Preparation of LaxSr1−xMnO3 ultrafine powder by spray pyrolysis

The major factors affecting the particle size and morphology of LaxSr1-xMnO3 powder produced by spray pyrolysis are found to be the pyrolysis temperature, the rate of gas to liquid flow rates and concentration of the raw materials. The powders consist mainly of less than 1 mu m spherical particles. The smaller particles are the perfect spheres. Particles greater than 2 Irm are mostly fragments of spheres. The chemical composition of LaxSr1-xMnO3 powder accords approximately with that of feed. The powder produced by spray pyrolysis is amorphous, which could be transformed into single structure of hexagonal-rhombohedral perovskite after being calcined at 1200 degrees C for 2 h in air and form the larger hard agglomerates. (C) 1997 Elsevier Science S.A.