Microstructure and piezoelectric properties of lead-free 0.95(Na_(0.5)K_(0.5))NbO_3-0.05(Bi_(0.5)K_(0.5))Zr_(1-x)Ti_xO_3 ceramics

摘要

0.95(Na_(0.5)K_(0.5))NbO_3-0.05(Bi_(0.5)K_(0.5))Zr_(1-x)Ti_xO_3 (abbreviated as KNN-BKZT_x) ceramics were prepared by the conventional solid state method, and the effect of the Ti content on the surface morphology, crystalline structure, and electrical properties of KNN-BKZT_x. ceramics were mainly investigated. With the increase of Ti content, the temperature of the orthorhombic-tetragonal (O-T) phases transitions shifted to lower temperatures, and the O-T phase boundary of KNN-BKZT_x ceramics was identified in the composition with 0 ≤ × ≤ 0.3 at room temperature. It was considered that the piezoelectric properties of the ceramics were enhanced significantly owing to the more possible polarization states resulting from the coexistence of two phases. The ceramic with x - 0.2 exhibited optimum properties: d_(33) = 260 pC/N, k_p = 0.38, and T_c = 323 ℃.