采用传统的固相反应法制备了(Ba_(0.85)Ca_(0.15))(Ti_(0.9)Zr_(0.1))O_(3)(BCZT)以及掺杂Al-Mg-Ca玻璃粉的BCZT无铅压电陶瓷。首先研究了预烧温度对BCZT陶瓷粉体的影响,其次研究了掺杂Al-Mg-Ca玻璃粉对BCZT无铅压电陶瓷的烧结性能、介...采用传统的固相反应法制备了(Ba_(0.85)Ca_(0.15))(Ti_(0.9)Zr_(0.1))O_(3)(BCZT)以及掺杂Al-Mg-Ca玻璃粉的BCZT无铅压电陶瓷。首先研究了预烧温度对BCZT陶瓷粉体的影响,其次研究了掺杂Al-Mg-Ca玻璃粉对BCZT无铅压电陶瓷的烧结性能、介电性能和压电性能的影响。最后通过正交试验确定了其烧结工艺。结果显示BCZT粉体的最佳预烧温度在1100℃。掺杂Al-Mg-Ca玻璃粉能够有效降低BCZT陶瓷的烧结温度。通过烧结工艺正交实验获得了最佳烧结工艺:1100℃预烧,1350℃烧结,升温速度为2℃/min,保温时间为7 h,在110 min降温至800℃。验证正交试验所得到的结果是掺杂Al-Mg-Ca玻璃粉的BCZT陶瓷的居里温度点的介电常数为12228,压电常数d_(33)为425 p C/N。展开更多
Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively...Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.展开更多
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
The intrinsic conduction mechanism and optimal sintering atmosphere of(Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_(3)(BCZT)ceramics were regulated by Mn-doping element in this work.By Hall and impedance analysis,the undop...The intrinsic conduction mechanism and optimal sintering atmosphere of(Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_(3)(BCZT)ceramics were regulated by Mn-doping element in this work.By Hall and impedance analysis,the undoped BCZT ceramics exhibit a typical n-type conduction mechanism,and the electron concentration decreases with the increasing oxygen partial pressure.Therefore,the undoped ceramics exhibit best electrical properties(piezoelectrical constant<733=585 pC·N^(-1),electro-mechanical coupling factor k_(p)=56%)in O_(2).A handful of Mn-doping element would transfer the conduction mechanism from n-type into p-type.And the hole concentration reduces with the decreasing oxygen partial pressure for Mn-doped BCZT ceramics.Therefore,the Mn-doped ceramics sintered in N_(2)have the highest insulation resistance and best piezoelectric properties(d_(33)=505 pC·N^(-1),k_(p)=50%).The experimental results demonstrate that the Mn-doping element can effectively adjust the intrinsic conduction mechanism and then predict the optimal atmosphere.展开更多
文摘采用传统的固相反应法制备了(Ba_(0.85)Ca_(0.15))(Ti_(0.9)Zr_(0.1))O_(3)(BCZT)以及掺杂Al-Mg-Ca玻璃粉的BCZT无铅压电陶瓷。首先研究了预烧温度对BCZT陶瓷粉体的影响,其次研究了掺杂Al-Mg-Ca玻璃粉对BCZT无铅压电陶瓷的烧结性能、介电性能和压电性能的影响。最后通过正交试验确定了其烧结工艺。结果显示BCZT粉体的最佳预烧温度在1100℃。掺杂Al-Mg-Ca玻璃粉能够有效降低BCZT陶瓷的烧结温度。通过烧结工艺正交实验获得了最佳烧结工艺:1100℃预烧,1350℃烧结,升温速度为2℃/min,保温时间为7 h,在110 min降温至800℃。验证正交试验所得到的结果是掺杂Al-Mg-Ca玻璃粉的BCZT陶瓷的居里温度点的介电常数为12228,压电常数d_(33)为425 p C/N。
基金This work was supported by the Postdoctoral Science Foundation(Nos.BX20490103,2020M681089,LBH-Z19065 and LBHZ13109)the National Natural Science Foundation of China(No.52002093).
文摘Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.
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.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072150 and 51972146)the Young Elite Scientists Sponsorship Program by CAST,the State Key Laboratory of New Ceramics and Fine Processing Tsinghua University(Grant No.KF202002)the Open Foundation of Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices(Grant No.EFMD2021002Z).
文摘The intrinsic conduction mechanism and optimal sintering atmosphere of(Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_(3)(BCZT)ceramics were regulated by Mn-doping element in this work.By Hall and impedance analysis,the undoped BCZT ceramics exhibit a typical n-type conduction mechanism,and the electron concentration decreases with the increasing oxygen partial pressure.Therefore,the undoped ceramics exhibit best electrical properties(piezoelectrical constant<733=585 pC·N^(-1),electro-mechanical coupling factor k_(p)=56%)in O_(2).A handful of Mn-doping element would transfer the conduction mechanism from n-type into p-type.And the hole concentration reduces with the decreasing oxygen partial pressure for Mn-doped BCZT ceramics.Therefore,the Mn-doped ceramics sintered in N_(2)have the highest insulation resistance and best piezoelectric properties(d_(33)=505 pC·N^(-1),k_(p)=50%).The experimental results demonstrate that the Mn-doping element can effectively adjust the intrinsic conduction mechanism and then predict the optimal atmosphere.
