A calcination technology for ultrafine La ₃NbO ₇ powder prepared by Sol-Gel process

In order to prepare ultrafine La ₃NbO ₇ powder, a potential material for thermal barrier coatings, the calcination process of La ₃NbO ₇ was studied in this paper. The precursor of La ₃NbO ₇ was synthesized by using a citric acid complex method. A calcination process had been systematically investigated. The reaction temperature was determined by differential scanning calorimetry(DSC). The phase composition of powders was characterized by X-ray diffraction(XRD), and the morphology was obtained by scanning electron microscope (SEM). The results revealed that the single-phase La ₃NbO ₇ powder could be successfully prepared while the calcination temperature exceeded 800°C and a better morphology could be maintained at 800°C for 4 hours. Considering all above, an optimum calcination scheme was adopted at 800°C for 4 hours. The as-prepared La ₃NbO ₇ powders had a grain size of about 50nm and an average particle size of about 300nm.