Ce~(3+)掺杂Na_(0.5)Bi_(8.5)Ti_7O_(27)铋层状陶瓷的结构与电性能研究

采用固相法制备了Ce~(3+)掺杂的Na_(0.5)Bi_(8.5–x)Ce_xTi_7O_(27)(NBT-BIT-x Ce,0≤x≤0.1)共生铋层状无铅压电陶瓷,研究了NBT-BIT-xCe陶瓷的结构和电学性能。研究结果表明所有陶瓷样品均为单一的铋层状结构,随Ce~(3+)掺杂量的增加,样品的畸变程度呈现上升趋势,同时陶瓷晶粒的平均尺寸不断减小,介温谱和差热分析结果表明样品的介电双峰均对应于陶瓷内部结构的铁电相变。Ce~(3+)掺杂可以显著减少陶瓷内部的氧空位浓度以及降低陶瓷的介电损耗,提升陶瓷的压电常数(d33),当x=0.06时,陶瓷的综合电性能最佳:压电常数(d_(33))达到27.5 pC/N,居里温度(TC)达到658.2℃,介电损耗(tanδ)为0.39%。     

Mn改性Na0.5Bi2.5Nb2O9高温压电陶瓷的研究

采用固相法获得了Mn改性的Na0.5Bi2.5Nb2O9(NBN+xmol%MnCO3,0≤x≤10.0)铋层状压电陶瓷,并系统地研究了Mn(掺杂)对NBN基陶瓷显微结构与电性能的影响.结果表明,所有获得的样品都是居里点在700℃以上的单一相铁电体.加入Mn显著地提高了NBN系列陶瓷的机械品质因素Qm,明显改善了陶瓷的压电与机电性能.当MnCO3掺杂量为8.0mol%时,陶瓷获得最佳电性能:tanδ=0.749%,d33=20 pC/N,Qm=3120,kp=12.37%,kt=21.09%,Pr=7.01μC/cm2.NBN+xmol%MnCO3(x=8.0)陶瓷经700℃退极化处理后,其d33保持为原来的75%(~15 pC/N),表明该材料在高温领域下具有良好的应用前景.     

(1-x)(Na0.5K0.5)NbO3-x(Ba0.88Ca0.12Zr0.12Ti0.88O3) 无铅压电陶瓷的制备及性能研究

介绍了一种利用传统固态烧结法制作的无铅压电陶瓷(1-x)(Na_(0.5)K_(0.5))NbO_3-x(Ba_(0.88)Ca_(0.12)Zr_(0.12)Ti_(0.88)O_3)((1-x)KNN-xBCZT)。(1-x)KNN-xBCZT是由KNN和BCZT形成的均匀固溶体。随着BCZT浓度的增加,(1-x)KNN-xBCZT的T_c和四方相-正交相的相变温度呈近似直线方式下降。相变温度的降低,有助于提升固溶体的电性能,当x=0.055时(1-x)KNN-xBCZT陶瓷性能达到最优。MnO_2助烧剂可以进一步降低(1-x)KNN-xBCZT陶瓷的相变温度,使(1-x)KNN-xBCZT陶瓷更为致密。0.055BCZT-0.945KNN-0.01MnO_2陶瓷展现出的性能为d_(33)=212 pC/N,d_(31)=-75 pC/N,k_p=45%,ε=875,tanδ=0.02和T_C=340℃,T_(O-T)=127℃。     

(0.84-x)Na_(0.5)Bi_(0.5)TiO_3-0.16K_(0.5)Bi_(0.5)TiO_(3-x)SrTiO_3系无铅压电陶瓷结构与电性能

采用固相法制备了Bi补偿的(0.84-x)Na0.5Bi0.5TiO3-0.16K0.5Bi0.5TiO3-x SrTiO3(简称NBTKBT-xST)无铅压电陶瓷,研究不同ST掺量对体系陶瓷的结构与电性能的影响规律。结果表明,在掺杂范围内(0≤x≤0.06),材料均能形成单一的钙钛矿固溶体结构。随着x的增加,陶瓷晶体结构逐渐由三方相向四方相过渡,且该体系的三方-四方准同型相界(MPB)位于0.03≤x≤0.04。在此组成区域内,体系陶瓷的铁电与压电性能较好,其中x=0.04时,材料的电性能较好:压电常数d33=156 pC/N,平面机电耦合系数k p=0.29,相对介电常数εr=1116,介质损耗tanδ=4.1%,剩余极化强度P r=30.5μC/cm2,矫顽场E c=23.9 kV/cm。介电温谱和变温电滞回线表明体系陶瓷在T d以上可能存在极性相与非极性相共存。     

高压电常数PSN-PZT压电陶瓷的制备与性能研究

采用传统的固相烧结法制备了三元系Pb_(0.82)Sr_(0.13)Ba_(0.05)(Sb_(1/3)Nb_(2/3))_(0.02)(Zr_(1/2)Ti_(1/2))_(0.98)O_3-wBi_2O_3(PSN-PZT-wBi)压电陶瓷,并研究了Bi~(3+)掺杂对压电陶瓷电性能的影响。结果表明,当Bi_2O_3掺杂量在0.25wt%时,PSN-PZT压电陶瓷具有最优异的电学性能:d_(33)=980 pC/N,k_p=0.83,ε_r=6 855,tanδ=0.04,T_c=150℃。     

CeO_2掺杂对Pb_(0.92)Sr_(0.06)Ba_(0.02)(Sb_(2/3)Mn_(1/3))_(0.05)Zr_(0.48)Ti_(0.47)O_3基压电陶瓷相结构及性能的影响

采用传统固相烧结法制备Pb_(0.92)Sr_(0.06)Ba_(0.02)(Sb_(2/3)Mn_(1/3))_(0.05)Zr_(0.48)Ti_(0.47)O_3∶xCeO_2(简称PSBSM-PZT)压电陶瓷样品。研究不同CeO_2掺杂含量对PSBSM-PZT基陶瓷样品的物相结构、微观形貌、压电及介电性能的影响。结果表明:当CeO_2掺杂量x≤0.5%(质量分数,下同)时,陶瓷样品均为纯的钙钛矿结构。随着CeO_2掺杂含量的增加,陶瓷样品中四方相结构逐渐向三方相结构转变。随着CeO_2掺杂含量的进一步增加,陶瓷中出现焦绿石相,虽然陶瓷中已经出现焦绿石相,但是样品仍没有完全转变为三方相陶瓷;CeO_2掺杂具有细化晶粒的作用,当x=0.25%时样品晶粒晶界清晰,晶粒之间的结合相对致密,晶界处气孔率低,陶瓷断裂方式以沿晶断裂为主;当x=0.25%时,陶瓷样品获得最佳的压电与介电性能:d_(33)=346pC/N,k_p=0.60,Q_m=1396,ε_r=1309,tanδ=0.474%。     

CeO_2掺杂制备Ba_(0.9)Ca_(0.1)Ti_(1-x)Sn_xO_3压电陶瓷的结构及电性能（英文）

采用传统的陶瓷烧结技术,通过添加0.15%(摩尔分数)CeO_2,在1 120℃烧结2h,成功制备了新型无铅压电陶瓷Ba_(0.9)Ca_(0.1)Ti_(1-x)Sn_xO_3,并且检测了陶瓷样品的微结构和电性能。XRD显示所有陶瓷样品均具有纯的钙钛矿结构,在室温下为典型的四方相,SEM显示适量添加锡离子可以提高陶瓷致密性。在室温下,锡离子改性的BaTiO_3基压电陶瓷在x=0.02处显示了优异的压电、介电和铁电性能(d_(33)=276pC/N,k_p=46%,ε_r=3 678,tanδ=2.4%,P_r=18.2μC/cm~2,E_C=1.12kV/mm)。这些优异的检测结果证实适当添加锡离子能改善BaTiO_3基压电陶瓷的电性能。     

(1-x)BaTiO_(3-x)Ag_(0.9)Li_(0.1)NbO_3系无铅压电陶瓷的相结构和电性能研究

采用传统陶瓷工艺制备了(1-x)BaTiO_(3-x)Ag_(0.9)Li_(0.1)NbO_3(BT-xALN,0.005≤x≤0.04)系陶瓷,研究了ALN含量的变化对BT-xALN系陶瓷的显微结构、相结构和电性能的影响。结果表明,ALN的引入使陶瓷的晶粒尺寸有所减小。当x≤0.02时,BT-xALN陶瓷均形成了纯的钙钛矿相,表明ALN与BT形成了固溶体;当x=0.01~0.02时,陶瓷存在四方-伪立方相界。陶瓷的压电常数d33和介电常数εr随x增加均先增大后减小。d33在x=0.0075时达到最大值115pC/N,εr在x=0.025时达到最大值3 880;但剩余极化强度Pr随x增加逐渐降低。此外,掺入ALN后陶瓷的居里温度有所降低。     

(0.98-x)BNT-xBKT-0.02BZN无铅压电陶瓷的制备及性能研究

采用传统固相烧结法制备(0.98-x)Bi1/2Na1/2TiO3-xBi1/2K1/2TiO3-0.02Bi(Zn2/3Nb1/3)O3(简称(0.98-x)BNT-xBKT-0.02BZN,其中x=0.1、0.15、0.20、0.25)无铅压电陶瓷,系统研究了不同烧结温度对(0.98-x)BNT-xBKT-0.02BZN陶瓷压电及介电性能的影响。结果表明,压电常数和机电耦合系数都随烧结温度的升高而增大,得出1140℃为最佳烧结温度,其最佳性能如下:d33=43pC/N,Kp=0.2731,ε3T3/ε0=1289.8,tanδ=0.038。     

CeO_2掺杂对SrNa_(0.5)Bi_(4.5)Ti_5O_(18)高温无铅压电陶瓷性能的影响

用固相合成法制备SrNa0.5Bi4.5Ti5O18+x%(质量分数)CeO2(SNBTCx)铋层状无铅压电陶瓷,研究了CeO2掺杂对SNBTCx陶瓷微观结构和电性能的影响。结果表明,CeO2掺杂并未改变SNBTCx陶瓷的晶体结构,所有样品均为单一的铋层状结构陶瓷;CeO2掺杂没有使SNBTCx陶瓷居里温度发生明显变化,居里温度均高于560℃;随着CeO2掺杂量的增加SNBTCx陶瓷材料的介电常数减小,但是其介电损耗先增大后减小。当CeO2掺杂量为0.3%(质量分数)时SNBTC0.03陶瓷具有最优电性能:Tc=567℃,d33=29 p C/N,tanδ=0.015,且在500℃退极化处理后,其d33仍保持在22 p C/N以上,说明SNBTC0.03陶瓷可在高温下应用。     

Sm2O3掺杂(Ba0.7Ca0.3)TiO3-Ba(Zr0.2Ti0.8)O3无铅压电陶瓷的制备与性能

采用固相合成法制备了Sm2O3掺杂的(Ba0.7Ca0.3)TiO3-Ba(Zr0.2Ti0.8)O3(BCZT)无铅压电陶瓷.借助XRD、SEM等手段对该陶瓷的显微结构与电性能进行了研究.结果表明,Sm2O3的掺杂降低了BCZT无铅压电陶瓷的烧结温度并使居里温度点Tc从85℃提高到95℃.当Sm2O3掺杂量为0.02wt%～0.1wt%时,样品具有典型ABO3型钙钛矿结构.Sm2O3掺杂量为0.02wt%时,所得陶瓷样品具有最优综合电性能,其压电常数d33、机电耦合系数kp、机械品质因子Qm、介电损耗tanδ和介电常数εr分别为590 pC/N、0.52、43、1.3%和3372.     

CeO2掺杂制备Ba0.9Ca0.1Ti1-xSnxO3压电陶瓷的结构及电性能

采用传统的陶瓷烧结技术,通过添加0.15%(摩尔分数)CeO2,在1120℃烧结2h,成功制备了新型无铅压电陶瓷Ba0.9 Ca0.1 Ti1-x Snx O3,并且检测了陶瓷样品的微结构和电性能.XRD显示所有陶瓷样品均具有纯的钙钛矿结构,在室温下为典型的四方相,SEM显示适量添加锡离子可以提高陶瓷致密性.在室温下,锡离子改性的BaTiO3基压电陶瓷在x=0.02处显示了优异的压电、介电和铁电性能(d33=276 pC/N,kp=46%,εr=3678,tanδ=2.4%,Pr=18.2μC/cm2,EC=1.12 kV/mm).这些优异的检测结果证实适当添加锡离子能改善BaT iO3基压电陶瓷的电性能.     

BaZrO3掺杂对(K0.49Na0.51)0.98Li0.02(Nb0.77Ta0.18Sb0.05)O3无铅压电陶瓷的结构与电性能的影响

采用固相反应法制备了(K_0.49Na_0.51)_0.98Li_0.02(Nb_0.77Ta_0.18Sb_0.05)O₃-xBaZrO₃ (NKNLST-xBZ, x = 0~0.020 mol)无铅压电陶瓷, 系统研究了BaZrO₃的掺杂量对陶瓷的压电、介电、机电和铁电性能的影响。结果表明: 随着BaZrO₃掺杂量x的增加, 陶瓷的晶体结构由正交相向四方相转变, 在x=0.005~0.008区间出现正交相与四方相两相共存的区域, 在此区域内陶瓷的晶粒变得细小且均匀, 介电损耗tanδ大幅降低, 压电常数d₃₃和平面机电耦合系数k_p增加。该体系陶瓷的介电常数ε T 33 /ε0则随着BaZrO₃的增加持续增加, 相变温度则向低温方向移动。当x=0.005时, 该组成陶瓷具有最佳的综合性能: 压电常数d33=372 pC/N, 平面机电耦合系数kp=47.2%, 介电损耗tanδ=3.1%, 以及较高的介电常数ε^T₃₃ /ε₀=1470和居里温度T_c=208℃。     

Phase-transition temperatures and piezoelectric properties of (Bi1/2Na1/2)TiO3-(Bi1/2Li1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics.

The phase-transition temperatures and piezoelectric properties of x(Bi(1/2)Na(1/2))TiO3-y(Bi(1/2)Li(1/2))TiO3-z(Bi(1/2)K(1/2))TiO3 [x + y + z = 1] (abbreviated as BNLKT100(y)-100(z)) ceramics were investigated. These ceramics were prepared using a conventional ceramic fabrication process. The phase-transition temperatures such as depolarization temperatures T(d), rhombohedraltetragonal phase transition temperature T(R-T), and dielectric-maximum temperature T(m) were determined using electrical measurements such as dielectric and piezoelectric properties. The X-ray powder diffraction patterns of BNLKT100(y)-100(z)) show the morphotropic phase boundary (MPB) between rhombohedral and tetragonal at approximately z = 0.20, and the piezoelectric properties show the maximum at the MPB. The electromechanical coupling factor k(33), piezoelectric constant d(33) and T(d) of BNLKT4-20 and BNLKT8-20 were 0.603, 176 pC/N, and 171 degrees C, and 0.590, 190 pC/N, and 115 degrees C, respectively. In addition, the relationship between d33 and Td of tetragonal side and rhombohedral side for BNLKT4-100z and BNLKT8-100z were presented. Considering both high Td and high d(33), the tetragonal side of BNLKT4-100z is thought to be the superior composition. The d(33) and T(d) of BNLKT4-28 were 135 pC/N and 218 degrees C, respectively. Moreover, this study revealed that the variation of T(d) is related to the variation of lattice distortion such as rhombohedrality 90-alpha and tetragonality c/a.     

Dielectric, piezoelectric, and ferroelectric properties of MnCO3-added 74(Bi1/2Na}1/2) TiO3-20.8(Bi1/2K1/2)TiO3-5.2BaTiO3 lead-free piezoelectric ceramics

74(Bi1/2Na1/2)TiO{i3}-20.8(Bi1/2K1/2)TiO3-5.2BaTiO3-x MnCO3 lead-free piezoelectric ceramics were synthesized by conventional solid oxide routine. The tetragonal 74(Bi1/2Na1/2)TiO3-20.8(Bi1/2K1/2)TiO3-5.2 BaTiO3 (BNKB) exhibits high depolarization temperature Td of 195°C; however, its properties are far from satisfactory for practical application and need to be improved. The experiments show that the addition of MnCO3 reduces the tetragonality c/a and increases the cell volume. In addition, it revealed that the suitable addition of MnCO3 promotes the sintering and increases the densities of BNKB ceramics. The addition of MnCO3 also enhances the relaxor behavior of BNKB ceramics due to the reconstruct of the disorder arrays. Due to the effect of the crystal lattice, grain growth, and relaxor behavior, the optimal electric properties were realized at MnCO3 addition x of 0.16: the dielectric permittivity εr = 1047, dielectric dissipation tanδ = 0.022, piezoelectric strain d33 = 140 pC/N, mechanical coupling kp = 0.18, mechanical quality Qm = 89 while the depolarization temperature Td stays relatively high at 175°C. The effect and mechanism of Mn doping on the electrical properties were discussed in detail.     

Piezoelectric ceramics with high dielectric constants for ultrasonic medical transducers

Complex system ceramics Pb(Sc(1/2)Nb(1/2))O3-Pb(Mg(1/3)Nb(2/3))O3-Pb(Ni(1/2)Nb(1/2))O3-(Pb0.965,Sr0.035) (Zr,Ti)O3 (PSN-PMN-PNN-PSZT abbreviated PSMNZT) have been synthesized by the conventional technique, and dielectric and piezoelectric properties of the ceramics have been investigated for ultrasonic medical transducers. High capacitances of the transducers are desired in order to match the electrical impedance between the transducers and the coaxial cable in array probes. Although piezoelectric ceramics that have high dielectric constants (epsilon33t/epsilon0 > 5000, k'33 < 70%) are produced in many foundries, the dielectric constants are insufficient. However, we have reported that low molecular mass B-site ions in the lead-perovskite structures are important in realizing better dielectric and piezoelectric properties. We focused on the complex system ceramics PSMNZT that consists of light B-site elements. The maximum dielectric constant, epsilon33T/epsilon0 = 7, 200, was confirmed in the ceramics, where k'33 = 69%, d33 = 940 pC/N, and T(c) = 135 degrees C were obtained. Moreover, pulse-echo characteristics were simulated using the Mason model. The PSMNZT ceramic probe showed echo amplitude about 5.5 dB higher than that of the conventional PZT ceramic probe (PZT-5H type). In this paper, the electrical properties of the PSMNZT ceramics and the simulation results for pulse-echo characteristics of the phased-array probes are introduced.     

退火处理对铅基弛豫型铁电体介电、压电性能的影响

铅基弛豫型铁电体的峰值介电常数和压电性能在退火后有较大提高．在PMN－PT陶瓷中,k_p由58％提高到66％,峰值介电常数由30900提高到37200,d_(33)达到530pC／N.在PZN－PT－BT陶瓷中,k_p由35％提高到51％,峰值介电常数km由11400提高到29000,d_(33)由347PC／N提高到624pC／N．这种改善可能与晶界玻璃相的消除以及畴壁运动等因素有关     

含铋层状结构陶瓷CaBi2Nb2O9的A位掺杂改性研究

利用固相反应法合成了Ca1-x(KLa)x/2Bi2Nb2O9(x=0～0.20)(xKLaCBNO)铋层状陶瓷,分析不同KLa掺杂量对CaBi2Nb2O9(CBNO)基陶瓷微观结构、介电、压电及电导性能的影响.XRD分析表明KLa的引入未改变CBNO陶瓷的单相结构.SEM和介电系数温度谱结果分别显示,KLa掺杂量的增加,细化尺寸趋于一致,而居里温度(Tc)从943℃降低至875℃,其峰值介电常数减小、峰值介电损耗增大.当掺杂量x=0.1时,样品的高温电阻率较纯CBNO显著升高,压电系数d33由5.2 pC/N提高到15.8 pC/N,居里温度高达870℃,说明A位(KLa)掺杂改性后的CBNO陶瓷在高温传感器等领域具有潜在的应用前景.