一种新型微致动元件的制作及特性研究

Study on Fabrication and Properties for a Novel Micro-actuated Element

介绍了一种用于计算机磁头精确定位的新型压电元件。该元件采用高速流延工艺制备Pb(Mg1/3Nb2/3)O3-Pb(Zr0.52Ti0.48)O3多层膜,由丝网印刷工艺制作Ag/Pd内电极。为优化元件的制作工艺,对流延过程作了DTA/TGA分析。结果显示,采用110℃、350℃和1090℃的三步烧结工艺可显著提高元件的钙钛化程度,从而提高其压电性能,减少内部缺陷。对元件的XRD分析显示,110℃和350℃时压电薄膜中以钙钛矿相为主,且存在大量的焦绿石相,当烧结温度达到1090℃时,焦绿石相的含量已经很少。SEM分析表明,与最终烧结温度1070℃相比,当烧结温度达到1090℃时元件的显微结构更为致密,内部缺陷更少。封装测试在多普勒干涉仪上进行,结果表明,该致动器具有优异的位移/电压灵敏度、谐振频率等特点。

A novel U--type piezoelectric micro--actuator for positioning a magnetic head for high --density hard disk devices had been fabricated and analyzed. This micro--actuator was made by using a high-- speed tape -- casting technique to deposit Pb （ Mg1/3 Nb2/3 ） O3 -- Pb （ Zr0. 52 Ti0.48 ） 03 （PMN -- PZT） multiplayer films and applying screen--printing processes to fabricate Ag/Pd electrodes. The formation mechanism of PMN--PZT ternary solid solution prepared by mixed oxides techniques had been characterized by differential thermal analysis （DTA） and thermal gravimetric analysis （TGA）. The reasonable co--firing process was composed of three steps： including co--firing at 110℃, 350℃ and 1090℃, respectively. The piezoelectric elements were investigated by XRD. The XRD analysis shows that many pyrochlore phase is formed in PMN--PZT films fired in PbO atmosphere at 110℃ and 350~C in addition to a perovskite phase, while a little pyrochlore phase is observed at 1090℃. PMN--PZT elements fired at 1090℃ show denser microstructure and lesser internal defects than those fired at 1070℃. After that, an U--type micro--actuator attached to each side via piezoelectric elements was also practically measured by laser Doppler vibrometer in order to testify the driving mechanics of it. The highest displacement/voltage sensitivity and corresponding resonance frequency are achieved by the micro--actuator.