Investigation of substrate and poling voltage effects on characteristics of piezoelectric (PZT) films and its diagnostic application on hot embossing process
| Autor: | Shao-Chung Cheng, 鄭卲中 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 A sol-gel method was utilized to fabricate the ceramic PbZrxTi1-xO3 (PZT) film in this thesis.The prepared PZT sol-gel was coated on various metal substrates, including copper (Cu), alumina(Al2O3), stainless steel (SS) and titanium (Ti). After thermal treatment, the films were polarizedunder various conditions. The characteristics of the fabricated films, such as crystallization, microstructure, dielectric constant and loss, had been measured by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and LCR meter. The fabricated PZT film was attached on themold of hot embossing machine for real-time diagnosis of polymer hot embossing process nondestructively and non-intrusively. From the results of experiments, the intensities of PZT (110) phases of films on the Al2O3 and titanium Ti substrates were better than those on the Cu and SS substrates. Comparing with the thermal expansion coefficients of these metal substrates, the thermal expansion coefficients of Al2O3 and Ti substrates were closer than other two substrates. It indicated that the metal substrates with thermal expansion coefficients similar with PZT film would result in the better crystallization. When compared with their dielectric constants and losses, the tendency was similar. For investigating the voltage effect during the poling process, the applied higher voltage would result in the better crystallization and dielectric characteristics of films. The fabricated PZT film was attached on the mold of hot embossing machine for carrying out the processes of mold closing, heating, pressing, holding, cooling and mold detaching. The ultrasonic technique was adapted to monitor the melting, holding and cooling processes of polymer plate (Polyproylene, PP) inside the mold. The results indicated that the ultrasonic velocity of polymer would vary with the mold temperature, and the phase change of polymer plate between solid and liquid would be monitored by ultrasonic velocity. When the mold temperature lowered than 85℃, the ultrasonic velocity entered into a stable state, indicating that the polymer plate was already solidified and further cooling may not be necessary. From this information, the hot embossing process could be reduced to lower down the cost and reach the process optimization. In this thesis, the effects of metal substrates and polling voltage on the characteristics of the PZT films during the fabricating process were investigated. The fabricated PZT film was applied on the real-time diagnosis of polymer hot embossing process for monitoring the phase change of polymer plate to reduce the cycle time, lower down the cost and optimize process. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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