High relative permittivity, low dielectric loss and good thermal stability of novel (K0.5Na0.5)NbO3–Bi(Zn0.75W0.25)O3 solid solution

Abstract

(1−x)(K0.5Na0.5)NbO3–xBi(Zn0.75W0.25)O3 [(1−x)KNN–xBZW, 0≤x≤0.015] ceramics were prepared by a conventional solid state reaction method. The effects of BZW addition on the phase transition, microstructure and dielectric performances of KNN ceramics were systematically investigated. The temperature dependences of the relative permittivity illustrate that the small amount of BZW addition can effectively improve the temperature stability and relative permittivity of ceramics below the Curie temperature. As x=0.01, the ceramic showed superior dielectric temperature stability (±15%) and a relatively high permittivity (~1300) over the temperature range from 150 to 350°C. In particular, the dielectric loss was prominently reduced below 5% from room temperature to ~470°C, which suggests that this ceramic is a promising candidate for high-temperature capacitor application.