Preparation of spherical TiO2/SnO2 powders by ultrasonic spray pyrolysis and its spinodal decomposition

Spherical TiO₂/SnO₂ powders were prepared from the TiCl₄-SnCl₄ aqueous solution by ultrasonic spray pyrolysis. The particle size, particle-size distribution and morphology of the powders were studied in relation to concentration of source solutions and reaction temperatures. The width of the compositional undulation induced by spinodal decomposition in the sintered bodies increased with increasing starting particle sizes, which resulted from micro-compositional heterogeneity in the form of a solid solution within a TiO₂/SnO₂ secondary sphere.