Synthesis and Characterisation of AWO4 (A = Mg, Zn) Tungstate Ceramics

Abstract

The AWO4 (A = Mg, Zn) tungstate ceramics have been prepared using conventional solid-state route and characterised. Samples were analysed X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy (IS). Phase-pure ZnWO4 and MgWO4 were successfully obtained at temperatures 1000°C for 24 and 12 hours, respectively, where both compounds had a wolframite-like structure monoclinic, space group P2/c (13). Preliminary results of electrical properties of ZnWO4 indicated that ZnWO4 is a dielectric insulator with permittivity, ϵ r ∼ 20 at room temperature. The inhomogeneous electrical properties of ZnWO4 is observed where the grain boundary and bulk contributions effects were seen at temperature excess of 100°C.