Doping Effects on the High-Anisotropy Materials and Their Applications on Piezoelectric Transformers
| Autor: | Chia-Hsin Chen, 陳嘉鑫 |
|---|---|
| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 It is essential for piezoelectric materials with large electromechanical coupling factor kt and small planar electromechanical coupling factor kp for the applications of piezoelectric transformers with thickness extension vibration mode. In general, lead zirconate-titanate (PZT) solid-solution-family ceramics not only have a large coupling factor kt for piezoelectric stiffened mode, but also have a large electromechanical coupling factor k31 and kp for piezoelectric unstiffened effect. However, Lead titanate (PbTiO3) family ceramics have large piezoelectric anisotropy, where kt is larger than 50﹪and kp is less than 5﹪, which can be utilized for the piezoelectric transformer applications. In this research, effects of calcium and cadmium dopants on the piezoelectric and dielectric properties of Sm-modified PbTiO3 ceramics have been investigated. Sm-modified PbTiO3 ceramics were prepared by conventional mixed-oxide methods. We successfully showed that Ca and Cd additives are helpful to obtain much higher thickness electromechanical coupling coefficient, kt, than that of conventional PbTiO3 based ceramics and still keep small planar electromechanical coupling coefficient, kp. Microstructural and compositional analyses of these doped ceramics have been carried out using XRD and SEM. Sm-modified PbTiO3 ceramics, doped with BiFeO3 (BF) and Ba(Cu0.5W0.5)O3(BCW), prepared by conventional mixed-oxide methods with sintering temperature at 1000℃-1200℃ have also been investigated. We found that these additives were helpful in lowing the sintering temperature. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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