Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological chang...Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological changes on dielectric and ferroelectric properties in lead-free BCZT ceramics,researchers have mostly focused on the influence of spherical grain shape change.In this study,BCZT ceramics with rod-like grains and aspect ratio of about 10 were synthesized by surfactant-assisted solvothermal route.X-ray diffraction(XRD)and selected area electron diffraction(SAED)performed at room temperature confirm the crystallization of pure perovskite with tetragonal symmetry.Scanning electron microscopy(SEM)image showed that BCZT ceramics have kept the 1D rod-like grains with an average aspect ratio of about 4.Rod-like BCZT ceramics exhibit enhanced dielectric ferroelectric(εr=11,906,tanδ=0.014,Pr=6.01μC/cm^2,and Ec=2.46 kV/cm),and electrocaloric properties(ΔT=0.492 K andz=0.289(K×mm)/kV at 17 kV/cm)with respect to spherical BCZT ceramics.Therefore,rod-like BCZT lead-free ceramics have good potential to be used in solid-state refrigeration technology.展开更多
文摘选取传统高温固相反应合成法制备出Bi_2O_3掺杂的无铅压电陶瓷材料Ba_(0.85)Ca_(0.15)Zr_(0.08)Ti_(0.92)O_3-xBi_2O_3(BCZT-x Bi,x=0~0.15)。采用扫描电子显微镜、准静态压电常数测试仪等一系列检测手段,探讨了Bi_2O_3掺杂对BCZT基无铅压电陶瓷微观组织和电学性能产生的作用,从SEM图像得知,陶瓷的晶粒尺寸随着Bi_2O_3掺杂量的增多先逐渐变小后略微有所增大,XRD图谱则表明,掺杂量不等的Bi^(3+)均能够弥散进入钛酸钡晶格中,能完整固溶于BCZT陶瓷,并且材料具有典型的钙钛矿相结构。当Bi_2O_3掺杂量为0.15 mol%时,此无铅压电陶瓷材料拥有较好的介电性能,介电损耗tanδ的值仅是1.2%,介电常数ε_r的值是5100;当没有掺杂Bi_2O_3时,此陶瓷的压电性能最优,压电系数的值d_(33)=386 p C/N,机电耦合系数的值K_p=44.8%。
基金The authors gratefully acknowledge the generous financial support of CNRST Priority Program(PPR 15/2015)Slovenian Research Agency Program(P1-0125)European Union’s Horizon 2020 Research and Innovation Program under the Marie Skłodowska-Curie Grant Agreement(No.778072).
文摘Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological changes on dielectric and ferroelectric properties in lead-free BCZT ceramics,researchers have mostly focused on the influence of spherical grain shape change.In this study,BCZT ceramics with rod-like grains and aspect ratio of about 10 were synthesized by surfactant-assisted solvothermal route.X-ray diffraction(XRD)and selected area electron diffraction(SAED)performed at room temperature confirm the crystallization of pure perovskite with tetragonal symmetry.Scanning electron microscopy(SEM)image showed that BCZT ceramics have kept the 1D rod-like grains with an average aspect ratio of about 4.Rod-like BCZT ceramics exhibit enhanced dielectric ferroelectric(εr=11,906,tanδ=0.014,Pr=6.01μC/cm^2,and Ec=2.46 kV/cm),and electrocaloric properties(ΔT=0.492 K andz=0.289(K×mm)/kV at 17 kV/cm)with respect to spherical BCZT ceramics.Therefore,rod-like BCZT lead-free ceramics have good potential to be used in solid-state refrigeration technology.
