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Detailed Program
Paper Number : LP-P01
Time Frame : 12:00~13:30
Presentation Date : Friday, 28, November
Session Name : Leadfree Piezoelectrics
Session Chair 1# : -
Session Chair 2# : -
Effect of Sintering Temperature on Piezoelectric and Ferroelectric Properties of 0.99(0.67BiFeO3-0.33BaTiO3)-0.01Bi(Ni0.5Ti0.5)O3 Ceramics
Ms. IJ Hwang
Keimyung University
In order to replace lead-based piezoelectric ceramics such as Pb(Zr,Ti)O3 (PZT), a lot of efforts have been done to develop lead-free piezoelectric materials including the (Bi,Na)TiO3, (Bi,K)TiO3, (K,Na)NbO3 systems. Although remarkable improvement in piezoelectric properties of some complex systems was achieved, it is still unsuitable for high temperature applications. Recently, lead-free (1-x)BiFeO3-xBaTiO3 (BF-BT) ceramics have been introduced and exhibited Curie temperature (Tc) close to 600¢®É [1]. BF-BT has a morphotrophic phase boundary (MPB) with the coexistence of both rhombohedral and cubic phases near 67 mol% of BiFeO3. It can be expected a large piezoelectric coefficient near a MPB region in the BF-BT system, such as PZT. In this study, 0.99(0.67BiFeO3-0.33BaTiO3)-0.01Bi(Ni0.5Ti0.5)O3 (BF-BT-BNT) ceramics were studied. The BF-BT-BNT ceramics were prepared by a water quenching method after sintering instead of a traditional solid-reaction process. Sintering temperature dependences of crystal structure, piezoelectricity, and ferroelectricity of the ceramics were investigated. There was no significant change in the crystal structure depending on sintering temperature from 970 to 1020¢®É. The average grain size increased with increasing sintering temperature. It was found that the BF-BT-BNT ceramics sintered at 980, 990, and 1000¢®É showed better piezoelectric and ferroelectric properties than those of the BNT ceramics sintered at 970, 1010, and 1020¢®É. The piezoelectric coefficient (d33) and remnant polarization (2Pr) of the BF-BT-BNT ceramics sintered at 980, 990, and 1000¢®É were about 165 pC/N and over 50 ¥ìC/cm2, respectively. Also typical butterfly shaped strain-electric field loops were observed in the BF-BT-BNT ceramics. The Tc of the BF-BT-BNT ceramics was over 400¢®É. These results indicate that 0.99(0.67BiFeO3-0.33BaTiO3)-0.01Bi(Ni0.5Ti0.5)O3 ceramics can be a promising candidate for a high Tc lead-free piezoelectric material.
Acknowledgements :