Properties Of BZTO Based Ceramics Modified With Y

Barium titanate dielectric ceramics containing BaTiO₃ or BaTiO₃ solid solutions as major crystal phase have high dielectric constant ,good Ferroelectric, piezoelectric , oltage-resistant, insulation capabilities, Barium-titanate ceramics,which have been developed in several decades years, are one of the most important functional ceramics and used as one kind of the most important materials in capacitor manufacturing. And they have found extensive application in many fields such as electroics, calorifics, optics. The research of preparation and properties of barium-titanate has been a focal point in the field of inorganic solid chemistry since the excellent dielectric properties of barium-titanate were discovered in 1940s. However, the research of barium-titanate was began only in recent years in our country and there is a lot of work to do.Barium titanate is a kind compound of simple perovskite lattice. But the compound existing as monocase has large dielectric loss, making it unable to meet the request of application.So frequently it is used in solid solution or by adding impurity to improve its dielectric capacity. And that is why there are more researches to complex perovskite lattice. Currently the capacity improvement to compounds of complex perovskite lattice are focusing on incorporation in both A-sites and B-sites ,choosing high active raw materials and the applications of wet chemical method.On the basis of the former research ,this dissertation is researching on how to add some Zr element and rare-earth element Y to improve the dielectric constant and lower dielectric loss. And at the same time Curie Temperature is lowered, that is the Curie peak of dielectric constant is moved to low temperature. So the dielectric capacity is improved totally. And some contribution was made to expand the application of Barium titanate dielectric ceramics.In this paper, BZTO based ceramics modified with Y were prepared by solid-state method. The powders and ceramics were characterized by XRD and SEM. The dielectric properties of the ceramics were determined.In general,the main work is as follows:A The preparation and dielectric properties of BZTO based ceramics: BZTO powders had been synthesized by solid-state process from BaCO₃,TiO₂ and ZrO₂ and were characterized by XRD. The influence of Zr content and calcined temperature had been studied. The results were: when Zr content x=0.25, and calcined temperature was 1300℃/2h,the properties of the powders were good.B The preparation and dielectric properties of BZTO based ceramics modified with Y: With the addition of Y₂O₃ , the Tc shifted to higher temperature and then to lower temperature, the dielectric constant unchanged firstly and then decreased with the increasing of the amount of Y at room temperature.