掺杂La2O3对镁橄榄石瓷介电性能的影响

利用传统烧结工艺,制备了不同La2O3含量的镁橄榄石瓷,并研究了La2O3组份对材料晶相构成、晶粒、晶相以及介电常 数和品质因数的影响。结果表明,添加La2O3后,材料的烧结温度明显降低,并生成了新相La2Al24.4O39.6;随La2O3含量的增 加,材料显微结构发生了变化;材料的相对介电常数在0-20％围内近似线性增长,而材料的品质因数Q也有较明显的 变化。     

Ca掺杂钨镁酸铅陶瓷材料的制备及其介电性能

研究了Ca掺杂钨镁酸铅(PMW)陶瓷材料的合成、结构、烧结以及介电性能。结果发现：在Ca^2 摩尔分数小于15％时，能形成单相的PCMW钙铁矿相，结构由原来的斜方相向立方相转变。用二步合成法制备的样品容易致密烧结，气孔率比一步法制备的样品小。Ca的加入降低了材料的介电损耗，在频率为1MHz时，介质损耗达到了10^-4。当Ca^2 摩尔分数大于10％时，材料的Curie峰宽化显著，介电常数温度系数降低。     

二氧化锡不同掺杂方式对钛酸钡介电性能的影响

研究了二氧化锡不同掺杂方式对钛酸钡介电性能的影响。采用固相法制备出掺杂比例为2mol%SnO2&BaO、2mol%SnO2和4mol%SnO2三组不同方式SnO2掺杂钛酸钡样品。结果表明,两种掺杂方式对钛酸钡的作用效果截然不同,SnO2-BaO共掺杂会以BaSnO3的形式固溶入钛酸钡晶格,从而增大其介电常数,减小居里温度,同时介电损耗不会增大;SnO2单独掺杂则会引入Sn4+杂质离子,造成钛酸钡介电常数的减小以及介电损耗的增大,导致介电性能的劣化。     

锰掺杂对压电陶瓷介电性能的影响

采用传统的电子陶瓷工艺制备了高性能四元系压电陶瓷（PZN-PMS-PZT）。考察了不同剂量锰掺杂对压电陶瓷的室温介电常数（εTr)，介电常数温度谱以及居里温度（Tc)的影响。实验结果表明：随着Mn含量的增加，压电陶瓷的室温介电常数εTr减小；由于内偏置场的影响，居里温度Tc随锰含量的增加而增加。     

MnCO_3掺杂对BMN陶瓷结构及介电性能的影响EI北大核心CSCD

采用固相烧结法,探讨了MnCO_3掺杂降低Ba(Mg_(1/3)Nb_(2/3))O_3(BMN)烧结温度的机理,研究了MnCO_3掺杂量对BMN陶瓷微波介电性能的影响。结果表明,适量的MnCO_3掺杂可以促进烧结,有效降低BMN陶瓷的烧结温度,改善陶瓷的微波介电性能。当MnCO_3掺杂量为4%(质量分数)时,BMN陶瓷的烧结温度从纯相烧结时的1 550℃降低到1 250℃,表观密度ρ=6.36 g/cm^3,相对理论密度达到98.6%,并具有良好的微波介电特性:高相对介电常数ε_r=31.4,高品质因数与谐振频率的乘积Q·f=99 200 GHz(8 GHz),接近于零的谐振频率温度系数τ_f=3×10^(–7)/℃。     

Er^(3+)掺杂对立方焦绿石陶瓷结构与介电性能的影响EI北大核心CSCD

采用固相反应法制备(Bi1.5–x Erx Zn0.5)(Zn0.5Nb1.5)O7(BEZN,x=0、0.05、0.10、0.15、0.20、0.25、0.30)陶瓷,研究了Er3+替代Bi3+对(Bi1.5Zn0.5)(Zn0.5Nb1.5)O7(BZN)陶瓷结构与介电性能的影响。结果表明:当Er3+掺杂量x<0.15 mol时,样品为单一α-BZN相;当x≥0.15 mol时,出现第二相。用分子动力学计算Er3+分别进入A、B位的溶解能结果可知,此时Er3+可能已进入B位。随Er3+掺杂量增加,Er3+进入晶格,BEZN陶瓷密度从6.999 g/cm3减小到6.680 g/cm3,有明显细化晶粒作用。一定频率(1 MHz)条件下,峰值介电常数随Er3+掺杂量增加而减小,弛豫峰温度范围介电常数变化量Δε逐渐减小,即弛豫峰逐渐宽化和平坦。     

掺杂PZT压电陶瓷材料的研制

本文在介绍掺杂ＰＺＴ压电陶瓷材料制备及其性能测试基础上，总结出生产掺杂ＰＺＴ材料的最佳烧成条件，研究表明，本文所研制的样品已达到或超过压电点火材料的水平，但所选系统仍有潜力可挖，只要工艺合适，性能完全能再提高。     

Mn含量对Al掺杂PMN-PMS-PZT陶瓷介电性能的影响

采用传统的固相烧结法制备了Pb1.07[(Mn1/3Nb2/3)1/2(Mn1/3Sb2/3)1/2]0.08(Zr0.828Ti0.092)O3+x wt%Al2O3+y wt%MnO2(x=0.1,0.3,0.5,0.7;y=0.00,0.02,0.04,0.06,0.08,0.10,0.12)热释电陶瓷,在对不同组分Al掺杂PMNPMS-PZT陶瓷材料介电性能对比寻优的基础上,逐步增加Mn的含量,研究不同Mn增量下,对最优Al掺杂PMNPMS-PZT热释电陶瓷相结构、晶粒生长以及介电性能的影响。通过X射线衍射仪(XRD)分析显示Al掺杂PMNPMS-PZT陶瓷和在最优Al掺杂基础上增加Mn的含量都不会引入新的杂相,扫描电子显微镜(SEM)分析表明当x=0.30,适当增加Mn的含量,有助于陶瓷晶体的均匀致密,但一旦添加过量则又会产生不好的影响。实验结果表明:采用530℃排塑,烧结1190℃,保温2 h,当x=0.30,y=0.08时,PMN-PMS-PZT热释电陶瓷具有较好的相结构和介电性能,其中介电常数εr约为210,介电损耗tanδ约为0.16%,压电系数d33约为66.00 pC/N。     

锆元素不同掺杂方式对钛酸钡陶瓷介电性能的影响

研究了锆元素不同掺杂方式对钛酸钡陶瓷介电性能的影响.采用固相法制备出掺杂比例为1mol%的zrO<,2>-BaO和ZrO<,2>两种掺杂方式的钛酸钡陶瓷样品,对其进行多方面的表征.实验结果表明.ZrO<,2>-BaO掺杂与ZrO<,2>掺杂的钛酸钡晶格常数、介电性能会发生不同的变化,这是由锆元素不同掺杂情况对钛酸钡的作...     

SrCO3掺杂对BMT陶瓷结构及介电性能的影响

采用固相烧结法制备SrCO3掺杂Ba（Mg1/3Ta2/3）O3（BMT）微波介质陶瓷,研究SrCO3质量（下同）掺量w（SrCO3）=2%～8%对BMT微波介质陶瓷结构和介电性能的影响。结果表明：添加适量SrCO3可以促进烧结并在一定程度上提高BMT陶瓷体系的B位离子1：2有序度;当w（SrCO3）=6%时,陶瓷致密...     

锆钛酸铅（PZT）粉体合成的研究进展

锆钛酸铅（PbZrxTi1-xO3,PZT）陶瓷是一类重要的铁电、压电、介电材料,其粉体的相组成、化学组成、热稳定性和烧结活性影响着陶瓷制品的铁电、压电和介电性能。本文详细综述了合成PZT粉体的固相反应法和湿化学方法的发展现状,并对几种合成方法的特点进行了评介,为低温合成纯相PZT粉体和PZT一维纳米结构指出了可能的方法。     

Ferroelastic Properties of Lead Zirconate Titanate Ceramics

To increase the reliability of multilayer actuators, calculation of the mechanical stress inside the device during operation is important. This paper shows that the small-signal value of the elastic constant s is not sufficient to describe the complicated behavior of lead zirconate titanate (PZT) ceramics. Therefore, compressive strain and depolarization have been measured as a function of large-signal stress applied parallel to the poling direction. The nonlinear dependence of the strain and depolarization can clearly be explained by domain processes. Soft and hard PZT ceramics have been investigated. In hard PZT, domain switching appears at higher stresses than in soft PZT. Moreover, in hard PZT, the domains partly switch back during unloading. The critical stress (coercive stress) necessary for a domain-switching process shows a dependence on the Zr:Ti ratio that is quite similar to the dependence of the electric coercive field. The influence of an electric field applied parallel to the poling direction and superimposed on the compression experiment also has been examined. The coercive stress depends linearly on the electric field. The linear coefficient of this relation is given by the ratio of depolarization to compressive strain caused by domain switching.     

Piezoelectric Lead Zirconate Titanate Ceramic Fiber/Polymer Composites

Piezoelectric lead zirconate titanate (PZT) ceramic fiber/polymer composites were fabricated by a novel technique referred to as "relic" processing. Basically, this involved impregnating a woven carbon-fiber template material with PZT precursor by soaking the template in a PZT stock solution. Careful heat treatment pyrolized the carbon, resulting in a PZT ceramic relic that retained the fibrous template form. After sintering, the densified relic was backfilled with polymer to form a composite. Optimized relic processing consisted of soaking activated carbon-fiber fabric twice in an intermediate concentration (405-mg PZT/(1-g solution)) alkoxide PZT solution and sintering at 1285°C for 2 h. A series of piezoelectric composites encompassing a wide range of dielectric and piezoelectric properties was prepared by varying the PZT-fiber orientation and polymer-matrix material. In PZT/Eccogel polymer composites with PZT fibers orientated parallel to the electrodes, K = 75, d ₃₃= 145 pC/N, d _h= 45 ± 5 pC/N, and d _hg_h= 3150 × 10⁻¹⁵ m²/N were measured. Furthermore, in composites with a number of PZT fibers arranged perpendicular to the electroded surfaces, K = 190, d ₃₃= 250 pC/N, d _h= 65 ± 2 pC/N, and d _h g_h= 2600 × 10⁻¹⁵ m²/N.     

Analysis of X-Ray Diffraction Line Profiles of Lead Zirconate Titanate Using the Fourier Method

Lead zirconate titanate (PZT) powder was prepared by a solid state reaction. The X-ray line broadening produced in PZT powder was analyzed by the Fourier method to estimate particle size and microstrain. It was found that an increase of the annealing temperature caused the microstrain to decrease owing to an increase in particle size. The Scherrer formula used to calculate the particle size yielded considerably smaller values.     

Effects of Thickness on Piezoelectric Properties of Highly Oriented Lead Zirconate Titanate Films

Lead zirconate titanate (PZT) films were deposited on platinized silicon substrates by spin coating using PZT sols containing polyvinylpyrrolidone (PVP) as an additive. PZT films with a 60/40 composition and a thickness of up to 8 μm were fabricated by repeating the deposition process 15 times on highly oriented (100) and (111) seed layers with the same composition. The films grew well in the direction of the seed layers and had a uniform and smooth surface without any cracks. As the thickness of the films increased, the grain size remained almost the same, but the effective d ₃₃ value increased steadily. The thickness dependence of the piezoelectric properties was attributed to the residual stress of the films.     

Microwave Dielectric Properties of Antiferroelectric Lead Zirconate

The dielectric properties of ceramic lead zirconate and rutile are presented at microwave frequencies. Several techniques are required to span the frequency range from 100 Hz to 26 GHz, and rutile is utilized as a reference material to determine the consistency between measurement methods. A significant relaxation was seen for lead zirconate. At 10 GHz, the dielectric constant decreased 20% from the 1-MHz value of 160, and the dielectric loss increased by more than 3 times the low-frequency value of 0.007.     

Phase Characterization of Lead Zirconate Titanate Obtained from Organic Solutions of Citrates

Lead zirconate titanate (PZT) with several Zr/Ti ratios was prepared by the organic solution of citrates of the respective cations. The Rietveld method was applied to perform quantitative analysis of the coexisting phases. The ratio of tetragonal/rhombohedral phases increased with calcination temperature. For the composition where Zr/Ti = 53/47, the tetragonal quantity varied from 25% to 35% for temperatures ranging from 600° to 800°C. For the powder with Zr/Ti = 57/43, only the rhombohedral phase was observed after calcination at 700°C. For the powder with Zr/Ti = 49/51, only the tetragonal phase was observed after calcination at 800°C. The amount of tetragonal phase was controlled in Zr/Ti = 55/45 by seeding the powder with the tetragonal phase of PZT.     

Lead Zirconate Titanate Fiber/Polymer Composites Prepared by a Replication Process

The woven replication process was used to fabricate lead zirconate titanate (PZT)/polymer composites with 1–3, 2–3, and 3–3 connectivities by starting with novoloid-derived carbon fiber, woven fabric, and nonwoven felt templates, respectively. Activated carbon-fiber template material was impregnated with PZT by soaking it in a solution containing stoichiometric amounts of dissolved lead, zirconium, titanium, and niobium ions. Heat treatment burned out the carbon, leaving a PZT replica with the same form as the template material. Replicas were sintered in a controlled atmosphere and backfilled with an epoxy polymer to form final composites. This method, which is believed to be adaptable for mass production, is capable of producing composites with extremely fine microstructures. Woven composite samples have fiber tow diameters of 200 to 250 μm and spacings between tows of about 150 to 250 μm. Average d ₃₃= 90 pC/N, g ₃₃= 211 mV · m/N, and d_hg_h hydrophone figure of merit of 2100 × 10⁻¹⁵ m²/N values are reported for woven PZT/polymer composites.     

Low-Temperature Preparation of Nanocrystalline Lead Zirconate Titanate and Lead Lanthanum Zirconate Titanate Powders Using Triethanolamine

Nanocrystalline lead zirconate titanate (PZT) powders, with a Zr:Ti ratio of 60:40, have been prepared from a solution of triethanolamine (TEA) and Ti⁴⁺, Zr⁴⁺, and Pb²⁺ ions. The metal ions were in solution through complex formation with TEA. The soluble metal-ion–TEA complex formed the precursor material when it was completely dehydrated. Heat treatment of the precursor at 450°C resulted in single-phase PZT powders. The precursor and the heat-treated powders have been characterized by using thermal analysis and X-ray diffractometry (XRD) studies. The average particle size, as measured from X-ray line broadening and transmission electron microscopy studies, was ∼20 nm. PZT powders modified with 3 mol% of lanthanum (PLZT) also were prepared through this route and were investigated via XRD studies. The dielectric constants of the PZT and PLZT powders were 12475 and 11262, and their corresponding Curie temperatures were 362° and 315°C, respectively.     

Properties of Lead Zirconate Titanate Thick-Film Piezoelectric Actuators on Ceramic Substrates

Lead zirconate titanate (PZT) is a piezoelectric material that can sense or respond to mechanical deformations and can be used in ceramic electro-mechanical systems (C-MEMS). The microstructural, electrical, and piezoelectric characteristics of thick PZT films on low-temperature cofired ceramics (LTCC) and alumina substrates were studied. The PZT composition was prepared with low-melting-point additives in order to decrease the sintering temperature and to be compatible with thick-film technology. The integration of the PZT thick-film materials on ceramic substrates could lead to degradation of the PZT's characteristics due to the interactions between an active PZT layer and a substrate, particularly with glassy LTCC material. To minimize the interactions with LTCC substrates, an intermediate PZT barrier layer was integrated. The value of the piezoelectric coefficient d ₃₃ was found to be up to 120 pC/N on an alumina substrate and approximately 50 on an LTCC substrate. Based on these results, a cantilever-type actuator was designed and fabricated on alumina substrates. Under an applied voltage of 200 V, the maximum tip deflection was about 5 μm.