A novel method for preparation of barium strontium titanate nanopowders

Ba0.6Sr0.4TiO3 (BST) nanopowders have been prepared using the modified citrate method with ammonium nitrate as a combustion promoter, and the formation mechanism, phase evolution, and particle size have been investigated using TG/DTA, XRD, and SEM. It is found that the peaks of barium carbonate disappear when the precursor powders are calcined at 650 °C. The fine particles of the nanopowders calcined with the combustion promoter addition are homogeneous and well-dispersed and their narrow size distribution is about 60–90 nm. Comparatively, the particles of the powder calcined without the ammonium nitrate addition are inhomogeneous, with an evident agglomeration. The mechanism for the above results is attributed to that a reaction can generate soft and loose precursor powders by the adoption of ammonium nitrate, and hence a pure BST phase could occur at the low synthesis temperature of 650 °C.