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1.
Low-temperature processing and characterization of single-phase PZT powders by sol-gel method 总被引:1,自引:0,他引:1
Radhouane Bel Hadj Tahar Noureddine Bel Hadj Tahar Abdelhamid Ben Salah 《Journal of Materials Science》2007,42(23):9801-9806
A new sol-gel system using acetoin was developed and employed for the fabrication of PZT powders and films with compositions
near the morphotropic phase boundary Pb(Zr0.52Ti0.48)O3. Acetoin was used as chelating agent to replace the highly toxic methoxyethanol used in previous formulations. This route
simplified the chemical processing of PZT-based solutions. Powders were completely crystallized by about 450 °C and contained
the ferroelectric perovskite single phase. The firing temperature and time were to be the most important variables. Metallic
lead formed only when excess Pb was incorporated. 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,
was ∼35 nm. 相似文献
2.
Thomas R. Shrout Walter A. Schulze James V. Biggers 《Materials Research Bulletin》1979,14(12):1553-1559
Skinner, et al. prepared PZT/polymer composites using the coral replamine process. The composites were found to have, for certain applications, greatly improved electromechanical and physical properties over those of conventional piezoelectric materials. However, the coral replamine process requires natural coral from the ocean as the starting replica material, making this process industrially unfavorable.This paper discussed PZT/polymer composites electromechanically and physically comparable to the Skinner replamine composites. Fabrication is simplified by the use of a compacted mixture of volatilizable plastic spheres and PZT powder, which when sintered yields a piezoelectric with a density of less than 2.9 g/cm3, a permittivity of ~120 and a d33 of 180×10?12 C/N. The improved connectivity increases dh (hydrostatic) from ~35×10?12 C/N (solid PZT) to 100×10?12 C/N. 相似文献
3.
分别采用溶胶-凝胶法、超声-化学沉淀法、反相微乳液法合成了具有不同比表面积的纳米Al2O3粉体。采用TEM、HRTEM、SAED、XRD、比表面积分析等表征手段,分别对产物的形貌、结构、比表面积和孔容进行了表征和对比。纳米Al2O3粉体的比表面积为200~600m2/g(随合成方法和反应参数不同发生变化),均属γ-Al2O3,粒径均匀。考察了不同合成方法以及干燥方式对产物比表面积等物理性质的影响。结果表明,采用反相微乳液法结合真空冷冻干燥技术可以合成比表面积500m2/g的纳米Al2O3粉体。 相似文献
4.
采用醇盐水解工艺结合碳热氮化还原法进行纳米Al N粉末的制备。以异丙醇铝、果糖、无水乙醇为原料,制备出透明的凝胶,干燥后得到分子水平混合的前驱体,在1 450℃经碳热氮化还原法制备出单相Al N纳米粉末。系统研究了前躯体形成机制,以及碳热氮化还原的温度和时间、C/Al摩尔比、凝胶温度等因素对合成粉体的影响。采用XRD、TG-DSC和SEM对合成产物的特性进行了分析和表征。通过优化工艺,制得类球形的Al N粉末颗粒,其颗粒大小为30~90 nm。 相似文献
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7.
We propose a method for fabricating three-dimensional structures on GaAs surfaces using electron beam (EB) irradiation followed by wet chemical etching. An etch-resistant hydrocarbon layer forms on the GaAs surface with the EB irradiation. Structures can be fabricated after etching using the hydrocarbon layer to block the etching. The height dependence on the irradiation and etching conditions was investigated as a means of controlling the height of the structures. A higher structure was fabricated at higher doses. The etching selectivity changed with the concentration of the etchant. A three-dimensional structure was fabricated based on these results, demonstrating the possible use of this method as a novel three-dimensional fabrication method for GaAs surfaces. 相似文献
8.
Filomena Impero Martin Dix Antonino Squillace Biagio Palumbo Flaviana Tagliaferri 《Materials and Manufacturing Processes》2018,33(12):1354-1360
This paper compares conventional and cryogenic cooling in the deep hole drilling of carbon fiber reinforced polymer (CFRP)/Ti stacks. Various parameters are taken into account to find if the use of cryogenic coolant is justified by the improvement of the final results. Both the thrust and the torque were acquired continuously during the machining operations and compared both in average and distribution. The use of a cryogenic coolant brings a reduction in thrust force and torque without any sensible drawback. Overall the results prove that cryogenic drilling is a suitable technology for CFRP/Ti stack drill. 相似文献
9.
《Materials Letters》2007,61(8-9):1693-1697
CuS nanorods of length 60–100 nm and 15 nm in diameter have been synthesized by simple wet chemical method at 105 °C using CuCl2·2H2O as Cu-precursor, CS2 as S-source and ethylenediamine as the attacking reagent. The plausible reaction mechanism has been proposed and the effect of reaction temperature on morphology has been discussed. X-ray diffraction (XRD) pattern suggests the formation of hexagonal phase CuS. The morphology of the products has been studied by transmission electron microscope (TEM) analysis. A detailed optical study has also been done. 相似文献
10.
In order to optimize the chemical vapor deposition process for fabrication of carbon nanotube/Al composite powders, the effect of different reaction conditions (such as reaction temperature, reaction time, and reaction gas ratio) on the morphological and structural development of the powder and dispersion of CNTs in Al powder was investigated using transmission electron microscope. The results showed that low temperatures (500-550 °C) give rise to herringbone-type carbon nanofibers and high temperatures (600-630 °C) lead to multi-walled CNTs. Long reaction times broaden the CNT size distribution and increase the CNT yield. Appropriate nitrogen flow is preferred for CNT growth, but high and low nitrogen flow result in carbon nanospheres and CNTs with coarse surfaces, respectively. Above results show that appropriate parameters are effective in dispersing the nanotubes in the Al powder which simultaneously protects the nanotubes from damage. 相似文献
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12.
PZT薄膜厚度对BMT/PZT复合薄膜结构及介电性能的影响 总被引:3,自引:0,他引:3
采用液相旋涂法制备了Ba(Mg1/3Ta2/3)O3(BMT)/Pb(Zr0.52Ti0.48)O3(PZT)复合薄膜,研究了PZT薄膜厚度对BMT/PZT复合薄膜结构及介电性能的影响。随着PZT薄膜厚度的增加,BMT/PZT复合薄膜的介电常数呈线性增加。当PZT薄膜的厚度较小时,会明显地增加BMT/PZT复合薄膜的介电损耗;当继续增加PZT薄膜的厚度,介电损耗反而下降直到与BMT薄膜的介电损耗值接近。这是由于PZT的介电常数与介电损耗均明显高于BMT薄膜所致,而异质界面的存在抑制了PZT薄膜中畴壁的运动,使其对复合薄膜介电损耗的影响减弱。研究结果表明,PZT薄膜的引入可以提升BMT薄膜的介电常数而对介电损耗的影响不大。 相似文献
13.
The last two decades have witnessed the proliferation piezoelectric composite transducers for an array of sensor and actuator
applications. In this article, a concise summary of the major methods used in composite making, with special emphasis on Solid
Freeform Fabrication (SFF), is provided. Fused Deposition of Ceramics (FDC) and Sanders Prototyping (SP) are two SFF techniques
that have been utilized to make a variety of novel piezocomposites with connectivity patterns including (1-3), (3-2), (3-1),
(2-2) and (3-3). The FDC technique has also been used to prototype a number of actuators such as tube arrays, spiral, oval,
telescoping, and monomorph multi-material bending actuators. It has been demonstrated that SFF technology is a viable option
for fabricating piezocomposite sensors and actuators with intricate geometry, unorthodox internal architecture, and complex
symmetry. The salient aspects of processing of such composite sensors and actuators are summarized, and structure-processing-property
relations are elaborated on. 相似文献
14.
以乙二醇为溶剂,硝酸锆为锆源,采用改进的溶胶-凝胶法,通过优化工艺参数制备了纳米Pb(Zr0.52Ti0.48)O3(PZT).通过对工艺条件研究, 揭示了体系的凝胶化可通过升高温度和增加pH值来实现.通过对溶胶的红外光谱分析给出了溶胶、凝胶形成的机理.通过TG-DTA、XRD、SEM、TEM等手段对从凝胶到PZT纳米晶的生长过程及性能进行了表征.实验证明,改进后工艺简单易行,溶胶稳定,干凝胶在650℃热处理2h,获得较完整的钙钛矿型PZT,粒径约为50~100nm. 相似文献
15.
《材料与设计》2015
Cu/Fe multilayered laminated composite was fabricated by a repeated diffusion-rolling procedure. With diffusion bonding initially, thinner layer was fabricated by rolling, and this procedure was repeated. The evolution of structure and properties of Cu/Fe multilayered composite was investigated. The low inter-solubility interface was examined by using high angle annular dark field (HAADF) imaging mode in scanning transmission electron microscopy (STEM). The interfacial strength of Cu/Fe was enhanced by the plastic deformation after rolling. Parallelism of interfaces can almost be achieved when the thickness of layer is above 25 μm or total reduction ratio is lesser than 99%. An inter diffusion area with about 25 nm in width was present at the interface. HR-TEM and FFT investigations at the interface region revealed that disordered substitutional solid solution of Cu and Fe occurred during the procedure. 相似文献
16.
《Science and Technology of Advanced Materials》2002,3(2):217-224
A laminated piezoelectric bimorph actuator with a graded compositional distribution of PZT and Pt was fabricated, and its deflection characteristics were evaluated. Using experimentally determined compositional dependency of elastic and piezoelectric properties in the PZT/Pt composites, the modified classical lamination theory and the finite element method were applied to find the optimum compositional profile that will give a larger deflection and smaller stress, simultaneously. The miniature bimorph-type graded actuator that consists of a composite internal-electrode (PZT/30 vol% Pt) and three piezoelectric layers of different compositions (PZT/0–20 vol% Pt) were fabricated by powder stacking and sintering. The deflection of the actuator was measured using electric strain gages mounted on the top and bottom surfaces of the actuator. The deflection was found to strongly depend on the composition distribution profile. Under an applied electric field of 100 V m−1, the actuator with an optimum composition profile exhibited a curvature of up to 0.03 m−1, which is a satisfactory performance for this kind of actuators. The stress generated on actuation was estimated to be as low as 0.4 MPa, which is much smaller than those of conventional directly bonded actuators and will assure a long actuation life. 相似文献
17.
Kenta Takagi Shohei Yokoyama Ryuzo Watanabe Abdulhakim Almajid Minoru Taya 《Science and Technology of Advanced Materials》2013,14(2):217-224
A laminated piezoelectric bimorph actuator with a graded compositional distribution of PZT and Pt was fabricated, and its deflection characteristics were evaluated. Using experimentally determined compositional dependency of elastic and piezoelectric properties in the PZT/Pt composites, the modified classical lamination theory and the finite element method were applied to find the optimum compositional profile that will give a larger deflection and smaller stress, simultaneously. The miniature bimorph-type graded actuator that consists of a composite internal-electrode (PZT/30 vol% Pt) and three piezoelectric layers of different compositions (PZT/0–20 vol% Pt) were fabricated by powder stacking and sintering. The deflection of the actuator was measured using electric strain gages mounted on the top and bottom surfaces of the actuator. The deflection was found to strongly depend on the composition distribution profile. Under an applied electric field of 100 V m–1, the actuator with an optimum composition profile exhibited a curvature of up to 0.03 m–1, which is a satisfactory performance for this kind of actuators. The stress generated on actuation was estimated to be as low as 0.4 MPa, which is much smaller than those of conventional directly bonded actuators and will assure a long actuation life. 相似文献
18.
A. P. Singh S. K. Mishra D. Pandey Ch. D. Prasad R. Lal 《Journal of Materials Science》1993,28(18):5050-5055
A semi-wet procedure for the synthesis of single-phase Pb(Zr
x
Ti1–x
)O3 powders at 600 °C is described. The ultrafine powders so obtained do not exhibit tetragonal/rhombohedral distortions until they are sintered at higher temperatures. The morphotropic phase boundary (MPB) for these powders, which are chemically homogeneous, lies between x=0.52 and 0.53. For x=0.525, the rhombohedral and tetragonal phases coexist. 相似文献
19.
The preparation of BPSCCO-Ag composites by an innovative wet method is described, which allowed admixing of silver in the
form of a solution to the solution containing all other cations, and the decomposition of the organic matter in a mild and
reproducible way. The citrate route was used without the use of nitrates, ethylene glycol or other reticulating or complexing
agents. After drying, silver was found to be dispersed in the powder in metallic form. The powders were treated in an atmosphere
containing nitrogen oxides in order to reduce the carbon content. The powders so prepared were suitable for “powder in tube”
processing in that they were very reactive toward the 2223 formation and may contain only the desired phases: 2212, metallic
silver and Ca2PbO4 which, when present in excess, produce a flux that helps texturing and full phase conversion. Preliminary results on the
high-purity samples prepared by the powder in tube process show a steady increase of Jc, with the absence of a maximum of Jc with number of treatments, and high texturing of the powder inside the tube.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
20.
T. Kimura A. Takenaka T. Mifune Y. Hayashi T. Yamaguchi 《Journal of Materials Science》1992,27(6):1479-1483
Needle-like TiZrO4 powder was prepared by reacting TiO2 and ZrO2 in the presence of molten chloride (NaCI or KCI) or sulphate (Na2SO4 or Li2SO4). Either a single-phase TiZrO4 or a three-phase mixture (TiZrO4, ZrO2 and amorphous TiO2) was obtained from the chloride or sulphate system. Particle morphology was dependent on heating temperature and duration as well as salt species. Needle-like PZT powder was obtained by reacting needle-like TiZrO4 powder with PbO above 750 °C. The PZT powder obtained at 750°C was composed of both tetragonal and rhombohedral phases, indicating a wide compositional variation. An increase in heating temperature reduced the degree of compositional variation, but enhanced the deformation of needle-like particles. 相似文献