Bi0.5Na0.5TiO3 (BNT) powders with nanometre and micrometre sizes were prepared by an ultrasonic spray pyrolysis process. The BNT powders obtained from the spray solution without citric acid had a spherical shape and micrometre size. On the other hand, the BNT powders obtained from a spray solution with 0.4 M citric acid of had nanometre size at a calcination temperature of 700 degrees C. Single phase BNT powders with a rhombohedral structure were obtained at a calcination temperature of 700 degrees C. The sintering of pellets obtained from the micrometre sized BNT powders started at a temperature of 900 degrees C. On the other hand, sintering and grain growth of the pellet obtained from the nanometre sized BNT powders occurred even at the low temperature of 850 degrees C. The relative densities of the pellets obtained from the nanometre sized BNT powders were 95 and 96% of the theoretical density of BNT at sintering temperatures of 950 and 1000 C. The mean grain sizes of the pellets sintered at temperatures of 950 and 1000 degrees C were the same at 1.10 mu m.

Keywords: spray pyrolysis; nano powder