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 120oC, 270oC and 400oC 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.