Sb5+取代BNT基弛豫铁电体的性能研究

Study on the Properties of Sb Substituted BNT Based Relaxor Ferroelectrics

利用传统固相法制备了0.6[(1-x)(Bi0.5Na0.5)TiO3-xNaSbO3]-0.4(Sr0.7Bi0.2)TiO3陶瓷材料(缩写为BNT-NSO-SBT-x),其中x=0.04 mol,0.06 mol,0.08 mol和0.1 mol。研究了引入第三组元NaSbO3后对BNT-NSO-SBT-x陶瓷相结构、介电和铁电性能以及储能特性的影响。Sb^5+对相结构并未造成显著影响,BNT-NSO-SBT-x陶瓷在室温具有三方和四方共存相。BNT-NSO-SBT-x陶瓷为呈现典型弥散特征的弛豫铁电体(γ~2),这源于A、B位离子复合占位而引起的成分不均一,以及三方和四方PNRs共存造成的结构不均一。Sb^5+取代量增大时,Tp和Tm逐渐靠近;由于Tp(<80℃)靠近室温,引起弱极性四方相PNRs增多,使得陶瓷的铁电性能恶化,但却有利于提高储能特性。x=0.06时BNT-NSO-SBT-x陶瓷的储能较优,W1=0.227 J/cm^3,η=76.2%(E=40 kV/cm,f=10 Hz)。

0.6[(1-x)(Bi0.5Na0.5)TiO3-xNaSbO3]-0.4(Sr0.7Bi0.2)TiO3 ceramics(abbreviated as BNT-NSO-SBT-x) was prepared by the conventional solid state reaction method, where x=0.04 mol, 0.06 mol, 0.08 mol and 0.1 mol. The effects of the third component NaSbO3 on the phase structure, dielectric and ferroelectric properties, and energy storage properties of BNT-NSO-SBT-x ceramics were studied. Sb^5+ has no significant effect on the phase structure, and BNT-NSO-SBT-x ceramics have a coexistence phase structure of rhombohedral and tetragonal at room temperature. BNT-NSO-SBT-x ceramics are relaxor ferroelectrics with typical dispersion characteristics(γ~ 2). This is due to the inhomogeneous composition caused by complex cation occupation in A and B-site, and the inhomogeneous structure caused by the coexistence of rhombohedral and tetragonal PNRS. When the substitution amount of Sb^5+ increases, Tp and Tm gradually approach. Because the Tp(<80 ℃) closes to room temperature, the weak polar tetragonal PNRs enhance. It deteriorates the ferroelectric performance of the ceramic, but it’s beneficial to improve the energy storage characteristics. The energy storage of BNT-NSO-SBT-x ceramics with x=0.06 is better, W1=0.227 J/cm^3, η=76.2%(E=40 kV/cm, f=10 Hz).