| 초록 |
During recent years, energy harvesting from the environment has attracted more interest, particularly as micro power sources. Lead zirconate titanate (PZT) is a perfect candidate for harvesting power from ambient vibration sources because it can efficiently convert mechanical strain to electrical charge. Numerous studies concerning the piezoelectric harvester were performed either by modifying fabrication technique or by dopants. This paper proposes a composition and synthesis method for piezoelectric ceramic “PZT” employed in energy harvesting system. In this respect, Pb(Zr0.53Ti0.47)O3 and BiYO3 (BY) were pre-synthesized and then mixed to synthesized 0.99Pb(Zr0.53Ti0.47)O3-0.01BiYO3 [PZT-BY] using high energy mill (HEM). In addition, same composition of PZT-BY was also prepared by conventional ball milling process to compare it with HEM process. The HEM process of the starting materials lowered the calcination temperature to the extent of 150ºC as compared with conventional process. The HEM process improved the reaction activity and homogeneity of the materials used throughout the process, accompanying the enhancement of the sintering density, grain uniformity, and the decrease of grain size. In order to investigate the effects of the HEM process on the electric properties; phase structure, microstructure, ferroelectric and piezoelectric properties of PZT-BY ceramics were systematically investigated. The optimal sintering temperature was found to be 1040ºC. It was found that the modified method uses HEM, showing a high piezoelectric constant (d33) of 315 pC/N and electro-mechanical coupling factor (kp) of 63% with low dielectric constant (K33T) of 684 compared with 280 pC/N, 56% and 710 respectively, in the conventional process. In addition, piezoelectric voltage constant (g33), and transduction coefficient (d33 × g33) of PZT-BY ceramic has been calculated for both processes. The nano-sized PZT-BY shows considerably lower K33T value, but higher d33 and kp. Therefore, the maximum (d33 × g33) of 16,568 × 10-15 m2/N was obtained for nano sized PZT-BY. The large (d33 × g33) indicates that the PZT-BY ceramic fabricated by HEM process is a good candidate material for energy harvesting devices. |
