Lead-free ceramics （Ba0.85Ca0.15）（Zr0.1Ti0.9）O3-x wt,%Cr2O3 （BCZT-xCr） were prepared via the conventional solid-state reaction method. The microstructure and electrical properties of BCZT-xCr samples were system...Lead-free ceramics （Ba0.85Ca0.15）（Zr0.1Ti0.9）O3-x wt,%Cr2O3 （BCZT-xCr） were prepared via the conventional solid-state reaction method. The microstructure and electrical properties of BCZT-xCr samples were systematically studied. XRD and Raman results showed that all samples possessed a single phased perovskite structure and were close to the morphotropic phase boundary （MPB）. With the increase of the Cr content, the rhombohedral-tetragonal phase transition temperature （TR-T） increases slightly, and the Curie temperature （Tc） shifts towards the low temperature side. XPS analysis reveals that Cr3. and Cr5＊ ions co-existed in Cr-doped BCZT ceramics, indicating the different impact on the electrical properties from Cr ions as ＂acceptor＂ or ＂donor＂. For the x = 0.1 sample, relative high piezoelectric constants d33 （-316 pC/N） as well as high Qm （-554） and low tan6 （-0.8%） were obtained. In addition, the AC conductivity was also investigated. Hopping charge was considered as the main conduction mechanism at low temperature. As the temperature increases, small polarons and oxygen vacancies conduction played important roles.展开更多
In this work,a traditional solid-state method was adopted to prepare dense Ba_(0.85)Ca_(0.15)[(Zr_(0.1)Ti_(0.9))_(1-x)–(Nb_(0.5)La_(0.5))_(x)]O_(3)(BCZT–xNL)lead-free relaxation ferroelectrics with excellent energy ...In this work,a traditional solid-state method was adopted to prepare dense Ba_(0.85)Ca_(0.15)[(Zr_(0.1)Ti_(0.9))_(1-x)–(Nb_(0.5)La_(0.5))_(x)]O_(3)(BCZT–xNL)lead-free relaxation ferroelectrics with excellent energy storage performance(ESP).Remarkably,a large breakdown field strength of BDS(-410 kV/cm)resulting from decreased grain size by double ions doping at the B-site was achieved in BCZT–xNL ceramics.Especially,the BCZT–0.12NL ceramic displays a good recoverable energy density(W_(rec))of 3.1 J/cm^(3),a high efficiency of 86.7%(η)and a superior fatigue resistance,as well as a superior charge–discharge performance(C_(D)-1623.14 A/cm^(2),P_(D)-162.31 MW/cm^(3),W_(D)-1.30 J/cm^(3),t_(0.9)-49.6 ns)and good thermal stability.Besides,upon NL doping,the FE to RFE phase transition results in a dielectric behavior traversing the relaxation phase(γ-1.84)accompanied by frequency dispersion,which is beneficial to improve ESP.The superior ESP in this work indicates that BCZT–0.12NL ceramics are a promising candidate used in energy storage capacitors.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
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
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
Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Her...Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Here we demonstrate an approach for the reduction of the sintering temperature and simultaneous increase of the electromechanical strain response of(Ba,Ca)(Zr,Ti)O3 piezoceramics by aliovalent doping with Ce. The samples were prepared by solid state synthesis and their crystallographic structure, dielectric, ferroelectric, and electromechanical properties were investigated. The highest d33* value of 1189 pm/V was obtained for the sample with 0.05 mol% Ce, substituted on the A-site of the perovskite lattice. The results indicate a large potential of these materials for off-resonance piezoelectric actuators.展开更多
文摘Lead-free ceramics （Ba0.85Ca0.15）（Zr0.1Ti0.9）O3-x wt,%Cr2O3 （BCZT-xCr） were prepared via the conventional solid-state reaction method. The microstructure and electrical properties of BCZT-xCr samples were systematically studied. XRD and Raman results showed that all samples possessed a single phased perovskite structure and were close to the morphotropic phase boundary （MPB）. With the increase of the Cr content, the rhombohedral-tetragonal phase transition temperature （TR-T） increases slightly, and the Curie temperature （Tc） shifts towards the low temperature side. XPS analysis reveals that Cr3. and Cr5＊ ions co-existed in Cr-doped BCZT ceramics, indicating the different impact on the electrical properties from Cr ions as ＂acceptor＂ or ＂donor＂. For the x = 0.1 sample, relative high piezoelectric constants d33 （-316 pC/N） as well as high Qm （-554） and low tan6 （-0.8%） were obtained. In addition, the AC conductivity was also investigated. Hopping charge was considered as the main conduction mechanism at low temperature. As the temperature increases, small polarons and oxygen vacancies conduction played important roles.
基金supported by the National Science Foundation of China(NSFC)(Grant Nos.52272119 and 52202143)The authors would also like to thank the Natural Science Basic Research Plan in the Shaanxi Province of China(Grant No.2022JQ338)+3 种基金Young Talent Fund of University Association for Science and Technology in Shaanxi,China(20230415)the Fundamental Research Funds for the Central Universities(Grant No.GK202401009)Key Research and Development Program of Shaanxi Provincial Science and Technology Department(Grant No.2023-YBGY-162)the Fundamental Innovation Project in School of Materials Science and Engineering(SNNU).
文摘In this work,a traditional solid-state method was adopted to prepare dense Ba_(0.85)Ca_(0.15)[(Zr_(0.1)Ti_(0.9))_(1-x)–(Nb_(0.5)La_(0.5))_(x)]O_(3)(BCZT–xNL)lead-free relaxation ferroelectrics with excellent energy storage performance(ESP).Remarkably,a large breakdown field strength of BDS(-410 kV/cm)resulting from decreased grain size by double ions doping at the B-site was achieved in BCZT–xNL ceramics.Especially,the BCZT–0.12NL ceramic displays a good recoverable energy density(W_(rec))of 3.1 J/cm^(3),a high efficiency of 86.7%(η)and a superior fatigue resistance,as well as a superior charge–discharge performance(C_(D)-1623.14 A/cm^(2),P_(D)-162.31 MW/cm^(3),W_(D)-1.30 J/cm^(3),t_(0.9)-49.6 ns)and good thermal stability.Besides,upon NL doping,the FE to RFE phase transition results in a dielectric behavior traversing the relaxation phase(γ-1.84)accompanied by frequency dispersion,which is beneficial to improve ESP.The superior ESP in this work indicates that BCZT–0.12NL ceramics are a promising candidate used in energy storage capacitors.
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.
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.
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funded by Ministry of Science,Research and Technology of Iran as a Ph.D.project,with Grant No.481392053,at Materials&Energy Research Center(MERC)supported by Deutsche Forschungsgemeinschaft under the Sonderforschungsbereich 595(SFB 595)fellowship
文摘Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Here we demonstrate an approach for the reduction of the sintering temperature and simultaneous increase of the electromechanical strain response of(Ba,Ca)(Zr,Ti)O3 piezoceramics by aliovalent doping with Ce. The samples were prepared by solid state synthesis and their crystallographic structure, dielectric, ferroelectric, and electromechanical properties were investigated. The highest d33* value of 1189 pm/V was obtained for the sample with 0.05 mol% Ce, substituted on the A-site of the perovskite lattice. The results indicate a large potential of these materials for off-resonance piezoelectric actuators.
