Selected area electron diffraction SAED patterns were

The most commonly used method for the preparation of lanthanide hafnate ceramic is via solid-state reaction of metal oxides [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17] and [18], including mixed-oxide route via reactive spark plasma sintering [19] or vacuum sintering [20] and [21]. By employing the traditional mixed oxide processing route, solid state reaction [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20] and [21] leads to the formation of crystalline Ln2Hf2O7 after extended calcination time at high temperature owing to the low specific surface area of the metal oxides at which Staurosporine reaction occurs. In addition, pleura process of grinding/ball-milling in organic solvent (to preserve the stoichiometry of the components), pelleting and sintering is often required to be repeated to allow sufficient interdiffusion of cations for the preparation of single phase samples. As a result, a few wet chemistry routes have been developed for the preparation of Ln2Hf2O7 materials. All wet chemistry methods involve mixing of reactant precursors at the molecular level, thus better chemical reactivity. These soft chemical methods for the preparation of Ln2Hf2O7 include coprecipitation [22], the Pechini polymeric route [23], molten salt [24] and combustion processing [25], [26], [27] and [28].