Enhancing Electrical Properties in NBT–KBT Lead-Free Piezoelectric Ceramics by Optimizing Sintering Temperature |
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| Authors: | Ya-Ru Zhang Jing-Feng Li Bo-Ping Zhang |
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| Affiliation: | State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China |
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| Abstract: | Conventional sintering of (Na1− x K x )0.5Bi0.5TiO3 (abbreviated as NKBT x , x =18–22 mol%) lead-free piezoelectric ceramics was investigated to clarify the optimal sintering temperature for densification and electrical properties. Both sintered density and electrical properties were sensitive to sintering temperature; particularly, the piezoelectric properties deteriorated when the ceramics were sintered above the optimum temperature. The NKBT20 and NKBT22 ceramics synthesized at 1110°–1170°C showed a phase transition from tetragonal to rhombohedral symmetry, which was similar to the morphotropic phase boundary (MPB). Because of such MPB-like behavior, the highest piezoelectric constant ( d 33) of about 192 pC/N with a high electromechanical coupling factor ( k p) of about 32% were obtained in the NKBT22 ceramics sintered at 1150°C. |
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