Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, powder milling process and electrode material

This paper details improvements of the d₃₃ coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the powder milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled powders were obtained from Morgan Electro-Ceramics Ltd. These powders were mixed with various ratios of lead borosilicate glass in the range of 5–20% by weight and an appropriate quantity of Electro-Science Laboratories (ESL) 400 solvent to formulate a screen printable thixotropic paste. The use of a polymer top electrode to reduce the number of firing cycles the PZT layer is subjected to was also investigated. The results show that the highest values of d₃₃ were obtained from the ball milled powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples. The samples printed with a polymer top electrode have shown an average increase of around 15% in the value of d₃₃.     

中性束注入器Tank充气特性对离子源放电的影响

利用对PV-10型压电阀定标实验,研究了中性束注入器Tank内补充气体的参数对离子源放电弧电流的影响,对比压电阀脉冲电源的脉宽和幅值,显示后者对Tank内补充气体量具有更显著的线性关系.据此进行的中性束注入器离子源放电实验结果表明,采用压电阀定标值计算获得的参数,可以稳定重复地获得最大放电脉宽达到400 ms的等离子体弧电流,为下一步向托卡马克装置注入高能中性粒子束奠定了应用基础.     

Dispersion relations for SH-wave propagation in periodic piezoelectric composite layered structures

Propagation behavior of horizontally polarized shear waves (SH-waves) in a periodic piezoelectric-polymeric layered structure is taken into account. The layered structures are consisted of piezoelectric thin films bonded perfectly with polymeric thin films alternately. The phase velocity equations of SH-waves propagation in the periodic layered piezoelectric structure are obtained for the cases of wave propagation in the direction normal to the interface and along the interface, respectively. Filter effect of this kind of structure and the effects of volume fraction and shear modulus ratio of piezoelectric layer to polymeric layer on the phase velocity are discussed in detail, respectively. One set of piezoelectric thin film--polymeric thin film multilayer system (PZT-5H piezoelectric ceramics--polythene) is chosen to show the numerical simulation, basic properties of SH-waves propagation in this particular structure are revealed.     

Diffuse transition and piezoelectric properties of Pb[(Zr1−xTix)0.74(Mg1/3Nb2/3)0.20(Zn1/3Nb2/3)0.06]O3 Ceramics

In this work, the piezoelectric ceramic system of Pb[(Zr_1−xTi_x)_0.74(Mg_1/3Nb_2/3)_0.20(Zn_1/3Nb_2/3)_0.06]O₃, 0.47≤x≤0.57, with composition close to the morphotropic phase boundary, was studied. From the results of X-ray diffraction and piezoelectric measurement, ceramics near x=0.51 were found at the morphotropic phase boundary (MPB) between the tetragonal and pseudocubic perovskite. The planar coupling factor (k_p=0.72) is high at compositions near the MPB, but the mechanical quality factor (Q_m=75) is low. The calculation of the diffuseness of phase transition shows that the region of phase coexistence of this system is broader than that of the ternary system.     

Repair of notched beam under dynamic load using piezoelectric patch

In this paper, the repair of a cracked beam under an external dynamic load employing the electro-mechanical characteristic of piezoelectric material to induce a local moment is presented. Conceptually, an external voltage is applied to actuate a piezoelectric patch bonded on the beam to effect closure of a crack so that the singularity at the crack tip under dynamic load may be decreased. Globally, this has the effect of altering the resonant frequency of the cracked beam towards that of the healthy beam, which is the criterion used for the repair. To demonstrate the repair methodology, a cantilever beam is used as an illustration, where the repair moment coefficient and the voltage required are mathematically derived. The relationship between repair moment coefficient, crack parameters and length of piezoelectric patch is investigated. The difference between the proposed repair criterion and an earlier published criterion for cracked beam under static load is also shown. A numerical example is used to study the effectiveness of the proposed repair methodology and its results are compared with those from 3-D finite element analyses using ABAQUS 6.4 as one means of verification.     

压电结构的有限元分析方法

提出了一种新的压电结构有限元分析方法，即压电薄板立体单元法。利用哈密顿原理推导出压电结构的变分方程，建立了智能结构的有限元动力方程。并以具有压电薄层的层合板为例进行了研究，证明了本文所用方法简单、正确     

水声换能器及其研究和发展

阐述了水声换能器和频响特性、指向性及不同尺寸和频率范围的换能器的多种不同的校准方法，就其优缺点进行了比较。并具体介绍我国自声学院声学所成立以来水声换能器在换能材料和声学无源材料、换能吕和基陈以及水下电声测量等3个方面的取得的研究和成果。介绍了在压电陶瓷、吸声材料、换能器各种基阵等方面取得的国内外领先成果和应用现状。最后给出我国水声换能器的发展方向及动态，对其发展前景作了展望。     

新型压电化学传感器的理论与应用研究

介绍了近年来在新型压电传感器方面的研究工作。液隔电极式压电传感器具有构造简单、使用寿命长的优点，能传感晶体表面质量及溶液粘度、密度、电导率、介电常数等信息。串联式压电传感器对溶液的电导率和介电常数有高灵敏的频率响应，而且具有极其优异的频率稳定性，其使用寿命可无限期地延长。压电光谱电化学技术可同时现场检测电极中有关电、光、质量三方面的信息。     

压电喷射点胶阀的喷射性能分析及实验研究

利用压电叠堆具有较好的响应特性和输出特性的特点,提出了一种新型压电驱动式喷射点胶阀.该喷射点胶阀主要由压电叠堆、杠杆式微位移放大机构、阀杆和喷嘴组成.对胶液实现喷射的条件进行了理论分析,并利用ANSYS软件对喷嘴重胶液流场进行仿真,得到了阀杆位移、胶液黏度和驱动气压对喷射点胶的影响规律,最后通过实验验证了理论分析和仿真的正确性.当胶液的黏度为2Pa·s时,获得的胶点最小直径为0.5mm,胶点一致性误差在6％以内.为电子封装业提供了更加高效和准确的点胶方法.     

表面弹性波OPCM传感器的标定

标定了一种被称为正交异性压电复合材料(OPCM)的声发射(AE)传感器.利用断铅信号作为声源,SR-15型AE传感器作为标准传感器,以比较法研究了OPCM的脉冲响应.在玻璃纤维板上重点研究了OPCM的正交异性特性--陶瓷项数量的影响及响应规律的描述.实验结果表明,该传感器适于探测表面弹性波,陶瓷项数达到30,正交异性显著,能够很好地减小噪声、边界回弹波等信号对诊断信号的干扰,有助于板类结构健康监测.