Development of Functionally Graded Piezoelectric Actuator for MEMS(Micro Electro Mechanical System) by Powder Process Technology

本研究的目的是针对压电驱动器在微机电系统（MEMS）中的应用，开发具有功能梯度微结构（FGM）的压电驱动器，该驱动器比传统的非FGM驱动器具有更高的机械可靠性。所得结果如下：1。通过在PZT压电板中引入PZT/Pt复合梯度结构或孔隙度梯度结构，可以逐渐改变PZT压电板中的电致应变。这些执行器没有发生疲劳破坏的粘接界面，并且可以电致弯曲变形。FGM压电作动器的弯曲位移特性取决于其组成轮廓，存在弯曲位移达到最大的最佳组成轮廓。此外，利用改进的层合理论可以很容易地预测出最佳的成分分布。更重要的是，具有最优成分轮廓的PZT/Pt复合梯度压电双晶片驱动器的弯曲位移与非梯度双晶片驱动器的弯曲位移几乎相同。因此，PZT/Pt复合梯度压电双晶片作动器在不降低弯曲位移特性的情况下提高了机械可靠性。另一方面，孔隙度分级的单晶片执行器表现出比非分级的单晶片执行器更差的弯曲位移特性。然后，利用改进的层合理论，尝试了改善弯曲位移特性的物性剖面设计。结果表明，在FGM单晶促动器中引入减小压电常数、增大弹性模量和介电常数的型线可以改善其弯曲位移特性。采用粉末加工技术可获得高开孔率、适合实现改善弯曲位移特性的型材设计的孔隙度梯度压电预制块。这意味着下一步可以通过渗透工艺制造具有更高弯曲位移和机械可靠性的FGM单晶执行器。少

The purpose of this research is to develop the piezoelectric actuator with functionally graded microstructure(FGM) that has a higher mechanical reliability than the conventional non-FGM actuator aiming at the application of the piezoelectric actuator to the micro electro mechanical system(MEMS). The obtained results are described as follows.1. The electrically induced strain in a PZT piezoelectric plate could be gradually changed by introducing compositionally graded structure of PZT/Pt or porosity-graded structure into a PZT piezoelectric plate. These actuators had no adhesive interface at which the fatigue failure take place, and could electrically make a bending deformation.2. The bending displacement property of the FGM piezoelectric actuator depended on the composition profile, and there existed the optimal composition profile that the bending displacement become the maximum. Moreover, the optimal composition profile could be easily predicted by the modified lamination theory.3. T … More he PZT/Pt compositionally graded piezoelectric bimorph actuator with the optimal composition profile exhibited nearly the same bending displacement as the non-graded bimorph actuator. Therefore, PZT/Pt compositionally graded piezoelectric bimorph actuator is estimated to have enhanced mechanical reliability without degradation the bending displacement characteristics. On the other hand, porosity-graded monomorph actuator exhibited a bending displacement characteristics that inferior to the non-graded unimorph actuator. Then, the profile design of physical properties for improvement of the bending displacement characteristics was attempted by modified lamination theory. As a result, it was predicted to be able to improve the bending displacement characteristics by introducing the profile with decreasing the piezoelectric constant and increasing the elastic modulus and the dielectric constant into the FGM monomorph actuator.4. The porosity-graded piezoelectric preform that have high open porosity and that is suitable for the achievement of the profile design for improvement of the bending displacement characteristics could be obtained by powder processing technology. This means that it is possible to fabricate the FGM monomorph actuator with the higher bending displacement and mechanical reliability by infiltration as a next process. Less