Preparation, Microstructure And Properties Of BaTiO₃Based Ceramics And Thin Film

In this paper, a series of (1-x)[BaTi0.8Zr0.2O3]-x[Ba0.7Ca0.3TiO3](BZT-BCT) nano-powder have been successfully prepared by sol-gel method. BZT-BCT dense bulk was obtained by the two step sintering and conventional sintering method respectively. Well, the nano-films were obtained on Si and Ti by sol-gel method. Microstructure and electrical properties have been measured, as well, the investigations on the electrical properties of BZT-BCT ceramics have been comprehensively and systemically conducted.The analysis of high resolution XRD revealed that:the structure was typical perovskite in lower sintering temperature, indirectly demonstrated sol-gel process need lower temperature than solid reaction process. The composition of Zr is decreasing with the increasing of x, it caused the reduction of interplanar crystal spacing, so we see diffraction peak the tendency of moving towards high angle. When x=0.3, XRD of ceramics revealed that in45°and65°, the splitting peaks were very obvious, and the splitting peaks proved it was mainly tetragonal.SEM images indicated:with the increase of x, the sintering temperature of powder is decreasing; ceramic grain size is very small and dense by two step sintering method. Additionally, we see that the grain size is growing observably after1350℃.The electric properties on x=0.3(near the morphortropic phase boundary) ceramics of BZT-BCT, it possessed the best ferroelectric and piezoelectric properties, d33can reach to530pm/V. Meanwhile, round this composition, we also got high d33, but far from the morphortropic phase boundary, it was opposite, this result also been proved theoretically. The energy loss density is increasing linear dependent on applied field; the energy loss density is becoming lower and then stable when the temperature increasing. The maximum permittivity can reach to24600, the dielectric loss is lower than0.03at room temperature. Dispersion index γ is increasing dependent on the growing of frequency, it was1.64at1Hz and1.80at100Hz. The analysis of Nanocrystalline BaTiO3ceramics, Pr and Ec were decreasing dependent on the growing temperature. For Nanocrystalline BaTiO3ceramics, the frozen domain structure under an external field owing to the effects exerted by the grain boundaries and the depolarization field originated by the low permittivity nonferroelectric grain boundaries play significant influence in the suppression of ferroelectric hysteresis and domain switching.The results of electrical properties showed that the film of BaTiO3obtained on Ti slice was superior to Si, the leakage can down to8.09×10-4A/cm2, Pr was7.65μC/cn2, and permittivity can reach to820at room temperature.