Effects of B2O3 doping on the dielectric and piezoelectric properties of (K,Na,Li)NbO3–BaZrO3–(Bi,Na)TiO3 ceramics

Abstract

(K,Na,Li)NbO3–BaZrO3–(Bi,Na)TiO3–xB2O3 (KNLN–BZ–BNT–xB2O3) ceramics were prepared by the conventional solid-state reaction method. The effects of B2O3 content on dielectric and piezoelectric properties of KNLN–BZ–BNT ceramics were studied. Based on identification by X-ray diffraction, all samples showed a two-phase coexistence zone consisting of rhombohedral and tetragonal phases. It was found that B2O3 addition is effective both for obtaining a dense structure and for increasing the grain size of KNLN–BZ–BNT ceramics sintered at a low temperature. For ceramics with x = 0.5 wt%, the sintering temperature was observed to reduce from 1200 °C to 940 °C, while the samples maintained a high relative density around 97%. Because of the high densification and large grain size, the dielectric and piezoelectric properties improved. As a result, the ceramics with x = 0.5 wt% sintered at 940 °C exhibited good properties of d 33 = 197 pC N–1, k p = 0.29, tan δ = 0.029 and ε r = 1889, together with a Curie temperature (T c) of 222 °C.