Development of high-temperature stable dielectric material

Abstract

Temperature stability is one of the important parameters for the capacitor to work in various temperature ranges. BaTiO3-based materials are one of the popular choices as X7R, X8R, X9R, and X8T (class II) materials in capacitors due to the high value and temperature stability of their dielectric permittivity. Several studies have revealed that the property and performance of these materials can be tailored by doping different elements at A and B sites. In this work, Ba(1-x) Srx Zr 0.1Ti0.9O3 + 2 wt% MgO (x = 0,0.02,0.04) was synthesized via the solid-state reaction method. Liquid phase sintering was adopted to assist in the formation of dense microstructures. For this purpose, MgO was used as a sintering aid. We studied the structural, morphological, dielectric, and energy storage properties of these composites. The powder X-ray diffraction pattern confirmed the formation of cubic phase in Ba(1-x) Srx Zr0.1Ti0.9O3. FESEM micrograph of these compositions revealed that the sample had been properly sintered and possesses a dense microstructure. In dielectric measurement, the εr -T and tanδ -T curves have been plotted for different compositions at different frequencies. The result showed stable dielectric properties with the variation of temperature in all composites, which is characteristic of temperature-stable dielectric materials. For all the compositions, it has been found that there is a decrease in dielectric constant with the frequency, which is due to a decrease in polarisations of the atoms or molecules with the increase in frequency. The flatness of the dielectric curve confirms that the studied material is highly preferable for Class II dielectric-type capacitors. The broadening of the dielectric peak is observed for all the compositions because of the diffusive phase transition. The variation of capacitance or ∊r in terms of TCC is –33 to +22% for a wide range of temperatures from −55 °C to +150 °C.