New lead-free piezoceramic nanocomposites of Boron Sodium Gadolinium Niobate(BNGN),with general formula(1-x)B_(0.5)Na_(0.5)GdO3xB_(0.5)Na_(0.5)NbO_(3),exhibiting a Morphotropic Phase Boundary(MPB),have been synthesiz...New lead-free piezoceramic nanocomposites of Boron Sodium Gadolinium Niobate(BNGN),with general formula(1-x)B_(0.5)Na_(0.5)GdO3xB_(0.5)Na_(0.5)NbO_(3),exhibiting a Morphotropic Phase Boundary(MPB),have been synthesized following hydrothermal method followed by solid state sintering.The occurrence of MPB at the composition with x=0.55,at which rhombohedral and monoclinic phases are found to coexist,has been confirmed using powder XRD.This accounts for the occurrence of large remnant polarization when the sintered ceramic pellets are subjected to electric poling at 2KV/mm.Uniform microstructure of various compositions is confirmed by SEM imaging.Dielectric and piezoelectric properties of the samples are found to be comparable to those of commercial grade PZT.At the MPB,the d_(33)coefficient is found to be 556 pC/N,which is close to that of commercial grade PZT,which makes BNGN a promising material to substitute lead containing PZT in the near future.展开更多
(1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3(KNN–x BLZ, x = 0–0.06) lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method, and their phase structures and electric pr...(1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3(KNN–x BLZ, x = 0–0.06) lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method, and their phase structures and electric properties as well as T_C were systematically investigated. The orthorhombic–tetragonal(O–T) two phases were detected in all(1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3 ceramics at 0.01 ≤ x ≤ 0.05. Due to the appropriate ratio between O phase and T phase(CO/C T= 45/55), high piezoelectric properties of d 33= 239 pC/N, k_p= 34%, and P_r = 25.23 μC/cm^2 were obtained at x = 0.04. Moreover, a high T_C = 348 ℃ was also achieved in KNN–x BLZ ceramic at x = 0.04. These results indicate that (1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3 system is a promising candidate for high-temperature piezoelectric devices.展开更多
There are a large number of research publications on the hot topic of environmental friendly leadfree piezoelectric materials worldwide in the last decade.The number of researchers and institutions involved from China...There are a large number of research publications on the hot topic of environmental friendly leadfree piezoelectric materials worldwide in the last decade.The number of researchers and institutions involved from China is much larger than other countries or regions.The publications by Chinese researchers cover a broad spectrum on the preparations,structures,properties and applications of lead-free piezoelectric ceramics.This has motivated us to come out with a review on recent advances in development of lead-free piezoelectric ceramics in China.The emphases are especially on the preparation and electric properties of barium titanate-based materials,bismuth sodium titanate and related materials,alkaline niobate and related materials,bismuth layerstructured materials,as well as texture engineering of ceramics and some of their single crystals.Hopefully,this could give further impetus to the researchers to continue their e®orts in this promising area and also draw the attentions from legislature,research o±ce,industrial and publics.展开更多
（1-x）（K0.47sNa0.475Li0.os）（Nb0.sTa0.2）O3-xBiCoO3 （KNLNT-BC） lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. Effects of the BC content on the phase structure, mi...（1-x）（K0.47sNa0.475Li0.os）（Nb0.sTa0.2）O3-xBiCoO3 （KNLNT-BC） lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. Effects of the BC content on the phase structure, microstructure and electrical properties of KNLNT-BC ceramics were investigated. XRD patterns reveal that all the ceramic samples are in the pure perovskite-type structure, and the phase structure changes from the tetragonal to pseudo-cubic phase with the increase of the BC content. After the substitution of BC, the grain size is significantly reduced and relaxer behaviors are induced. By adding a small amount of BC to KNLNT ceramics, piezoelectric properties are improved, while further addition of BC makes the piezoelectric properties deteriorate markedly. The optimized electrical properties atx= 0.005 are as follows： d33 = 194 pC/N, kp = 0.44.展开更多
Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant progress.However,attaining a high electrostrain with remarkable temperature stability and minimal hy...Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant progress.However,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant challenge.To address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation engineering.The LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)ceramics.Importantly,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local heterogeneity.This work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.展开更多
In this paper,Sm-doped 0.96(K0.48 Na0.52)(Nb0.95 Sb0.05)–0.04 Bi0.5(Na0.82 K0.18)0.5 Zr O3(abbreviated as KNSN–0.04 BNKZ)lead-free piezoelectric ceramics were prepared by conventional solid-state sintering method an...In this paper,Sm-doped 0.96(K0.48 Na0.52)(Nb0.95 Sb0.05)–0.04 Bi0.5(Na0.82 K0.18)0.5 Zr O3(abbreviated as KNSN–0.04 BNKZ)lead-free piezoelectric ceramics were prepared by conventional solid-state sintering method and the effects of Sm2 O3 on the phase structure,microstructure,electrical and luminescent properties of KNSN–0.04 BNKZ potteries were studied.Results revealed that a single solid solution phase with pseudo-cubic perovskite structure was formed between KNSN–0.04 BNKZ and Sm2 O3.Existence of weak dielectric/ferroelectric properties with a diffuse dielectric anomaly and slim P–E hysteresis loops of the Sm-doped KNSN–0.04 BNKZ demonstrated the ferroelectric relaxor behavior of the KNNS–0.04 BNKZ–x Sm ceramics.Accordingly,the temperature stability and fatigue behavior of the modified ceramics were significantly improved.It was found that the KNSN–0.04 BNKZ ceramics with 0.002 mol Sm addition exhibited nearly temperature independent properties and fatigue-free behavior.Moreover,Sm-modified KNSN–0.04 BNKZ exhibits a bright photoluminescence with a strong orange emission under visible light irradiation.As a material with both electrical and luminescent properties,it has good application prospect in future optoelectronic components by integrating its luminescent and electrical properties.展开更多
Lead-free （K0.5Na0.5）（Nb1-xGex）O3 （KNN-xGe, where x = 0-0.01） piezo- electric ceramics were prepared by conventional ceramic processing. The effects of Ge4＋cation doping on the phase compositions, microstructur...Lead-free （K0.5Na0.5）（Nb1-xGex）O3 （KNN-xGe, where x = 0-0.01） piezo- electric ceramics were prepared by conventional ceramic processing. The effects of Ge4＋cation doping on the phase compositions, microstructure and electrical properties of KNN ceramics were studied. SEM images show that Ge4＋ cation doping improved the sintering and promoted the grain growth of the KNN ceramics. Dielectric and ferroelectric measurements proved that Ge4＋ cations substituted Nbs＋ ions as acceptors, and the Curie temperature （Tc） shows an almost linear decrease with increasing the Ge4＋ content. Combining this result with microstructure observations and electrical measurements, it is concluded that the optimal sintering temperature for KNN-xGe ceramics was 1020℃. Ge4＋ doping less than 0.4 mol.% can improve the compositional homogeneity and piezoelectric properties of KNN ceramics. The KNN-xGe ceramics with x = 0.2% exhibited the best piezoelectric properties： piezoelectric constant d33 = 120 pC/N, planar electromechanical coupling coefficient kp = 34.7%, mechanical quality factor Qm = 130, and tanδ = 3.6%.展开更多
文摘New lead-free piezoceramic nanocomposites of Boron Sodium Gadolinium Niobate(BNGN),with general formula(1-x)B_(0.5)Na_(0.5)GdO3xB_(0.5)Na_(0.5)NbO_(3),exhibiting a Morphotropic Phase Boundary(MPB),have been synthesized following hydrothermal method followed by solid state sintering.The occurrence of MPB at the composition with x=0.55,at which rhombohedral and monoclinic phases are found to coexist,has been confirmed using powder XRD.This accounts for the occurrence of large remnant polarization when the sintered ceramic pellets are subjected to electric poling at 2KV/mm.Uniform microstructure of various compositions is confirmed by SEM imaging.Dielectric and piezoelectric properties of the samples are found to be comparable to those of commercial grade PZT.At the MPB,the d_(33)coefficient is found to be 556 pC/N,which is close to that of commercial grade PZT,which makes BNGN a promising material to substitute lead containing PZT in the near future.
基金supported by Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20130006110006)National Natural Science Foundation of China(Grant Nos.51272023 and 51472026)
文摘(1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3(KNN–x BLZ, x = 0–0.06) lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method, and their phase structures and electric properties as well as T_C were systematically investigated. The orthorhombic–tetragonal(O–T) two phases were detected in all(1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3 ceramics at 0.01 ≤ x ≤ 0.05. Due to the appropriate ratio between O phase and T phase(CO/C T= 45/55), high piezoelectric properties of d 33= 239 pC/N, k_p= 34%, and P_r = 25.23 μC/cm^2 were obtained at x = 0.04. Moreover, a high T_C = 348 ℃ was also achieved in KNN–x BLZ ceramic at x = 0.04. These results indicate that (1–x)K_(0.48)Na_(0.56)NbO_3–xBi_(0.5)Li_(0.5)ZrO_3 system is a promising candidate for high-temperature piezoelectric devices.
基金supports from The National Nature Science Foundation of China(NSFC,Nos.50072039,20151003,50572113,50932007)The Ministry of Sciences and Technology of China(MOST)through 973-projects(Nos.2002CB613307,2009CB623305)+3 种基金863-Projects(Nos.2001AA325070,2006AA03Z430)The Science and Technology Commission of Shanghai Municipality(Nos.05JC14079,08JC1420500,10XD1404700)Shanghai Institute of Ceramics(No.SCX200409)are gratefully acknowledged.
文摘There are a large number of research publications on the hot topic of environmental friendly leadfree piezoelectric materials worldwide in the last decade.The number of researchers and institutions involved from China is much larger than other countries or regions.The publications by Chinese researchers cover a broad spectrum on the preparations,structures,properties and applications of lead-free piezoelectric ceramics.This has motivated us to come out with a review on recent advances in development of lead-free piezoelectric ceramics in China.The emphases are especially on the preparation and electric properties of barium titanate-based materials,bismuth sodium titanate and related materials,alkaline niobate and related materials,bismuth layerstructured materials,as well as texture engineering of ceramics and some of their single crystals.Hopefully,this could give further impetus to the researchers to continue their e®orts in this promising area and also draw the attentions from legislature,research o±ce,industrial and publics.
文摘（1-x）（K0.47sNa0.475Li0.os）（Nb0.sTa0.2）O3-xBiCoO3 （KNLNT-BC） lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. Effects of the BC content on the phase structure, microstructure and electrical properties of KNLNT-BC ceramics were investigated. XRD patterns reveal that all the ceramic samples are in the pure perovskite-type structure, and the phase structure changes from the tetragonal to pseudo-cubic phase with the increase of the BC content. After the substitution of BC, the grain size is significantly reduced and relaxer behaviors are induced. By adding a small amount of BC to KNLNT ceramics, piezoelectric properties are improved, while further addition of BC makes the piezoelectric properties deteriorate markedly. The optimized electrical properties atx= 0.005 are as follows： d33 = 194 pC/N, kp = 0.44.
基金This study was financially supported by the National Natural Science Foundation of China(Nos.52032007 and 52072028)the National Key R&D Program(No.2022YFB3807400)+1 种基金the Basic Science Center Project of National Natural Science Foundation of China(No.52388201)Tsinghua University-Toyota Research Center.
文摘Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant progress.However,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant challenge.To address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation engineering.The LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)ceramics.Importantly,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local heterogeneity.This work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.
基金the National Key R&D Program of China(No.2016YFB0402701)Innovation Team of Higher Educational Science and Technology Program in Shandong Province(No.2019KJA025)+3 种基金National Natural Science Foundation of China(Nos.51701091 and 51802137)Natural Science Foundation of Shandong Province of China(Nos.ZR2018MEM011 and ZR201709270099)Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(Grant No.KLIFMD201705)Research Foundation of Liaocheng University(No.318011906)。
文摘In this paper,Sm-doped 0.96(K0.48 Na0.52)(Nb0.95 Sb0.05)–0.04 Bi0.5(Na0.82 K0.18)0.5 Zr O3(abbreviated as KNSN–0.04 BNKZ)lead-free piezoelectric ceramics were prepared by conventional solid-state sintering method and the effects of Sm2 O3 on the phase structure,microstructure,electrical and luminescent properties of KNSN–0.04 BNKZ potteries were studied.Results revealed that a single solid solution phase with pseudo-cubic perovskite structure was formed between KNSN–0.04 BNKZ and Sm2 O3.Existence of weak dielectric/ferroelectric properties with a diffuse dielectric anomaly and slim P–E hysteresis loops of the Sm-doped KNSN–0.04 BNKZ demonstrated the ferroelectric relaxor behavior of the KNNS–0.04 BNKZ–x Sm ceramics.Accordingly,the temperature stability and fatigue behavior of the modified ceramics were significantly improved.It was found that the KNSN–0.04 BNKZ ceramics with 0.002 mol Sm addition exhibited nearly temperature independent properties and fatigue-free behavior.Moreover,Sm-modified KNSN–0.04 BNKZ exhibits a bright photoluminescence with a strong orange emission under visible light irradiation.As a material with both electrical and luminescent properties,it has good application prospect in future optoelectronic components by integrating its luminescent and electrical properties.
基金The authors thank Jianqiang Zhou for his technical help with SEM measurements. This work was supported by the National Natural Science Foundation of China （Grant No. 21371056） and the Fundamental Research Funds for the Central Universities （Grant No. 2015ZZD04）.
文摘Lead-free （K0.5Na0.5）（Nb1-xGex）O3 （KNN-xGe, where x = 0-0.01） piezo- electric ceramics were prepared by conventional ceramic processing. The effects of Ge4＋cation doping on the phase compositions, microstructure and electrical properties of KNN ceramics were studied. SEM images show that Ge4＋ cation doping improved the sintering and promoted the grain growth of the KNN ceramics. Dielectric and ferroelectric measurements proved that Ge4＋ cations substituted Nbs＋ ions as acceptors, and the Curie temperature （Tc） shows an almost linear decrease with increasing the Ge4＋ content. Combining this result with microstructure observations and electrical measurements, it is concluded that the optimal sintering temperature for KNN-xGe ceramics was 1020℃. Ge4＋ doping less than 0.4 mol.% can improve the compositional homogeneity and piezoelectric properties of KNN ceramics. The KNN-xGe ceramics with x = 0.2% exhibited the best piezoelectric properties： piezoelectric constant d33 = 120 pC/N, planar electromechanical coupling coefficient kp = 34.7%, mechanical quality factor Qm = 130, and tanδ = 3.6%.
