陶瓷粉体粒度对PZN—PZT／PVDF压电复合材料性能的影响

将铌锌锆钛酸铅（PZN—PZT）压电陶瓷粉体分散于聚偏二氟乙烯（PVDF）基体中,制备出0-3型PZN—PZT／PVDF压电复合材料。文中研究了PZN—PZT陶瓷不同粒度对复合材料的压电性、介电性、铁电性的影响。结果表明,当陶瓷粒度为100～150目时,压电复合材料的综合性能最佳,压电常数d33达到23．10pC／N,剩余极化强度Pr达到5．131μC·era2,矫顽场Ec为45．7lkV·cm^-1,介电常数ε。为192．86,介电损耗tanδ为0．10。     

铅含量对0-3型PZN-PZT/PVDF压电复合材料性能的影响

通过固相烧结法制备PZN-PZT压电陶瓷,采用溶液共混法将PZN-PZT陶瓷粉均匀分散于PVDF有机基体中,制备了PZN-PZT/PVDF 0-3型压电复合材料,测试并研究了材料的性能。实验结果表明,适量的铅过量可以有效抑制焦绿石相的生成,但含铅量过高会降低主晶相的结晶程度,从而影响最终制备的压电复合材料的性能。通过实验得出用Pb过量1.5%的压电陶瓷制备的压电复合材料的性能最好。     

热压法制备压电陶瓷／聚合物复合材料及性能研究

采用热压法分别制备了PZT／PVDF,PT／PVDF O-3型压电复合材料,所得材料具有较高的压电常数和良好的可柔性加工性能。并分析了无机压电陶瓷种类、含量对复合材料介电性能和压电性能的影响。     

热压法制备压电陶瓷／聚合物复合材料及其性能的研究

本文采用热压法分别制备了PZT／PVDF、PT／PVDF0-3型压电复合材料,并分析了无机压电陶瓷种类、含量对复合材料介电性能和压电性能的影响。结果表明：所得材料具有较高的压电常数和良好的可柔性加工性能。     

复合工艺对压电复合材料性能的影响

采用直接混合和溶液混合两种不同的复合工艺,将铌锌锆钛酸铅（PZN—PZT）压电陶瓷粉体分散于有机聚偏二氟乙烯（PVDF）基体中,制备了0—3型PZN—PZT／PVDF压电复合材料。研究了复合工艺对压电复合材料性能的影响。结果表明,采用溶液混合法能有效地改善陶瓷的分散性及复合材料的压电性,当陶瓷质量分数为90％时,压电复合材料的压电常数d33达到33．4pC·N^-1。     

PZT/PVDF体系压电复合材料的介电和压电性能研究

采用复合材料热压工艺,制备了0-3型PZT/PVDF(钛锆酸铅/聚偏二氟乙烯)压电复合材料。系统地研究了PZT体积分数对材料介电、压电性能的影响,并与Furukawa等人的理论预测进行了对比。结果显示在PZT体积分数为70％时,获得了性能优良的压电复合材料。在压电陶瓷高含量区,部分压电陶瓷颗粒相互联接,形成了类似0-3(1-3)型连通形式,获得了压电和介电性能优良的压电复合材料。     

压电陶瓷/聚氨酯智能阻尼复合材料的制备与表征

以热塑性聚氨酯弹性体为基材,压电陶瓷粉和导电石墨为功能相,制备了压电陶瓷/聚氨酯智能阻尼复合材料,并对其结构性能进行表征分析。结果表明,压电陶瓷粉添加质量份为20和40时,能得到具有较好分散性的压电陶瓷/聚氨酯智能阻尼复合材料;当压电陶瓷粉添加质量份为40时,tgδ峰值达到最大,说明制得的复合材料具有良好的阻尼性能;相对介电常数随着压电陶瓷粉添加量的增加而增加,当压电陶瓷粉质量份为40时,相对介电常数为15.06。热性能测定结果表明,加入压电陶瓷粉后,复合材料的软化点明显提高。     

(K0.5Na0.5)(TaxNb1-x)O3无铅压电陶瓷的性能特征

采用传统电子陶瓷制备工艺制备了(K0.5Na0.5)(TaxNb1-x)O3无铅压电陶瓷。研究了不同Ta含量下(K0.5Na0.5)(TaxNb1-x)O3陶瓷的晶相组成及性能特征。结果表明,(K0.5Na0.5)(TaxNb1-x)O3陶瓷在低Ta含量时形成单一斜方相固溶体,但Ta含量达到0.08mol后则有K6Ta10.8O30次晶相产生。随着Ta的加入,陶瓷的体积密度逐渐增大,居里温度(Tc)逐渐降低。当Ta含量为0.08mol时陶瓷具有良好的铁电、压电性能和介电稳定性能,其压电常数d33为76pC/N。     

Ca,Sr掺杂BNT-BT压电陶瓷结构与性能研究

采用传统的电子陶瓷制备工艺制备了一系列0.93Bi05Na05Tio3-0.07(Ba1-xAx)TiO3(简写为BNBAT100x;其中A=Ca,sr,x:0.02,0.04,0.06,0.08,0.10)陶瓷,研究了陶瓷的结构、介电、压电性能变化特征.XBD分析表明,陶瓷样品均形成了单一的钙钛矿结构固溶体.陶瓷的介电、压电性能受Ca,Sr含量的影响显著.所有陶瓷样品表现出弥散相变特征.当x<0.08时,BNBCT陶瓷的介电常数大干BNBST陶瓷,同时,BNBCT陶瓷室温介电常数在x=0.04时达到最大.而BNBST陶瓷此时具有最小的室温介电常数.陶瓷的压电性能受Ca,Sr含量的显著影响,当Ca含量为6mol%时,压电常数(d33)和平面机电耦合(kp)达到最大,分别为1 40.5 pc/N和1 9.7%.而当Sr含量为4mol%时,BNBST陶瓷的压电常数(d13)达到最大为1 39.8pC/N.此时平面机电耦合(kp)为1 8.9%.     

Sr掺杂BNT-BT压电陶瓷结构与性能研究

采用传统的电子陶瓷制备工艺制备了一系列0.93Bi0.5Na0.5TiO3-0.07(Ba1-xSrx)TiO3(简写为BNBST100x;x=0.02,0.04,0.06,0.08,0.10)陶瓷,研究了陶瓷的结构、介电、压电性能变化特征.XRD分析表明,陶瓷样品均形成了单一的钙钛矿结构固溶体.陶瓷的介电、压电性能受Sr含量的影响显著.所有陶瓷样品表现出弥散相变特征.BNBST陶瓷的压电常数随着Sr含量的增加表现出先增大后减少的趋势.同时,当Sr含量为4 mol%时,压电常数(d33达到最大,分别为139.8 pC/N.     

高d33PLZT压电陶瓷的制备及性能研究

制备了高性能的PLZT系列压电陶瓷,测量了其压电性能,探讨了掺杂、工艺制度对材料性能的影响,观察了材料的形貌及断口情况。     

BNBMT无铅压电陶瓷的制备及性能研究

本文采用新型溶胶-凝胶制粉技术和传统陶瓷生产工艺制备了0.93Bi0.5Na0.5TiO3-0.07Ba1-xMgxTiO3（简称BNBMT100x）体系无铅压电陶瓷,并对BNBMT陶瓷的晶相特征及其介电和压电性能进行了讨论。XRD分析表明,陶瓷样品均形成了单一的钙钛矿结构固溶体;Mg的加入对陶瓷的介电、压电性能有显著影响;陶瓷的铁电-顺电相变峰显著降低、展宽;介电损耗在室温至200℃范围内较平缓。当x=0.04时,机电耦合系数kp和kt最大,分别为16%和19%,压电常数d33值为111pC/N。     

Strength Evaluation of Piezoelectric Ceramics under Transient Thermal Environments

The strength of piezoelectric ceramics is analyzed for a plate suddenly exposed to an environmental medium of different temperatures. The admissible temperature jump the material can sustain is studied using the stress- and fracture-toughness-based failure criteria. The critical parameters governing the level of the transient thermal stress in piezoelectric ceramics are identified. Solutions are obtained for the maximum thermal shock that the plate can sustain without failure, under the conditions that (i) maximum local tensile stress equals the tensile strength of the ceramic, and (ii) maximum stress intensity factor for representative pre-existing cracks equals the fracture toughness of the ceramic.     

Cement-Based 0-3 Piezoelectric Composites

To meet the requirements of development for smart or intelligent structures in civil engineering, new functional materials that have good compatibility with civil engineering structural materials are needed. In this study, for the first time in the field of piezoelectric materials, cement-based 0-3 piezoelectric (PZT) composites were fabricated by the normal mixing and spreading method. The new materials have very good compatibility with portland cement concrete. The cement-based 0-3 piezoelectric composites were shown to have a slightly higher piezoelectric factor and electromechanical coefficient than those of 0-3 PZT/polymer composites with a similar content of PZT particles; thus, they are adequate for sensor application. There is potential for the application of cement-based 0-3 PZT composites in civil engineering because of their better piezoelectric properties and good compatibility with portland cement concrete.     

材料的压电性及压电陶瓷的应用

概述了材料的压电性，给出了压电方程式，并对压电陶瓷的结构、制备工艺、应用及前景做了阐述。介绍了压电陶瓷在换能器和压电振子上的应用，着重阐述了作为压电变压器使用时的原理和应用情况。     

Toughening of Glass by a Piezoelectric Secondary Phase

A toughening concept for glass, based on exploiting the ferroelastic effect of piezoelectric particles embedded in a glass matrix, is described. It is hypothesized that the domains within a piezoelectric phase will align themselves in the direction of the stress field around an advancing crack, thus absorbing energy and contributing to toughening. A powder technology route was optimized to fabricate lead-containing glass-matrix composites with up to 30 wt% of a lead zirconate titanate (PZT) particulate phase. An increase in fracture toughness of >50% was achieved via the addition of 30 wt% of PZT particles. Although other toughening mechanisms could be excluded in the present composites, the actual contribution of piezoelectric toughening remains under investigation.     

(1-x)BaTiO3-xKNbO3陶瓷的制备及性能研究

采用复合溶胶凝胶法制粉技术结合传统陶瓷制备工艺,制备了(1-x)BaTiO_3-xKNbO_3陶瓷,对其晶相特征、介电及压电铁电性能进行了研究。在1250℃下烧结的陶瓷形成了单一相的钙钛矿结构固熔体。介电常数随着KNbO_3含量的增加先减小后增加,KNbO_3的加入降低了陶瓷的介电损耗。样品的居里温度也在120℃之间波动。KNbO_3的加入使样品的压电常数d_33值逐渐减小。样品BT的d_33值最大,为140pC/N。样品的剩余极化强度(Pr)随着KNbO_3含量的增加而减小,由7μC/cm~2降为3μC/cm~2;矫顽场强(EC)随KNbO_3含量的增加呈现出变小的趋势,样品BT-KN10的矫顽场强(E_C)为4kV/cm。     

Fabrication and Evaluation of Porous Piezoelectric Ceramics and Porosity–Graded Piezoelectric Actuators

Porous ceramics of lead zirconate titanate (PZT) were prepared by sintering powder compacts consisting of PZT and stearic acid powders in an air atmosphere; stearic acid was added as a pore-forming agent (PFA). The dielectric, elastic and piezoelectric properties of uniformly porous PZT ceramics were investigated as a function of the porosity volume fraction. Furthermore, a beam-shaped PZT actuator sample with a graded porosity content across its thickness was fabricated by sintering PFA-graded powder compacts. The electric-field-induced bending displacement characteristics of the actuator samples were measured by using strain gauges and were found to be in good agreement with the theoretical predication based on a classical lamination theory.     

Dielectric, Piezoelectric, and Pyroelectric Properties of Lead Zirconate—Lead Zinc Niobate Ceramics

New piezoelectric and pyroelectric ceramics consisting of antiferroelectric lead zirconate (PZ) and relaxor ferroelectric lead zinc niobate (PZN) are studied from an application view-point of the field-induced antiferroelectric-to-ferroelectric phase transition. An antiferroelectric-ferroelectric phase boundary exists in PbZr_x(Zn_1/3Nb_2/3)_1−xO₃ (PZZN-1000x) close to x = 0.93 to 0.94 at room temperature. A new ferroelectric rhombohedral phase change, F_α–F'_α, at low temperature is found and studied by the temperature dependence of the pyroelectric coefficient. Electrical poling in these ceramics is easy, and the coercive field E_c∼8 to kV/cm is rather low. Samples with compositions in the range PZZN-86 to PZZN-92 have a large electromechanical coupling constant, k (k_t and k₁₅∼50% to 60%), and a low dielectric constant, ɛ_s (ɛ^T₃₃/ɛ₀= 260 to 320, ɛ^T₁₁/ɛ₀= 380). PZZN ceramics appear to be potential candidates for high-frequency ultrasonic transducers used in the thickness shear mode. The pyroelectric figure of merit (F_v) of these ceramics is comparable to the values published for the PZT-based or PbTiO₃-based materials.     

Piezoelectric and Magnetoelectric Effects of Flexible Magnetoelectric Heterostructure PVDF-TrFE/FeCoSiB

Flexible polymer-based magnetoelectric (ME) materials have broad application prospects and are considered as a new research field. In this article, FeCoSiB thin films were deposited on poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) substrate by DC magnetron sputtering. The structure of PVDF-TrFE/FeCoSiB heterostructure thin films was similar to 2-2. Under a bias magnetic field of 70 Oe, the composites have a dramatically increased ME voltage coefficient as high as 111 V/cm⋅Oe at a frequency of about 85 kHz. The piezoelectric coefficient of PVDF-TrFE thin films is 34.87 pC/N. The surface morphology of PVDF-TrFE thin films were studied by FESEM, and the results of XRD and FTIR showed that the β-phase of PVDF-TrFE thin films was dominant. Meanwhile, the effects of different heating conditions on the crystallization and piezoelectric properties of PVDF-TrFE films were also studied. The flexible ME heterojunction composite has a significant ME voltage coefficient and excellent piezoelectric properties at room temperature, which allows it to be a candidate material for developing flexible magnetoelectric devices.