关键词: K_(0.44)Na_(0.52)Li_(0.04)Nb_(0.86)Ta_(0.10)Sb_(0.04)O_3;压电陶瓷;掺杂

Abstract: The K_(0.44)Na_(0.52)Li_(0.04)Nb_(0.86)Ta_(0.10)Sb_(0.04)O_3+x mol;K_4CuNb_8O_(23)(0≤x≤2)(abbreviated as LF4-KCN) lead-free piezoelectric ceramics were fabricated by solid state reaction. The phase, microstructure, electric properties of the samples were characterized by XRD, SEM and Agilent 4294A impedance analyzer. XRD result shows that the phase of the sample transforms from tetragonal into orthorhombic with the increasing of KCN content. When x≥1, the trace amount of second phase K_6Li_4Nb_(10)O_(30) can be detected. SEM shows that the grain size of those materials decreases as the KCN content increasing, and the figure of the grain becomes clearly. There is another dielectric constant maximum value around 100 ℃, which is the phase transition from orthorhombic to tetragonal (T_(O-T)), while the curie temperature (TC) shifts to higher temperature. The KCN-doping has great influence on the electrical properties, the ceramic becomes "hardened", the piezoelectric constant (d_(33)), electromechanical planar coupling coefficients(kp), the dielectric constant(ε_r) and dielectric loss(tanδ) at 1 kHz decrease as the KCN content increasing. The mechanical quality factor (Q_m) and the density increases significantly.