Dielectric and Piezoelectric Properties of (Na,K)(Nb,Sb)O₃ Ceramics Substituted with (Na,Li,Bi)TiO₃

Abstract

Lead-free (1-x)(K_0.5Na_0.5)_0.97(Nb_0.96Sb_0.04)O₃+x(Na_0.25Li_0.25Bi_0.5)TiO₃ ceramics were synthesized using conventional solid state sintering method and then the effect of (Na_0.25Li_0.25Bi_0.5)TiO₃ (abbreviated as NLBT) substitution on the microstructure and piezoelectric properties were investigated. The specimens exhibited a pure perovskite structure. The grain size of the specimens decreased with increasing the content of NLBT substitution. The phase transition temperature of orthorhombic-tetragonal (T_O-T) and tetragonal-cubic (T_C) were decreased with increasing the content of NLBT substitution. 0.5 mol% NLBT substituted (K_0.5Na_0.5)_0.97(Nb_0.96Sb_0.04)O₃ ceramics exhibited the optimum values of d₃₃ = 171pC/N, k_p = 0.467 and Q_m = 320. The results show that 0.995NKN-0.005NLBT composition is a promising candidate material for piezoelectric device applications.

Keywords:

• Lead-free ceramics
• piezoelectric constant
• electromechanical coupling factor
• (K_0.5Na_0.5 ) (Nb_0.96Sb_0.04)O₃
• NLBT

Funding

This work was supported by 2014 Semyung University Fund.