Developments of Piezoelectric Actuators by Using Envirnmentally Gentle Lead-Free Piezoelectric

使用环保无铅压电材料开发压电执行器

基本信息

批准号：
15360352
负责人：
TAKENAKA Tadashi
金额：
$ 9.86万
依托单位：
TOKYO UNIVERSITY OF SCIENCE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Lead-free materials are recently demanded from the viewpoint of environmental protection. For example, the registration will be enforced in the EU as the draft Directives on Waste form Electrical and Electronic Equipment(WEEE), Restriction of Hazardous Substances(RoHS) and End-of Life Vehicles(ELV). Therefore, lead-free piezoelectric materials have been widely attracting attention as new materials in place of Pb-based Pb(Zr, Ti)O3 (PZT) ceramics. To replace PZT systems, it is necessary that required piezoelectric properties for various applications were divided and were developed the corresponding each application. For example, the perovskite type ceramics seem to be a suitable for actuators and high power applications. In this project, we try to develop piezoelectric actuators by using envirnmentally gentle lead-free piezoelectric ceramics. Candidate materials with the perovskite structure for lead-free piezoelectric ceramics are BaTiO3(BT), (Bi1/2Na1/2)TiO3(BNT), (Bi1/2K1/2)TiO3(BKT) … More and KNbO3(KN) etc. The desiable properties for piezoelectric actuators should show at least the piezoelectric strain constant, d33>300 pC/N and the Curie tempearature, Tc>200℃.Dielecric, ferroelectric and piezoelectric properties of a solid solution based on three components of BNT, BKT and BT, that is, x(Bi_<1/2>Na_<1/2>)TiO_3-y(Bi_<1/2>K_<1/2>)TiO_3-z BaTiO_3(x+y+z=1)[BNBKy:z(x)] are studied as a candidate for the actuator applications. BNT-based ferroelectrics usually have the second phase transition below 200℃ and show no piezoelectric activities above this temperature. In first year of this project, we had the best composition BNBK4:1(0.852) with d_<33>=190 pC/N and T_c=300℃ near the morphotropic phase boundary(MPB). However, the second phase transition temperature (T_2=120℃) is lower than that of our goal. In second year, we again tried to study the three component system. Finally the k_<33> and d_<33> are 0.474 and 140.2 pC/N for BNBK2:1(0.78) and more 0.462 and 127.9 pC/N for BNBK2:1(0.72), respectively. Temperature dependences of piezoelectric properties of the three-component solid solution ceramics display that piezoelectric activities keep up to higher than 200℃ with the higher second phase transition. This solid solution seems to be a superior candidate material for lead-free piezoelectric multilayer ceramic actuators. Less

最近从环境保护的角度要求无铅材料，例如，欧盟将强制执行废弃电子电气设备指令草案（WEEE）、有害物质限制指令（RoHS）和终端指令草案。因此，无铅压电材料作为替代Pb基Pb(Zr,Ti)O3(PZT)陶瓷的新材料受到了广泛的关注。 PZT系统，有必要将各种应用所需的压电特性分开并开发相应的每个应用，例如，钙钛矿型陶瓷似乎适合执行器和高功率应用，在这个项目中，我们尝试开发。采用环保无铅压电陶瓷的压电致动器具有钙钛矿结构的无铅压电陶瓷的候选材料是BaTiO3(BT)、 (Bi1/2Na1/2)TiO3(BNT)、(Bi1/2K1/2)TiO3(BKT) … More 和 KNbO3(KN) 等。压电执行器的理想性能至少应表现出压电应变常数，d33>300 pC/N和居里温度，Tc>200℃。a的介电、铁电和压电特性以BNT、BKT、BT三种成分为主的固溶体，即x(Bi_<1/2>Na_<1/2>)TiO_3-y(Bi_<1/2>K_<1/2>)TiO_3- z BaTiO_3(x+y+z=1)[BNBKy:z(x)] 作为执行器应用的候选材料进行研究，通常具有以下第二相变。 200℃，并且在该温度以上没有表现出压电活性。在该项目的第一年，我们在同形相界附近获得了最佳成分 BNBK4:1(0.852)，d_<33>=190 pC/N 且 T_c=300℃（ MPB），但第二年的相变温度（T_2=120℃）低于我们的目标。第二年，我们再次尝试研究三组分体系。最后，BNBK2:1(0.78)的k_<33>和d_<33>分别为0.474和140.2pC/N，而BNBK2:1(0.72)的k_<33>和d_<33>分别为0.462和127.9pC/N。三组分固溶体陶瓷显示压电活性保持在高于200℃，具有较高的第二相转变，该固溶体似乎是无铅压电多层陶瓷执行器的优质候选材料。