| With the development of technology and the society, the material, information and energy resources have become the important thing in modern life. As the mater carrier of scientific and technical payoffs as well as innovation, materials has been facing new challenge and demand, especially in the fast development world. So we choose electronic ceramics material as the research subject of this thesis. Electro-mechanical coupling effect is the index of scaling materials. Because of the preferably piezoelectric and electrostriction properties of Pb(Zr,Ti)O3and Pb(Mg,Nb)O3, it take up the leading role. Because the lead will be the pollution of the environment and will be impossible to deal with, the BNT was chosen as the lead-free piezoelectric ceramics.(Bio.5Na0.5)Ti03has stronger ferroelectric property and higher Curie temperature, but it has large coercive field and small electrostriction. One purpose of studding this material is decreasing its coercive field and analyzing the relaxation mechanism. In this work, we further investigated the relaxation and electric field inducement strain properties, which provide reference and gist for manufacturing micro positioner and arrester.BNKT2—xBCT and (BNT-BZTl)+xwt%Sb2O3ceramic were prepared by conventional solid state reaction method. In this work, we studied the sintering behavior, structure, microstructure, ferroelectric, dielectric and strain properties of ferroelectric ceramics with adding BCT and Sb2O3. We also analyzed the relation of property with structure and constitution.(1)(1-x)[0.8Nao.5Bio.5Ti03-0.2ko.5Bio.5Ti03]-xBao.7Cao.3Ti03ceramic: the XRD pattern confirms the formation of pure perovskite structure, which indicates that the BCT has been totally in the crystal lattice. The sample x=0.04to x=0.08are in the transition region of phase shift, which shifting from tetragonal structure to pseudo cubic structure. It can be seen little pore from the SEM patterns and the grain size becomes small and gets some changes with increasing BCT. It comes up the property of relaxation ferroelectric. When x=0.08, y comes to1.94. The ferroelectric hysteresis indicates that the addition of BCT strongly weaken the ferroelectric property. Pr decreases from31μC/cm2to9μC/cm2. Coercive field decreases from3.55kV/mm to1.2kV/mm. The stain comes to the maximum (0.122%) at phase transition region.(2)[0.9(Bio.5Nao.5)Ti03-0.1Ba(Tio.95Zro.o5)03]+x wt%Sb2O3ceramic:XRD pattern confirmed the formation of pure phase without coming the second phase. Densification ceramics were seen from the SEM patterns. The grain size over grow up in the high adulterate component. The dielectric property indicates that (BNT-BZTl)+xwt%Sb2O3ceramics are relaxation ferroelectric (y>1.8), which can ameliorate the dielectric temperature stability of materials. Ferroelectric hysteresis indicates that this material has great effect to ferroelectric. Because of the effect of out of order ion and changing valence of Sb ion, ferroelectric domains stability gets lower making the ferroelectric property gets weaker. The adulteration of Sb ion makes the inverse piezoelectric effect noneffective. The strain capacity decreases with increasing the adulteration. |
PDF Full Text Request