Piezoelectric and dielectric properties of low temperature sintering (Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3 ceramics substituted with (Sr0.95Ca0.05)TiO3

Abstract

In this work, in order to develop lead-free piezoelectric ceramics with excellent dielectric and piezoelectric properties, (1−x)(Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3+x(Sr0.95Ca0.05)TiO3 ceramics were fabricated as a function of (Sr, Ca)TiO3 substitution using a conventional mixed oxide method. The microstructure, dielectric and piezoelectric properties were systematically investigated as a function of amount of the (Sr, Ca)TiO3 substitution. A morphotropic phase boundary(MPB) between orthorhombic and tetragonal ferroelectric phases has been identified in the composition range of 0.005<x<0.01. At the low sintering temperature of 1020°C, the optimum values of piezoelectric constant(d33)=310pC/N, planar piezoelectric coupling coefficient(kp)=0.44, mechanical quality factor (Qm)=98 and dielectric constant(εr)=1687, were obtained from the ceramics substituted with x=0.01, respectively.