Study On Ferroelectric Properties Of BaTiO₃ Ceramics

Ions with different valence and radius are doped at B site of Ba(Ti0.91Zr0.09)O3 base ceramics which are the perovskite structure. The Ba(Ti0.91Zr0.09)O3 base ceramics are prepared by traditional solid phase reaction. Sintering characteristic, phase transition, ferroelectric and piezoelectric properties of Ba(Ti0.91Zr0.09)O3 base ceramics doped with additive have been investigated1.The influence of doped with the different radii(Co3+,Sb3+) ions on structure and properties has been studied. XRD results show that the ions have entered into the lattice. With increasing of the content of doped additives, the crystallite size for Ba(Ti0.91Zr0.09)O3 ceramic becomes smaller and more homogeneous, and the phase diffusion appears obviously. The diffuse phase transition is explained by the composition fluctuate theory. The results also show that the density and the dielectric properties of ceramics are related to the crystallite size. The hysteresis loop also changes after doping. Both the coervice field Ec and the remanent polarization Pr decrease.2.On the basis of fixing content of Al3+ codoping inequal radii(Nb5+,V5+) ions, the influence on structure and properties of Ba(Ti0.91Zr0.09)O3 has been studied. The research results show that there is liquid phase generated during codoped sintering of V2O5 and the liquid phase can accelerate the course of sintering. The Ba(Ti0.91Zr0.09)O3 ceramics presents common ferroelectric characteristic. But after Al-Nb doped, obvious diffusing phenomenon can be observed.3. The influence of equivalent compensation charge (Co3+ and V5+ , Sb3+ and Nb5+ , Co3+ and Nb5+) codoped at B site on structure and properties of Ba(Ti0.91Zr0.09)O3 ceramic has been studied. The results of XRD show that the codoped ions have entered into the crystal lattice and have made the diffraction peak move. What's more, the second phase also appears in the ceramics. After the codoping of equivalent compensation charge, it's easier for the dielectric peak to widen, and all present dispersion characteristics. The sintering temperature is reduced when the Co3+and V5+ codoped for liquid sintering. Relaxation phenomenon can be obviously observed when Sb3+and Nb5+ are codoped. The relaxation phenomenon can be explained by the random electric field caused by dipole.