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    Item type:Publication,
    Synthesis, phase formation and characterization of Co4Nb 2O9 powders synthesized by solid-state reaction
    (2008-12-01)
    Chaiyo, N.
    ;
    ;
    Ruangphanit, A.
    ;
    Vittayakorn, W. C.
    ;
    A corundum-type structure of cobalt niobate (Co<inf>4</inf>Nb <sup>2</sup>O<inf>9</inf>) has been synthesized by a solid-state reaction. The formation of the Co<inf>4</inf>Nb<inf>2</inf>O<inf>9</inf> phase in the calcined powders was investigated as a function of calcination conditions by differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Morphology and particle size have been determined by scanning electron microscopy (SEM). It was found that the minor phases of unreacted Co <inf>3</inf>O<inf>4</inf> tend to form together with the columbite CoNb <inf>2</inf>O<inf>6</inf> phase at a low calcination temperature and short dwell time. It seems that the single-phase of Co<inf>4</inf>Nb<inf>2</inf>O <inf>9</inf> in a corundum phase can be obtained successfully at the calcination conditions of 900°C for 60 min, with heating/cooling rates of 20°C /min. © 2008 Trans Tech Publications, Switzerland.