0-3型(PZT,KTN)/P(VDF-TrFE)三相铁电复合材料的电学性能

以偏氟乙烯-三氟乙烯（P（VDF-TrFE））共聚物为基体,锆钛酸铅（PZT）铁电颗粒为功能相,钽铌酸钾（KTN）颗粒为增强相,制备了0-3型（PZT,KTN）/P（VDF-TrFE）三相铁电复合材料。利用SEM及EDAX技术,分析了复合材料的显微结构及PZT和KTN相的分布。测试了具有不同KTN 体积分数的复合材料的电性能。实验结果表明:PZT和KTN相的颗粒分布均匀,存在少量的团聚体;随KTN体积分数的增加,三相复合材料的极化漏电流I、介电常数ε_r和介电损耗tanδ增加,压电系数d₃₃降低,而热释电系数p₃先增加后降低,但其d₃₃和p₃均高于具有相同PZT体积分数的PZT/P（VDF-TrFE）两相复合材料。      

0-3型压电陶瓷-硫铝酸盐水泥复合材料的压电性能

采用压制成型法,以快硬硫铝酸盐水泥为基体制备了水泥基压电复合材料。分析讨论了极化工艺条件和PZT含量对水泥基压电复合材料压电性的影响。结果表明,较高的极化电场强度和较长的极化时间均有利于压电性能的提高,但当极化电场强度和极化时间达到4.0 kV/mm和45 min后,压电应变常数d₃₃趋于稳定; 随着PZT含量的增加,硫铝酸盐水泥基压电复合材料的压电应变常数d₃₃、压电电压常数g₃₃和机电耦合系数K_P、K_t均显著增大。当PZT质量分数达到85%时,K_P和K_t可达28.54%和28.19%。      

成型压力对0-3型锆钛酸铅/水泥压电复合材料的影响

以快硬硫铝酸盐水泥为基体,以锆钛酸铅(PZT)为功能相,用压制成型法制备出0-3型PZT/水泥基压电复合材料。分析成型压力对PZT/水泥基压电复合材料的压电性和介电性的影响,结果表明:不同粒径PZT颗粒作为功能相的水泥基压电复合材料,成型压力对其压电性和介电性有不同的影响。在30~90 MPa压力范围内,成型压力越大,PZT/水泥压电复合材料的压电应变常数d33和相对介电常数εr均显著提高,这是由于气孔率随压力增大而减少,而压电电压常数g33的变化则与功能相的粒径有关。机电耦合系数也有着不同的变化趋势,对于6μm和126μm PZT/水泥压电复合材料,其机电耦合系数Kt和Kp随压力增大缓慢下降,而对于430μm PZT/水泥压电复合材料则呈上升趋势。当压力达到150 MPa时,其压电性和介电性均急剧减小。     

0-3 型压电陶瓷/ 硫铝酸盐水泥复合材料的介电频率特性和铁电特性

以硫铝酸盐水泥为基体, 铌锂锆钛酸铅[ 0. 08Pb (Li_1/4 Nb_3/4 ) O₃ ·0. 47PbTiO₃ ·0. 45PbZrO₃ ] (简称PLN)压电陶瓷颗粒为功能体制备了0-3 型水泥基压电复合材料。利用X 射线衍射(XRD) 和扫描电子显微镜(SEM) 对水泥基压电复合材料的相组成和显微结构进行了分析和观察, 重点研究了水泥基压电复合材料的介电频率特性和铁电特性。结果表明, 压电陶瓷颗粒与硫铝酸盐水泥的水化产物结合良好; 随着PLN 含量的增加, 复合材料的介电常数ε_r 、剩余极化强度Pr和矫顽电场强度Ec均增大; 在40～100 kHz 频率范围内, 水泥基压电复合材料的介电常数ε_r均随频率的增大而迅速降低, 这主要受复合材料中的界面极化所影响, 高频时, 介电常数变化较小, 表现出良好的高频介电稳定性; 复合材料的电滞回线发生畸变的原因主要是PLN 压电陶瓷破碎成颗粒后, 本身存在许多缺陷, 且与水泥复合后存在许多界面气孔。      

1-3型水泥基压电复合材料的制备及性能

采用切割-浇注法, 以硫铝酸盐水泥为基体, 制备了1-3型水泥基压电复合材料。详细阐述了1-3型水泥基压电复合材料的制备过程; 研究了0.375Pb(Mg_1/3Nb_2/3)O₃-0.375PbTiO₃-0.25PbZrO₃压电陶瓷柱的宽厚比w/t对1-3型水泥基压电复合材料的压电性能、 介电性能和声阻抗的影响。结果表明: 压电陶瓷柱的宽厚比w/t对1-3型水泥基压电复合材料性能有很大影响, 随着w/t的增加, 其压电应变常数d₃₃、 机电耦合系数K_p与K_t、 机械品质因数Q_m、 介电常数ε_r和介电损耗tanδ均随着w/t的增加而减小, 而压电电压常数g₃₃值几乎不受w/t的影响。在压电陶瓷体积分数仅为22.72%的条件下, 调节压电陶瓷柱的宽厚比w/t至0.130, 可使复合材料的声阻抗与混凝土的声阻抗十分接近, 从而有效地解决了智能材料在土木工程中的声阻抗相容性问题。      

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℃。     

聚苯胺改性0-3 型PZT/ 聚氨酯复合材料的极化与电性能

以聚苯胺( PANI) 原位聚合改性聚氨酯( PU) 树脂为基体, 锆钛酸铅( PZT) 陶瓷为功能相, 制备了0-3 型压电复合材料, 研究了复合材料极化和电性能。结果表明: 适量PANI 能够有效地提高0-3 型复合材料的极化和压电性能。随着PANI 含量增加, 复合材料的压电系数d33和机电耦合系数kp 迅速增大。当PANI 体积分数为4 %时, 复合材料的d33 = 34 pC/ N , kp = 0.25 , 均达到最大值。复合材料的介电常数和介电损耗随PANI含量的增加而上升。      

PZT基NiTi SMA/PZT复合材料的组织结构及其压电性能研究

采用真空直流溅射法在PZT基体上沉积NiTi SMA薄膜,再经过晶化处理而制备出PZT基NiTi SMA/PZT复合材料.使用扫描电子显微镜观察复合材料试样的表面和界面组织结构.使用ZJ-3A型准态仪、Automatic LCR Meter4225测试复合材料的压电常数d33,机电耦合系数KP1,介电损耗tgδ,以考察NiTi SMA薄膜对PZT压电性能的影响.测试结果显示复合材料的压电常数d33,机电耦合系数KP相对于PZT均有提高,而介电损耗tgδ有小幅度降低.NiTiSMA薄膜与PZT基体之间的良好的界面结合结构及界面附近存在的源自膜/基材料间晶格差异的约束应力,有利于电偶极子的定向运动,保障了PZT基体压电性能的发挥.     

PZT基NiTi SMA/PZT复合材料的组织结构及其压电性能研究EI

采用真空直流溅射法在PZT基体上沉积NiTi SMA薄膜,再经过晶化处理而制备出PZT基NiTi SMA/PZT复合材料.使用扫描电子显微镜观察复合材料试样的表面和界面组织结构.使用ZJ-3A型准态仪、Automatic LCR Meter4225测试复合材料的压电常数d33,机电耦合系数KP1,介电损耗tgδ,以考察NiTi SMA薄膜对PZT压电性能的影响.测试结果显示复合材料的压电常数d33,机电耦合系数KP相对于PZT均有提高,而介电损耗tgδ有小幅度降低.NiTiSMA薄膜与PZT基体之间的良好的界面结合结构及界面附近存在的源自膜/基材料间晶格差异的约束应力,有利于电偶极子的定向运动,保障了PZT基体压电性能的发挥.     

振动真空方法对水泥基压电复合材料性能提高表征测试

为改善水泥基压电复合材料的密实度,提高材料性能和耐久性,该文提出一种基于振动真空共同作用的方法,制备水泥基压电复合材料,设置两组对照试验。以普通硅酸盐水泥为基体,以锆钛酸铅压电陶瓷PZT为功能体,用振动真空和纯真空方法结合切割-填充法制备出1-3型、2-2型PZT/水泥基压电复合材料.研究分析振动真空和纯真空下水泥基压电复合材料的压电性、介电性和机电耦合性能的变化规律。结果表明:采用振动真空方法所得到的试件,其压电应变常数d_(33)和相对介电常数ε_γ比纯真空方法得到的结果相对偏大,而相对应的压电电压常数g_(33)则偏小,压电性能更好。振动真空方法得到的试件,其串联谐振频率f_s和并联谐振频率f_p较纯真空方法得到的试件要更小,而K_p、K_t和Q_m的值都稍微更大,机电耦合性能更好。     

PZT-epoxy piezoelectric transducers: A simplified fabrication procedure

Composite piezoelectric transducers have been constructed by partially dicing PZT ceramics and back-filling with epoxy. Composites containing 10 to 70 volume percent PZT were prepared with several different rod diameters. Measured dielectric constants ranged from 200 to 1000, longitudinal piezoelectric coefficients d₃₃ from 200 to 350 pC/N, and hydrostatic piezoelectric coefficients d_h from 40 to 80 pC/N. Piezoelectric properties are compared with solid PZT and with 3-1 composites made by extrusion.     

Piezoelectric composites of PZT and some semi-crystalline polymers

Piezoelectric composites of PZT ceramics and several semi-crystalline polymers have been produced by embedding slender PZT rods (4 volume percent) in the polymers. The observed dielectric constants were considerably lower than that of pure PZT. The hydrostatic piezoelectric voltage coefficients of the composites were larger than PZT, even though the composite hydrostatic piezoelectric strain coefficients were lower. Composite figures of merit ranged from one-third to six times that of PZT.     

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.     

High piezoelectric and dielectric properties of 0–3 PZT/cement composites by temperature treatment

Temperature treatment of 0–3 type PZT/cement composites before polarization yielded high dielectric and piezoelectric properties in materials with 50% PZT inclusions by volume and 50% cement matrix. Specimens were treated at seven temperatures from 23 °C to 150 °C and then applied by a 1.5 kV/mm poling field. The dielectric loss of the composites reduces at higher pretreatment temperatures, shorting the trigger time. Temperature treatment increased the piezoelectric strain factor d₃₃, the relative dielectric constant ε_r and the piezoelectric voltage factor g₃₃ of PZT/cement composites, but did not affect significantly the electromechanical coupling coefficient K_t. Piezoelectric factors reach stable values after 70 days of aging, and samples that were not temperature pretreated reached stable values earlier. Specimens pretreated at 150 °C exhibit d₃₃ = 106.3 pC/N and ε_r = 477 on the 70^th aging day, almost two times greater than the composites without temperature treatment. The resonance frequency of the composites on the 70th day decreases with increasing temperature, with the exception of 150 °C. Temperature pretreatment can also improve the phase angle of the composites. In addition, the effect of curing time for PZT/cement composites is an important factor to dominate the feasibility of polarization.     

压电陶瓷粒度分布对锆钛酸铅/聚偏氟乙烯复合材料电性能的影响

将不同粒度的锆钛酸铅(PZT)陶瓷粉进行复配,制成不同粒度分布的PZT陶瓷颗粒,然后与聚偏氟乙烯(PVDF)复合制备不同PZT粒度分布的PZT/PVDF复合材料,研究了复合材料的介电性能和压电性能。结果表明,当陶瓷颗粒体积分数高达70%时,双峰分布复合材料的压电系数可达75 pC·N-1。这是由于双峰分布复合材料中大陶瓷颗粒保持了完整的钙钛矿结构,小陶瓷颗粒填充在大颗粒之间,陶瓷颗粒彼此联接,形成了更多的电-力耦合通道,有效地实现了压电效应的传递。大陶瓷颗粒完整的钙钛矿结构以及大、小颗粒的协同堆砌效应,提高了PZT/PVDF复合材料的电性能。     

Fabrication and properties of PZT-ordinary Portland cement composites

Lead zirconate titanate (PZT)-ordinary Portland cement (OPC) composites were fabricated using 40%, 50% and 60% of PZT by volume. The dielectric constants of the composites were found to be 139, 176 and 290 for composites containing 40%, 50% and 60% PZT respectively. Successful poling of the composites was achieved and the measured piezoelectric coefficient (d₃₃) of the composites increased with PZT content. Measured d₃₃ values for the composites with 50% and 60% PZT content were 26 and 42 pC/N respectively. These are very promising results with very high d₃₃ values for PZT-cement composites. Moreover, using this fabrication method it is possible to produce PZT-OPC composites with more than 50% PZT by volume and that these composites have good potential for use in structural applications.     

Characteristics of relaxor-based piezoelectric single crystals forultrasonic transducers

For ultrasonic transducers, piezoelectric ceramics offer a range of dielectric constants (K~1000-5000), large piezoelectric coefficients (d_ij~200-700 pC/N), and high electromechanical coupling (k _t≃50%, k₃₃≃75%). For several decades, the material of choice has been polycrystalline ceramics based on the solid solution Pb(Zr_1-xB_2x)O₃ (PZT), compositionally engineered near the morphotropic phase boundary (MPB). The search for alternative MPB systems has led researchers to revisit relaxor-based materials with the general formula, Pb(B₁,B₂)O₃ (B₁:Zn²⁺ , Mg²⁺, Sc³⁺, Ni²⁺..., B₂ :Nb⁵⁺ Ta⁵⁺...). There are some claims of superior dielectric and piezoelectric performance compared to that of PZT materials. However, when the properties are examined relative to transition temperature (T₃), these differences are not significant. In the single crystal form, however, Relaxor-PT materials, represented by Pb(Zn_1/3Nb_2/3)O₃-PbTiO ₃ (PZN-PT), Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) have been found to exhibit longitudinal coupling coefficients (k₃₃)>90%, thickness coupling (k_t)>83%, dielectric constants ranging from 1000 to 5000 with low dielectric loss <1%, and exceptional piezoelectric coefficients d₃₃>2000 pC/N, the later promising for high energy density actuators. For single crystal piezoelectrics to become the next generation material of ultrasonic transducers, further investigation in crystal growth, device fabrication and testing are required     

Transverse honeycomb composite transducers

Composites with 3-1 connectivity were fabricated by impregnating an extruded, sintered honeycomb configuration of PZT with epoxy. The composites had lower density (≈ 3000 Kg/m³) and lower dielectric constant (≈ 400) than that of solid PZT. The maximum piezoelectric d?₃₃ coefficient of the composites was 350 pC/N, and the maximum hydrostatic d?_h 220 pC/N. ?_h and d?_h?_h of the composites were an order of magnitude higher than that of solid PZT. Considering the symmetry and phase connectivity of the individual phases in the composite, an explanation is given for the improved piezoelectric properties of the composites.     

PZT/P VDF 压电复合材料的制备及其性能研究

用氧化物一步合成法制备了PZT 粉末, X 射线衍射测试结果显示, 它是Zr/T i 为52∶48 的纯四方钙钛矿型结晶相, 并用SEM 观察了PZT 粉末的形貌; 用热分析仪测试了PVDF 的固化温度; 在自制模具上采用模压/烧结工艺获得了六种含PZT 不同体积含量的PZT/ PVDF 复合材料; 对其介电性和压电性的测试表明, 随着PZT体积含量的增加, 电性能参数呈非线性增大, 当PZT 的体积份数超过70% 时, 介电常数E和压电常数d₃₃值迅速增加, PZT 体积份数达到90% 时, 其电性能参数与纯PZT 值接近, 但此时复合材料的脆性较大, 已没有实用价值。