Study Of The Series Ceramic Phase, Structure And The Dielectric Properties Of ZnO,La₂O₃/Gd₂O₃Composite Doping Ba_0.2Sr_0.8TiO₃

As development of the materials science and technology, barium strontium titanate (Ba1-xSrxTiO3)ceramic materials get more and more the attention of the countries all over the world and researchers. Thisis because barium strontium titanate (Ba1-xSrxTiO3) ceramic material is a good thermal materials, capacitormaterials and iron voltage electrical material, has many excellent dielectric performance. Barium strontiumtitanate ceramics doped with modified, can not only make the material performance optimization, and alsoto discover new materials.This paper using solid phase reaction process, prepared ZnO (the mole ratio is0.03864) andLa2O3/Gd2O3(the mole ratio is X=0.00,0.04,0.05,0.06) composite doping barium strontium titanate(Ba0.2Sr0.8TiO3) series ceramic samples. Using scanning electron micro-scope, X-ray diffraction analysisand dielectric spectrum method to make the representation and analysis research for the surface ofmorphology and physical phase structure and dielectric proproperties of ceramic samples.(1) For ZnO、La2O3composite doping Ba0.2Sr0.8TiO3series ceramic samples, the analysis results showthat:1) the series ceramic sample are mainly composed of crystal sizes being430~1222and single crystalstructure of BST and interstitial;2) The grain size reduced with La2O3mixed, and changed crystal structureof the samples (From cubic crystal of X=0.00to orthogonal crystal sysmtem of X=0.04,0.05,0.06); At thesame time crystal cell volume changed;3)At the same sintering temperature (1340C), ZnO、La2O3composite doping can improve the surface diffusion coefficient of the materials, and increase surfacediffusion rate, and restrain the densification of ceramic material structure, and promote grain growth. Whendoping quantity is0.04, grain reunion is more serious, crystallization degree is poor, with the increasedamount of doping, ceramic grain size becomed small at first and than changed big, the grain of X=0.06isdistributed uniformity and good dispersion, and the good crystallization degree;4)When mixed with La2O3,grain size of samples was decreasing, and crystal symmetry changed, the dielectric constant and dielectricloss was also changed, namely the dielectric properties of samples were had a certain influence by thecrystal structure and the amount of La2O3. By analyzing, the place is at f=103Hz, T=300K, as dopingquantity with X=0.06, dielectric constant of samples is moderate, and in low frequency dielectric losssignificantly reduced, and it changed not big in the high frequency (103Hz) period.(2) For ZnO、Gd2O3composite doping Ba0.2Sr0.8TiO3series ceramic samples, the analysis results showthat:1) the series ceramic sample are mainly composed of crystal sizes being441-1222and single crystalstructure of BST and interstitial;2) The grain size reduced with Gd2O3mixed, and changed crystal structureof the samples (From cubic crystal of X=0.00、0.04to tetragonal crystal sysmtem of X=0.05,0.06); At thesame time crystal cell volume changed;3) ZnO、Gd2O3composite doping Ba0.2Sr0.8TiO3can promote grain growth and restrain the densification of ceramic material structure, with the increased amount of doping,ceramic grain size becomed small at first and than changed big, and porosity content increased, the grain ofX=0.06is distributed uniformity and good dispersion, and the good crystallization degree, and showingsquare column shape;4) When mixed with Gd2O3, grain size of samples was decreasing, and crystalsymmetry changed, the dielectric constant and dielectric loss was also changed, namely the dielectricproperties of samples were had a certain influence by the crystal structure and the amount of Gd2O3. Byanalyzing, the place is at f=103Hz, T=300K, as doping quantity with X=0.06, dielectric constant anddielectric loss of its frequency stability is good, and the dielectric loss is the least.