BaTiO_(3)基无铅陶瓷介电温度稳定性研究

Dielectric Temperature Stability of BaTiO_(3)-based Lead-free Ceramic

通过固相合成法制备了xBi(Zn,Zr)O_(3)-(1-x)(Ba,Ca)(Ti,Zr)O_(3)(BCTZ-xBZZ,x=0,0.005,0.02,0.04,0.06)无铅陶瓷体系,结合X射线衍射(XRD)、扫描电镜(SEM)、介电等表征,探讨了Bi(Zn,Zr)O_(3)陶瓷体系对(Ba,Ca)(Ti,Zr)O_(3)陶瓷的晶相、微结构、介电以及其温度稳定性的影响。研究结果表明:当预烧温度高于850℃时BCTZ-xBZZ合成粉体已基本形成单一的钙钛矿结构。在较低的烧结温度(1200~1300℃)下BCTZ-xBZZ陶瓷可以很好地烧结。所有BCTZ-xBZZ陶瓷都具有纯钙钛矿相,与此同时,陶瓷体系晶相经历了从四方晶相向伪立方相过渡。Bi(Zn_(0.5)Zr_(0.5))O_(3)显著影响了(Ba,Ca)(Ti,Zr)O_(3)陶瓷体系相变温度:铁电相-铁电相(T_(FE)),铁电相-顺电相(T_(c))。并且陶瓷体系存在弛豫行为,在高温范围内,修正的居里外斯定律1/ε_(r)-1/ε_(r,m)=C(T-T_(m))^(α)可以很好地用来解释Bi(Zn_(0.5)Zr_(0.5))O_(3)-(Ba_(0.98)Ca_(0.02))(Ti_(0.95)Zr_(0.05))O_(3)陶瓷体系的介电弛豫性。这归因于在A位和B位中无序性离子的共同作用。此外,陶瓷体系0.96(Ba_(0.98)Ca_(0.02))(Ti_(0.95)Zr_(0.05))O_(3)-0.04Bi(Zn_(0.5)Zr_(0.5))O_(3)在-25~135℃温度范围中,具有较稳定的电容温度系数(大约在±15%)和低的介电损耗(<0.1)。这表明该陶瓷在电容器中具有潜在的应用。

xBi(Zn,Zr)O_(3)-(1-x)(Ba,Ca)(Ti,Zr)O_(3)(BCTZ-xBZZ,x=0,0.005,0.02,0.04,0.06)lead-free ceramics have been prepared by the conventional ceramic process.The influence of Bi(Zn,Zr)O_(3) on structure and dielectric temperature stability of(Ba,Ca)(Ti,Zr)O_(3) ceramics were systematically studied by use of XRD,SEM,dielectric measurement.The results indicate that when the calcination temperatures are higher than 850 ℃,the BCTZ-xBZZ powders have basically formed a single perovskite structure.The ceramics are well sintered at a relatively low temperatures(1200~1300℃)by doping with Bi(Zn,Zr)O_(3).All BCTZ-xBZZ ceramics possess pure single phase of perovskite structure,and the ceramics transfer from T phase to Pc phase.The ferroelectric-ferroelectric phase transition temperatures(T_(FE))and ferroelectric-paraelectric phase transition temperatures(T_(c))of BCTZ ceramics are significantly affected by the addition of BZZ.Temperature dependence of the dielectric properties indicates that as the concentration of BZZ increases,the BCTZxBzz solid solution ceramics exhibit more relaxor-like behavior.The thermal variation of the relative permittivity is well explained by the modified law 1/ε_(r)-1/ε_(r,m)=C(T-T_(m))^(α)in the high temperature range.The relaxor behavior for Bi(Zn_(0.5)Zr_(0.5))O_(3)-(Ba_(0.98)Ca_(0.02))(Ti_(0.95)Zr_(0.05))O_(3) ceramics is ascribed to the combination of cation disorder from A-sites and B-sites.In addition,the 0.96(Ba_(0.98)Ca_(0.02))(Ti_(0.95)Zr_(0.05))O_(3)-xBi(Zn_(0.5)Zr_(0.5))O,ceramics(x=0.04)has a stable temperature coefficient of capacitance(±15%)and low dielectric loss(<0.1)in the temperature range of-25~135℃,which demonstrates that the BCZT-xBZZ ceramics have a latent utilization in ceramic capacitors.