Effect of calcination conditions on phase formation and particle size of nickel niobate powders synthesized by solid-state reaction

摘要

The solid-state mixed oxide method via a rapid vibro-milling technique is explored in the preparation of single-phase nickel niobate (NiNb_2O_6) powders. The formation of the NiNb_2O_5 phase in the calcined powders has been investigated as a function of calcination conditions by TG-DTA and XRD techniques. Morphology, particle size and chemical composition have been determined via a combination of SEM and EDX techniques. It has been found that the minor phases of unreacted NiO and Nb_2O_5 precursors and the Ni_4Nb_2O_9 phase tend to form together with the columbite NiNb_2O_6 phase, depending on calcination conditions. More importantly, it is seen that optimization of calcination conditions can lead to a single-phase NiNb_2O_6 in an orthorhombic phase.