered at1060℃, the0.90CCTO-0.10CTO ceramics had a pure perovskite structure, clearer grain boundary, higher density and huger dielectric constant. The0.90CCTO-0.10CTO ceramics exhibited good dielectric properties as follows:εr=91441, tanδ=0.063at10kHz. The Complex impedance results revealed that the grain was semiconducting and the grain boundaries was insulating, the higher permittivity can be explain by the internal barrier layer capacitance (IBLC) model. The grain resistance Rg was2567Q-cm-1, and the grain boundary resistance Rgb was3.96x104Ω·cm-1.2. The phase structure, microstructure and dielectric properties of (1-x)CCTO-xBaTiO3ceramics as a function of the BaTiO3content and sintering temperature were investigated. The results indicated that when the samples were calcined at940℃and sintered at1060℃, the0.95CCTO-0.05BTO ceramics had clearer grain boundary. With increasing of the BaTiO3content, the dielectric properties became worse, the (1-x)CCTO-xBaTiO3had lower dielectric constant and higher dielectric loss compared with those of CCTO. A small amount of BaTiO3ceramics basically maintain a good temperature stability. When BaTiO3content is0.10, the dielectric constant and temperature stability of the ceramic reduce dramatically.3. The effect of SrTiO3content on the phase structure, microstructure and dielectric properties of (1-x)CCTO-xSrTiO3ceramics were discussed. It was found when the samples were calcined at 940℃and sintered at1040℃, the0.95CCTO-0.05STO ceramics exhibited good dielectric properties as follows:10kHz下εr=109097, tanδ=0.078. In addition, the sintered ceramic have huge dielectric constant at room temperature in the40Hz-105Hz frequency range, the dielectric constant are more than6.0x104. Compared wiith the CaCu3Ti4O12ceramics, the dielectric constant of the0.95CCTO-0.05STO increase by35225. The Complex impedance results revealed that the grain was semiconducting and the grain boundaries was insulating., the grain resistance Rg was1275Ω·cm-1and the grain boundary resistance Rgb was4.68×104Ω·cm-1.4. The effect of ATiO3on the preparation technology, dielectric properties of (1-x)CCTO-xATiO3(A=Ca2+, Sr2+, Ba2+) ceramics were discussed. It was found that the (1-x)CCTO-xATiO3(A=Ca2-, Sr2+, Ba2+) ceramics have the similar preparation technology. while the addition BaTiO3reduce the dielectric properties, the dielectric constant of the0.90CCTO-0.10CTO,0.95CCTO-0.05STO ceramics significantly improved. Compared wiith the CaCu3Ti412ceramics, the dielectric constant of the0.90CCTO-0.10CTO,0.95CCTO-0.05STO increase by17569,35225.