EFFECT OF Nb SUBSTITUTION ON THE PIEZOELECTRIC AND DIELECTRIC PROPERTIES OF 0.95(K_0.5Na_0.5) NbO₃-0.05Li (Sb_{1 − x}Nb_x)O₃ CERAMICS

ABSTRACT

In this study, lead-free 0.95(K_0.5Na_0.5)NbO₃-0.05Li(Sb_{1 − x} Nb _x )O₃ system ceramics were fabricated according to the amount of Nb substitution for Sb site of LiSbO₃ ceramics and their dielectric and piezoelectric characteristics were investigated. With increasing the amount of Nb substitution, electromechanical coupling factor (k_p), density and piezoelectric constant (d₃₃) increased up to 1mol% Nb and decreased above 1mol% Nb. With increasing the amount of Nb substitution, dielectric constant linearly decreased and Curie temperature increased. At the 1mol% Nb substitution composition ceramics sintered at 1040°C, electromechanical coupling factor (k_p), density, dielectric constant (ε_r), piezoelectric constant (d₃₃) and Curie temperature (Tc) showed the optimal value of 0.41, 4.35 g/cm³, 789, 206 pC/N and 395°C, respectively for piezoelectric device application.

Keywords:

• lead-free ceramics
• piezoelectric constant
• (Na,K)NbO₃
• electromechanical coupling factor
• dielectric constant