INVESTIGATION ON PURITY AND THERMAL STABILITY OF Ag2O RAW MATERIAL USED TO SYNTHESIS Ag2Nb4O11 CERAMICS USING THERMAL AND PHASE ANALYSIS METHOD

Abstract

This paper reports on the newly found ferroelectric material, Ag₂Nb₄O₁₁ ceramics synthesised using solid state reaction and characterised its properties using X-ray powder diffraction, ferroelectric test and impedance spectroscopy. However, the synthesis of phase-pure Ag₂Nb₄O₁₁ ceramics was unsuccessful due the presence of other phases such as AgNbO₃, Ag metal and un-reacted Nb₂O₅ raw material. The inhomogeneity of the sample was clearly seen in impedance measurement which showed electrical inhomogeneity of bulk and grain boundary capacitances. Difficulties in obtaining phase-pure Ag₂Nb₄O₁₁ ceramics has motivated an investigation on the purity and thermal stability of Ag₂O raw material. X-ray diffraction patterns showed that Ag₂Nb₄O₁₁ consist of Ag₂Nb₄O₁₁, AgNbO₃, Ag metal and un-reacted raw material. Studies on Ag₂O raw material was carried out by heating and weighing it after each different temperature. Weight loss observed at temperatures 120^oC, 270^oC and 400^oC correspond to the loss of water and the decomposition of Ag₂O to Ag metal. In this study, the Ag₂O used was mostly contained Ag metal than the Ag₂O. The instability nature of Ag₂O at high temperature may contribute to the difficulties in obtaining phase pure Ag₂Nb₄O₁₁ product.