Synthesis, formation and characterisation of MgNb2O6 powder in a columbite-like phase

A modified mixed oxide synthetic route has been developed for the synthesis of the columbite-like phase of magnesium niobate, MgNb2O6, (MN). Magnesium carbonate hydroxide pentahydrate was employed as a source of magnesium, with the formation of columbite phase investigated as a function of calcination temperature and dwell time by XRD and DTA. The particle size distribution of the calcined powder was determined by laser diffraction, with the morphology, phase composition and crystal structure determined via SLM, TEM and EDX techniques. If has been found that the Mg4Nb2O9 phase tends to form together with the columbite-type ;phase MgNb2O6, although a single columbite-like phase of MgNbzO6 was obtained for a calcination temperature of 1150 degrees C with a dwell-time of 4h. (C) 1999 Elsevier Science Limited. All rights reserved.