PIEZOELECTRIC PROPERTIES OF CEMENT PIEZOELECTRIC COMPOSITES CONTAINING NANO-QUARTZ POWDERS

Author(s):  
Huang Hsing Pan ◽  
Wei-Ren Lin ◽  
Kuan Huang

In order to increase piezoelectric properties of 0-3 type cement piezoelectric composites (piezoelectric cement) developed for structural health monitoring, nano-quartz powders, as the replacement of cement matrix, were added into PZT/cement composites. The piezoelectric cement consists of 50% PZT and 50% cement by volume. Two gradations of PZT inclusions, single-grading and medium-grading, were chosen to fabricate the piezoelectric cement. Nano-quartz powders of 1% to 6% were added to form nano-quartz piezoelectric cement. Experimental results indicate that nano-quartz powders can reduce the porosity of piezoelectric cement. The single-grading piezoelectric cement (PSQ) with 4% nano-quartz powders and the medium-grading one (PMQ) with 2% have the lowest porosity. The maximum values on both piezoelectric strain factor d33 and relative dielectric constant εr always occur at the minimum porosity of nano-quartz piezoelectric cement. Both the PSQ and the PMQ have the optimum d33=104 pC/N. For the PSQ, 4% nano-quartz powders provide a 22% enhancement on thickness electromechanical coupling coefficient Kt. However, the effect of nano-quartz powders displays as less effective to the Kt of the PMQ due to non-uniform distribution of PZT particles. Nano-quartz piezoelectric cement has higher piezoelectric properties able to monitor and detect concrete structural health.

2011 ◽  
Vol 412 ◽  
pp. 285-289
Author(s):  
Yue Ming Li ◽  
Zong Yang Shen ◽  
Hu Liu ◽  
Zhu Mei Wang ◽  
Yan Hong

First, (K,Na)NbO3 (abbreviated as KNN) powders were synthesized by microwave hydrothermal method using Nb2O5, NaOH and KOH as raw materials. The effects of NaOH/KOH mole ratio and reaction temperature on the structure of KNN powders were studied systematically. Near spherical KNN powders of about 800 nm in diameter can be obtained at the optimized processing parameters as follows: NaOH/KOH mole ratio was 1.40/4.60, reaction temperature was 200 °C. Second, the ceramics were successfully prepared from the microwave hydrothermal synthesized KNN powders under 1090 °C for 2 h. This ceramic sample showed the enhanced piezoelectric properties such as piezoelectric constant d33=142 pC/N and planar electromechanical coupling coefficient kp=38%, in addition to other good properties as relative dielectric constant εr=426, Curie temperature Tc=410 °C, remnant polarization Pr=17.45μC/cm2 and coercive field Ec=1.41 kV/mm, indicating that microwave hydrothermal method can improve the properties of KNN ceramics high efficiently.


2020 ◽  
Author(s):  
Wei Liu ◽  
lehui zhang ◽  
Yu Cao ◽  
Jianhong Wang ◽  
Peikang Bai ◽  
...  

Abstract In this study, 3-3 type cement-based piezoelectric composites were prepared by casting Portland cement paste in porous lead zirconate titanate (PZT) ceramics, then the Polyvinylidene fluoride (PVDF) of N-Methylpyrrolidone (NMP) solvent with concentration of 50-200 mg/ml was utilized to modify the PZT-PC composites. The influence of PVDF concentration on the density, microstructure, dielectric, piezoelectric and electromechanical properties were investigated. The results indicate that the density of PZT-PC composites increased gradually with PVDF concentration for the increasing combined weight of PVDF with the composites. The introduction of PVDF has also contributed to the reduction of leakage current during the poling and testing process, which led to increased relative permittivity εr and longitudinal piezoelectric strain coefficient d33, while the dielectric loss tanδ and longitudinal piezoelectric voltage coefficient g33 demonstrated an opposite changing trend. Both the thickness electromechanical coupling coefficient Kt and planar electromechanical coupling coefficient Kp of the PZT-PC composites increased with PVDF concentration. The acoustic impedance (Z) of PVDF modified PZT-PC composites ranged from 6.89 to 7.65 MRayls, making it suitable for applications in the health monitoring of civil engineering.


2009 ◽  
Vol 66 ◽  
pp. 238-241
Author(s):  
Xiao Fang Liu ◽  
Hua Jun Sun ◽  
Ming Wei ◽  
C.X. Xiong

The Nb modified PZT piezoelectric ceramic was synthesized by conventional solid-state reaction, where all of different particle sizes had the same physical properties. 0-3 modified PZT/PVDF composites were formed by hot-pressing method. The particle size effect of modified PZT on the relative dielectric and piezoelectric properties of the composites were investigated. The relative dielectric constant εr, piezoelectric constant d33 and electromechanical coupling factor kp were higher in the composite containing larger PZT particle size. The microstructures of the composites were studied by SEM, the composite with the finer PZT particle size was more homogeneous, but larger particle size was easy to be contacted. In a high volume fraction particle-loaded composite, some piezoelectric ceramic particle appeared to be in contact, as in a 1-3 connectivity pattern. The larger particle size of modified PZT itself could be seen as the grain of modified PZT contact in a 1-3 connectivity pattern and easy to be contacted each other compared to the finer particle size in the composites, thus reducing the resistance of the composites and the poling process became effective, which led to higher properties. The optimal particle size of PZT is about 100μm, the Nb modified PZT/PVDF (volume fraction 70/30) composite show higher dielectric and piezoelectric properties than the others, εr=156.6, d33=69pC/N and kp=0.358.


2014 ◽  
Vol 1061-1062 ◽  
pp. 83-86
Author(s):  
Hong Wu ◽  
De Yi Zheng

In this paper, the effects of different sintering temperature on the microstructure and piezoelectric properties of Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3(PNZZT) ceramic samples were investigated. The Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 ceramics materials was prepared by a conventional mixed oxide method. In the period of the experiment, the relationship between crystallographic phase and microstructure were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM) respectively. The XRD patterns shows that all of the ceramic samples are with a tetragonal perovskite structure. Along with sintering temperature increased and the x is 0.03, the grain size gradually become big. Through this experiment, it has been found that when the x is 0.03 and sintered at 1130°C for 2 h, the grains grow well, the grain-boundary intersection of the sample combined well and the porosity of the ceramics decreased, an excellent comprehensive electrical properties of the Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 samples can be obtained. Its best electrical properties are as follows: dielectric constant (ε) is 1105, dielectric loss(tg) is 0.017, electromechanical coupling coefficient (Kp) is 0.287, piezoelectric constant(d33) is 150PC/N


2010 ◽  
Vol 123-125 ◽  
pp. 161-164
Author(s):  
Dong Yu Xu ◽  
Shi Feng Huang ◽  
Chao Ju ◽  
Zong Zhen Zhang ◽  
Xin Cheng ◽  
...  

Periodic and non-periodic 1-3 type cement based piezoelectric composites were fabricated by cut and filling technique, using P(MN)ZT ceramic as functional material and cement as matrix. The influences of periodicity of piezoelectric ceramic rods in the composites on electrical properties of all the composites were discussed. The results show that the non-periodic composites have larger dielectric factor and piezoelectric strain constant than those of the periodic composite. The impedance-frequency spectra analysis indicates that the non-periodic arrangement of ceramic rods can effectively restrict the lateral structural mode of the composite, accordingly reduces the coupling resonant between the thickness resonant mode and lateral resonant mode. The thickness electromechanical coupling coefficient of non-periodic composites is larger than that of the periodic composite. With increasing the non-periodic level of P(MN)ZT ceramic in the composites, the mechanical quality factor of the composites increases gradually. Therefore, 1-3 type cement based piezoelectric composites with different special abilities can be obtained by varying the periodic arrangement of P(MN)ZT ceramic rods in the composites.


Author(s):  
Howard A. Winston ◽  
Fanping Sun ◽  
Balkrishna S. Annigeri

A technology for non-intrusive real-time structural health monitoring using piezoelectric active sensors is presented. The approach is based on monitoring variations of the coupled electromechanical impedance of piezoelectric patches bonded to metallic structures in high-frequency bands. In each of these applications, a single piezoelectric element is used as both an actuator and a sensor. The resulting electromechanical coupling makes the frequency-dependent electric impedance spectrum of the PZT sensor a good mapping of the underlying structure’s acoustic signature. Moreover, incipient structural damage can be indicated by deviations of this signature from its original baseline pattern. Unique features of this technology include its high sensitivity to structural damage, non-intrusiveness to the host structure, and low cost of implementation. These features have potential for enabling on-board damage monitoring of critical or inaccessible aerospace structures and components, such as aircraft wing joints, and both internal and external jet engine components. Several exploratory applications will be discussed.


2010 ◽  
Vol 650 ◽  
pp. 103-108
Author(s):  
Yu Hua Feng ◽  
Tie Zheng Pan ◽  
Xiang Qian Shen ◽  
Hao Jie Song ◽  
Li Ping Guo

Piezoelectric ceramics with appropriate curie temperatures and high dielectric and piezoelectric performances are attractive for formations of ceramic/polymer piezoelectric composites. The PSZT ceramics with compositions of 0.98Pb1.0-xBaxTi0.48Zr0.52O3-0.02PbSbO3 (x=0.14~0.24) have been prepared by a conventional solid reaction process. The ceramic structures are analyzed by X-ray diffraction and the barium substitution leads to structural changes of the tetragonal and rhombohedral phases which constitute the perovskite PSZT ceramics, and lattice distortions. The curie temperature almost linearly decreases from 226 °C to 141 °C corresponding the barium content increases from 0.14 to 0.24 in the ceramics. The dielectric and piezoelectric properties are largely influenced by the barium substitution and when the barium content at vicinity of 0.22, the piezoelectric strain constant d33 exhibits a dramatic change. It is found that as the barium content around 0.22, the PSZT ceramic specimen is characterized with a low curie temperature Tc=156 °C, and satisfied dielectric and piezoelectric properties with the relative dielectric constant εr=5873, dielectric loss factor tanδ=0.0387, piezoelectric strain constant d33=578 pC/N.


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