Papers by Keyword: Electromechanical Properties

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Authors: Ruksapong Kunanuruksapong, Anuvat Sirivat
Abstract: In our research, we investigated the electrorheological responses and dielectrophoresis force of the six elastomers at various electric field strengths and temperatures. For the electrorheological responses, the effect of temperature, between 300 and 370 K, on the storage modulus responses (ΔG′2kV/mm) and on the dielectric constants of elastomers were investigated under applied electric field strengths varying from 0 to 2 kV/mm. The acrylic elastomers (AR70, AR71, and AR72) have positive storage modulus responses and sensitivities with increasing temperature and dielectric constant. In the case of styrene copolymers (SAR, SBS, and SIS), the storage modulus responses and sensitivities increase and attain the maximum at the glass transition temperature of the hard segment. We studied the dielectrophoresis forces of the six elastomers by measured deflection distance under various electric field strengths (0–600 V/mm) and calculated the force from non-linear deflection theory of the cantilever. The results show that the dielectrophoresis forces of the six elastomers increase with increasing electric field strength. The acrylic elastomer AR71 had the lowest electrical yield point (75 V/mm) and it generated the highest force (389 μN at E = 600 V/mm). On the other hand, SIS had highest electrical yield point (400 V/mm) and it generated the lowest force (67 μN at E = 600 V/mm). The dielectrophoresis forces depend on many factors, such as dielectricity, conductivity, and storage modulus of the elastomers.
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Authors: Elena Dimitriu, Floriana Craciun, Marin Cernea, Rodica Ramer
Abstract: The behaviour of the dielectric and piezoelectric properties of doped PZT ceramics, with variable lead content, has been investigated from –50oC to room temperature. The PZT materials were prepared by the oxide technique and samples were sintered as pellets, at various temperatures. Niobium and lithium ions have been substituted for Ti4+, Zr4+ in the PZT matrix, and a small amount of Bi2O3 was added to cause A-position vacancies. The lead content in the four materials prepared varies in a narrow range, from 0.97 to 1.029 lead atoms, while the concentration of all other components are maintained constant. The microstructure of samples, evaluated by SEM technique and XRD analysis evidenced the presence of the tetragonal phase characteristic for the PZT 52/48. The dielectric and piezoelectric c onstants measured on poled samples depends on the sintering temperature, defects and domain walls, lead content.
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Authors: Micka Bah, Fabien Giovannelli, Frédéric Schoenstein, Guy Feuillard, Emmanuel Le Clezio, Isabelle Monot-Laffez
Abstract: K0.5Na0.5NbO3 (KNN) was manufactured by spark plasma sintering (SPS), which is a fast sintering method allowing to control the grain growth. Different samples of KNN are sintered with SPS at 920°C under 50 MPa for 5 minutes. High densities over than 97% are achieved. In order to make domain engineering, KNN crystals are grown by floating zone method. Stable molten zone is reached when oxygen or nitrogen gas flux is used, leading up to 50 mm length of crystals. High electromechanical coupling factor kt about 46 %, kp around 45 % and ε33S/ε0 of 253 are achieved for KNN ceramics poled at optimum electric field about 3 kV / mm. KNN crystal boule exhibits kt about 40 % against 34 % for KNN ceramic, both poled at 1 kV / mm. These results are promising to replace PZT for transducers applications.
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Authors: Alimorad Rashidi, M. Omidi, M. Choolaei, M. Nazarzadeh, A. Yadegari, F. Haghierosadat, F. Oroojalian, M. Azhdari
Abstract: In this paper a simple method is used for fabrication of vertically aligned carbon nanotube (VACNT) within the cylindrical pores anodic aluminum oxide (AAO) substrate. Electronic and mechanical properties of VACNT have been obtained after removing AAO substrate. Vertically aligned carbon nanotube shows very interesting electromechanical properties which can be used in CNT-based sensors to detect chemical analytical or physical properties such as temperature orpressure.
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Authors: Xin Cheng, Shuang Shuang Liao, Shi Feng Huang, Li Li Guo
Abstract: Sulphoaluminate cement and Lead Niobium-Magnesium Zirconate Titanate ceramic [P(MN)]ZT were used as matrix and functional phase respectively to fabricate 1-3-2 cement-based piezoelectric composites by dice and filling technique. The influences of base thickness on piezoelectric properties, electromechanical properties and acoustic impedance properties of the composites were discussed. The results show that as the base thickness increases, the piezoelectric stain factor d33 increases gradually, while the piezoelectric voltage factor g33 decreases. The planar electromechanical coupling coefficient Kp exhibits the trend of decrease, while the thickness electromechanical coupling coefficient Kt and acoustic impedance show the increasing trend. The mechanical quality factor Qm reaches the minimum (1.49) when base thickness is 2.00 mm. The results reveal that the 1-3-2 piezoelectric composite will be suitable for application by changing the base thickness.
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Authors: Xin Cheng, Dong Yu Xu, Li Li Guo, Shi Feng Huang
Abstract: 2-2 cement based piezoelectric composite was fabricated using sulphoaluminate cement and lead magnesium niobate-lead zirconate-lead titanate ceramic (P(MN)ZT) by dice-and-fill technique. The effects of composite thickness on dielectric, piezoelectric and electromechanical properties of the composite were analyzed, respectively. The results show that the increase of composite thickness will improve the piezoelectric strain factor d33 of the composite, while decreases the piezoelectric voltage factor g33 of the composite. The relative dielectric factor εr as well as the dielectric loss tan δ of the composite also increases with increasing the thickness. The electromechanical analysis results show that the thickness electromechanical coupling coefficient Kt of the composite increases obviously with decreasing the thickness, meanwhile the mechanical quality factor Qm of the composite shows the increasing trend, thus, the receiving piezoelectric transducers can be fabricated by decreasing the thickness.
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Authors: Zhuang Zhi Sun, Gang Zhao, Wen Long Song, Guang Li Zhang, Hong Shi Bi
Abstract: Recently, ionic actuator as a kind of artificial muscle has attracted great attentions according to their remarkable strain under low-voltage stimulation. Here, we investigated a biocompatible ionic polymer actuator, which consists of multi-walled carbon nanotubes (MCNTs) film as the double electrode layer and an electrolyte layer equipped with a chitosan polymer skeleton. As a result, we found it presented various electromechanical properties under the preparation factors of the different additive glycerol (0mL, 2mL, 4mL). The actuators with 2mL glycerol behaved a longer life bending (65 times), which was obviously surpassed by the others. Also, based on strain and stress testing, Young's modulus of the electrolyte presented a decreasing trend. In fact, the improvement was mainly due to the weakened inter-molecular hydrogen and the rotation molecular of the electrolyte film. Results show the additive inside the electrolyte is very effective to improve the performance of artificial muscle.
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Authors: Rong Fa Chen, Dun Wen Zuo, Yu Li Sun, Duo Sheng Li, Wen Zhuang Lu, Min Wang
Abstract: Strain films in the thin film resistance strain gauge are prepared by magnetron sputtering method. Some results concerning the electromechanical and structural properties of nichrome (Ni80Cr20 wt.%) thin films are presented. As compared to the well-known Ni-Cu (constantan) alloy film, which are widely used for manufacturing pressure and force sensors, nichrome (Ni80Cr20 wt.%) thin films exhibit gauge factor values of the same order of magnitude, but they are much more corrosion resistant and adherent to the substrate. The influences of composition and post-deposition annealing on the electrical resistance, temperature coefficient of resistance (TCR) and gauge factor of nichrome (Ni80Cr20 wt.%) thin films are discussed.
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