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1.
Abstract

9 Al2O3·2B2O3 whisker was used to reinforce PZT95/5 type ferroelectric transitional ceramics. The relation between properties (including electric and mechanical properties) and whisker content was studied. Experiment results indicate: Composites with proper whisker content can keep electric properties almost as good as that of base material, while improve mechanical properties effectively. Whisker pulling and bridging play important roles in the process of reinforcing.  相似文献   

2.
Nb doped PZT films with Nb concentrations of 0, 5, 8 and 12 mol% are being processed via chemical solution deposition on platinized Silicon substrates. An original processing route including seed layer and additional PbO coating is presented whereby homogeneous, pyrochlore free microstructures with 111/100 texture are obtained. The temperature dependence of the dielectric constant shows diffuse peaks corresponding to the paraelectric to ferroelectric transition. The transition temperature is found to decrease from 325°C to 220°C with increasing Nb content. Nb is however found to lead to a substantial increase in the dielectric constant in comparison to non-doped PZT. The dependence of the dielectric constant on DC bias field is also reported. Strong asymmetries towards positive values both in the values of the dielectric constant and coercive fields are obtained at room temperature, and become replenished at 100°C. This is interpreted in terms of space charge effects on the pinning of domain walls. Furthermore, the loss tangent shows a relaxation peak which shifts to higher frequencies with increasing Nb content, and suggests that Nb-doping affects the dielectric properties of the interfacial layer. Finally, Nb addition is found to lead to slant hysteresis loops with lower remnant polarization and coercive field.  相似文献   

3.
The PZT thick film cantilever devices fabricated via MEMS process have much attraction because they are appropriate for biological transducer or sensor, resulting from their large actuating force and relatively high sensitivity especially in liquid. By means of resonance behavior, theoretical calculation and experimental verification of the PZT thick film cantilever devices have not been studied before. Accordingly, we focused on the sensitivity analysis and interpretation of the PZT thick film cantilevers in this study. Especially, the investigation for mass sensitivity of the PZT thick film cantilever is of importance for physical, chemical and biological sensing application. The PZT thick film cantilever devices were constructed on Pt/TiO2/SiN X /Si substrates using screen printing method and MEMS process. The harmonic oscillation response (resonance frequency) was measured using an optical laser interferometric vibrometer. The effect of cantilever geometry on the resonance frequency change was investigated. Compared with the theoretical resonant frequency change by mass loading, the experimental resonant frequency change of the PZT micromechanical thick film cantilever shows a variation of less than 2%. Mass sensitivities are estimated to be 30.7, 57.1 and 152.0 pg/Hz for the 400 × 380 μm, 400 × 480 μm and 400 × 580 μm cantilever, respectively.  相似文献   

4.
Abstract

A PZT actuator integrated onto cantilever structure was fabricated for high speed atomic force microscopy (AFM). Five different electrodes were used to investigate the effect of top electrodes on the adhesion and the electrical properties in the PZT capacitors. The PZT capacitors with RuO2 top electrodes exhibited the best characteristics of five electrodes. The tip deflection and the resonant frequency of the PZT actuator were 11 μim at 10 V and 79 kHz, respectively. The PZT actuator provided much better AFM image quality and imaging speed than those done by using the conventional bulk PZT tube scanner. The creep distortion in the AFM image was greatly improved by using the high speed PZT film actuator.  相似文献   

5.
The influence of complex dopants including donor and acceptor ions on microstructure and electrical properties of PZT (Zr/Ti = 53/47) ceramics was investigated. The prepared PZT ceramics modified with complex soft dopants, La+3 and Nb+5, showed that the piezoelectric properties were enhanced and stable with the compositional variations, which made it possible to establish the higher reliability and reproducibility of the piezoelectric performances. For 1.0 mol% La and 1.2 mol% Nb doped composition, the maximum value, k P = 0.66, was obtained. Unlike single element doping, the complex doping of both the donor and acceptor ions caused various compensation effects for the piezoelectric properties of the PZT ceramics. The improved piezoelectric properties, i.e., enhanced Q m with remaining higher k p , were obtained in the PZT composition complexly doped with La+3 and Fe+3. For 1.0 mol% La and 2.0 mol% Fe doped PZT composition, relatively high Q m and k p values of 580 and 0.53, respectively, were obtained. It was also shown that the PZT composition had the rather lowered dielectric constant, ε r = 800, and considerably low loss, tanδ = 0.003. By changing the dopants compositions, the properties can also be tailored over wider range.  相似文献   

6.
Abstract

PZT(52/48) thick films with Pb-based complex oxide (PCW) additive were prepared on Pt/TiO2/YSZ/SiO2/Si substrate by screen printing method. PCW addition and PZT sol application are performed to fabricate high density PZT thick film and to lower sintering temperature. With the increase of sintering temperature, electrical properties of screen-printed films were improved. Further, for the sol-gel treated thick films, the electrical properties were improved as compared to only screen-printed films. For the PZT-0.12PCW thick films with sol-treated and sintered at 900°C, the remanent polarization (Pr) was about 23.8 μC/cm2 at the applied filed of 150 kV/cm2, the dielectric permittivity (Ωr) was 1024 at the frequency of 100 kHz, and the piezoelectric coefficient (d33) was 339 pC/N at the applied pressure of 1 atm. Finally, the application of these PZT thick films to piezoelectric actuator is described.  相似文献   

7.
The effect of Nb and excess PbO on the structural and electrical properties of conventionally prepared Nb-doped PZT 65/35 ceramics has been studied in this work. It is found that, from excess PbO contents as high as 4 mol%, the solubility limit of Nb in PZT occurs below 4 mol%, while a secondary prevoskite-like phase develops in the dielectric system for a further increase of Nb content. The ferroelectric and piezoelectric properties (permittivity, ferro-paraelectric phase transition, polarization, electromechanical coefficients) of such materials are thus found to be strongly dependent on the degree of densification and structural phase development during sintering at high temperatures. In particular, the nature of the ferro- to para-electric phase transition is in these materials noted to better fit a generalized rather than Smolenskii-Isupov equation, the former being appropriate for the characterization of non-purely diffuse transitions. In nice agreement with the Bokov model, substitution of Nb5 + for (Zr,Ti)4 + is found to induce only poorly diffuse phase transition in these materials. The electrical properties reported in this work are in magnitude comparable to those exhibited by PZT-based materials.  相似文献   

8.
新型银基导电陶瓷复合电接触材料   总被引:4,自引:1,他引:4  
针对目前触点材料领域的现状和存在的问题及低压电器对触点材料的应用要求,提出了一种研究触点材料的新思路,制成了银基导电陶瓷触点材料。实验结果表明,该材料具有优良的机械性能和电性能,完全可能成为AgCdO的替代品,同时其优良的机加工性能对AgSnO也具有很大的挑战性。  相似文献   

9.
在不同烧结温度下制备了氧化铝(Al2O3)掺杂的氧化锌(ZnO)压敏电阻,并对其进行扫描电子显微镜、X射线衍射、电流-电压、电容-电压测试以研究ZnO压敏电阻的微观结构和电气特性。结果表明:随着烧结温度的升高,Al2O3掺杂的ZnO压敏电阻泄漏电流得到了明显的抑制,这是由于施主密度和界面态密度不断增大,提高了晶界的势垒高度。而Al3+随着烧结温度的升高会不断地固溶入ZnO晶粒中,降低了晶粒电阻率,从而降低ZnO压敏电阻在通过大电流时的残压比。当烧结温度为1 150℃时,ZnO压敏电阻的电气特性最佳,电压梯度为418.70 V/mm,泄漏电流为0.74,残压比为1.68,非线性系数为67.5,有助于提高ZnO避雷器的保护性能,实现深度限制电力系统,特别是特高压系统的过电压。  相似文献   

10.
PZT thin films and interlayers were fabricated by the radio frequency (r.f.) Magnetron-sputtering from the Pb1.1Zr0.53Ti0.47O3, PbO and TiO2 target. As a result of the XPS depth profile analysis, we can confirm that the substrate temperature affects the oxidation condition of each element of interlayers and the PZT film. Compared to the PZT/Pt structure, the dielectric and pyroelectric properties of PZT thin films inserted by interlayers were measured to a relatively high value. In particular, the PZT/PbO structure had the highest pyroelectric properties (P = 189.4 μC/cm2K; F D = 12.7×10−6 Pa−1/2; F V = 0.018 m2/C).  相似文献   

11.
冰灾对运行复合绝缘子性能影响研究   总被引:1,自引:0,他引:1  
湖南是一个冰冻重灾区,冰冻灾害给电网的安全运行带来巨大危害,如大量的断线、掉串等.本文通过对运行复合绝缘子在冰冻灾害前后的机电性能试验研究,认为冰冻灾害前后复合绝缘子机电性能无明显变化,不存在遗留隐患,仍然能安全稳定运行,并提出在重冰区宜采用间插特大伞裙设计的防冰型复合绝缘子.  相似文献   

12.
Abstract

Ferroelectric PZT/PLZT thin films have been fabricated using the metallo-organic precursor compounds. The structural development, spectroscopic and dielectric properties of these films have been investigated using atomic force microscopy (AFM), X-ray diffraction, Raman scattering and dielectric measurements. Experimental results show that Raman spectroscopy is an effective tool of monitoring the structural development of the small sized PZT films in the tetragonal phase field. Dielectric characteristics have been improved by the rapid thermal processing approach. A rosette growth model is proposed to explain the observation of the tri-intersection of the perovskite phase in PZT films.  相似文献   

13.
A Pb0.98Eu0.02(ZryTi1−y )0.995O3 compound series, with y = 0.60, 0.53 and 0.45 was prepared. PZT samples were synthesized by sol–gel technique. The crystallization and quality of the compounds were analyzed by powder X-ray diffraction and electron microscopy. The shape of the ε′(ω) vs T curves can be considered typical of a ferro-paraelectric transition. The ferro-paraelectric transition temperature for each composition was 348, 328 and 307°C, for the y = 0.45, 0.53 and 0.60, respectively. σ′(ω) is strongly influenced by short range processes. For the logσ′(ω) curves as function of temperature, there is evidence of a non dispersive dc-conductivity component for the high temperature region. The associated dc-activation energies are larger than those calculated for the ac region (at lower temperatures).  相似文献   

14.
Abstract

Bi2(Zn1/3Nb2/3)2O7, BiZN, materials possess high dielectric constant and low loss factor in microwave frequency region. They have good potential for device application, especially in the form of thin films. However, the microwave dielectric properties of a thin film are very difficult to be accurately measured. Evaluation on the dielectric behavior of the films through the performance of the microstrip line devices made of these films involves metallic conduction and stray field losses. A novel measuring technique, which can directly evaluate the microwave dielectric properties of a thin film is thus urgently needed.

In this paper, BiZN thin films were grown on [100] MgO single crystal substrates using pulsed laser deposition process. The high-frequency dielectric properties of thus obtained thin films were determined using optical transmission spectroscopy (OTS). The [100] preferentially oriented films with pyrochlore structure can be obtained for the thin films deposited at 400–600°C substrate temperature under 0.1 mbar oxygen pressure. OTS measurements reveal that the index of refraction (n=1.95–2.35) and absorption coefficient (k=0.28x10?4-2.25 × 10?4 nm?1) of the films vary insignificantly with the crystallinity of the BiZN films.  相似文献   

15.
We examined the electrical properties of polylactic acid (PLA) with a nucleating agent added. The PLA with added nucleating agent was then heat‐treated at 100 °C for 30 seconds. The crystallinity of the PLA with added nucleating agent increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependence of the conductivity (σ) was investigated; at temperatures higher than 60 °C, σ of PLA to which the nucleating agent had been added showed a tendency to become lower than σ of PLA to which no nucleating agent had been added. The temperature dependence of the dielectric breakdown strength ( ) was investigated. of the PLA with added nucleating agent was about 5.0 MV/cm at 25 °C. Of particular note was the fact that the of PLA with added nucleating agent was about 4.7 MV/cm at 100 °C, which is about 3 times the value for PLA with no added nucleating agent. The temperature dependence of the relative dielectric constant (?r) and the relative dielectric loss factor (?r) was investigated. The peak dielectric absorption value of ?r for the PLA to which nucleating agent had been added showed a tendency to be lower than that of the PLA to which no nucleating agent had been added. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 25–31, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21293  相似文献   

16.
Development of sodium-immersed-type Electromagnetic Pumps (EMP) is expected to improve reliability, safety, maintainability, and construction cost of the Fast Breeder Reactor (FBR) compared with the conventional mechanical pumps. To realize the EMP, establishment of a high-temperature-resistant electrical insulating system is indispensable. A mica-alumina combination is selected for the insulating system at temperatures higher than 500°C. Using this insulating system, an aging pretest was performed. The aging condition was to apply 1.5-kV ac voltage in the nitrogen atmosphere at 550°C for 4000 hours. The dielectric properties before and after the aging were measured to understand the tendency of temporal change in the aging. In this result, the dielectric performance after aging was improved compared with the initial performance. The curious phenomenon was clarified to be caused by a decrease of organic component in the insulation, which remained due to incomplete burning. Also, the possibility of thermal runaway was considered to be higher as a dielectric breakdown mechanism.  相似文献   

17.
探索在智能化大楼中多子系统统一在信息集成平台下的可行性,除实现消防报警联动控制的全部功能外,还实现了相关设备如空调机组,生活泵、照明等协调运行,能更加有效地进行管理,且提高了设备利用率与管理效率。  相似文献   

18.
Abstract

Ferroelectric Bi2GeO5 glass-ceramics were fabricated using conventional and incorporation method. Glasses have been prepared from BiO1.5-GeO2-BO1.5 ternary glass system by focusing on the region of 59?mol%BiO1.5: 23?mol%GeO2: 18?mol%BO1.5. The resulting glass was analyzed by using differential thermal analysis (DTA) for determining the crystallization temperature (Tp). Then, the prepared glass pieces were heat treated at Tp. Effects of different fabrication methods on structure and electrical of the glass-ceramics were investigated. X-ray diffraction result of all glass-ceramics suggested that the main peak of glass-ceramics matched the orthorhombic structure of the pure Bi2GeO5 phase. Microstructures of the prepared glass-ceramics have been found to change from rod-like crystallites to bulk crystallites on modifying the fabrication method. The Bi2GeO5 glass-ceramics prepared by incorporation method presented higher dielectric constant than those of the Bi2GeO5 glass-ceramics prepared by conventional method. Moreover, the Bi2GeO5 glass-ceramic prepared by incorporation method possesses a large value of Pmax (0.94 µC/cm2) comparing to that of the glass-ceramics prepared by conventional method (Pmax = 0.73 µC/cm2). Thus, this study suggests that the incorporation method can effectively modify the microstructure of Bi2GeO5 glass-ceramics, resulting in the improvement of dielectric and ferroelectric properties.  相似文献   

19.
电磁性能和板形是无取向电工钢的重要产品特性,卷取温度作为生产控制中一个重要的工艺参数,对它们有重要影响。本研究通过大生产实验,发现高温卷取、U形卷取的层流冷却方式可以有效促进晶粒长大和均匀热轧带钢组织,并进一步提高无取向电工钢的电磁性能,但是会增大带钢纵向厚度的波动,对带钢横向厚度的控制无显著影响。  相似文献   

20.
FuYuanchu 《电气》2005,16(2):27-29
The hydropower installed capacity in China exceeded 100GW by the end of 2004. With the development of hydropower construction cause, the contingents of eleetrical and mechanical installation also grew steadily.The installation and debugging techniques made great strides in aspects of different conventional hydrogenerator sets. reversible pumped-storage units and their rotor spiders, runners, bearings, penstocks as well as control equipment, such as computerized governors, intelligent monitoring devices. Major technical innovations were brought about in the electrical and mechanical installation. For an arduous task to construct hydropower projects of over 50 GW confronts hydropower installatinn enterprises at the beginning of 2 I st century, the installation technologies will certainly develop around the projects.  相似文献   

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