Effect of Bi_(0.5)(Na_(0.9)K_(0.1))_(0.5)TiO_3 on Phase Structure and Electrical Properties of (K_(0.5)Na_(0.5))NbO_3 Lead-free Ceramics

摘要

(1-x)(K_(0.5)Na_(0.5))NbO_3-xBi_(0.5)(Na_(0.9)K_(0.1))_(0.5)TiO_3 ((1-x)KNN-xBNKT) lead-free ceramics were prepared by the conventional solid state reaction technique, and the effects of BNKT on the phase structure, microstructure, ferroelectric and piezoelectric properties of (1-x)KNN-xBNKT ceramics were investigated. The addition of BNKT strongly affects the microstructure of these ceramics, and changes the crystalline structure of these ceramics from an orthorhombic phase with x < 0.02 to a tetragonal phase with x≥ 0.03 at room temperature. A coexistence of orthorhombic and tetragonal phases was identified in the range of 0.02≤x≤ 0.03. 0.975KNN-0.025BNKT ceramics show the optimum piezoelectric properties of d_(33) ~170 pC/N and k_p~0.38.