Lead-free 0.94Bi0.5Na0.5TiO3–(0.06−x)BaTiO3–xK0.5Na0.5NbO3 (x=0–0.06) ceramics were prepared. All these compositions have a structure close to the rhombohedral–tetragonal morphotropic phase boundary (MPB) and good electric properties at room temperature. No significant composition dependence of ferroelectric property can be established, whereas a dependence of piezoelectric properties can be observed, e.g. the piezoelectric coefficient (d33), planar coupling factor (kp), and field-induced strain (S) increase with increasing x when x≤0.01 and then tend to decrease. The highest d33, kp, and bipolar strain are 118 pC/N, 0.29, and 0.32%, respectively, in the composition with x=0.01. The results not only indicate that BNT–BT–KNN lead-free piezoceramics can persist in the structure close to MPB in a wide composition range but that they may also be helpful for further investigation on lead-free piezoceramics.
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Document Type: Research Article
National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
EPCOS OHG, Corporate Materials R&D, Siemenstr. 43, 8530 Deutschlandsberg, Austria
Publication date: 2010-06-01