A kinetic and mechanistic study of thermal decomposition of strontium titanyl oxalate

Thermal decomposition of anhydrous strontium titanyl oxalate proceeds through a series of complex reactions to form strontium metatitanate at high temperature. Among them the decomposition of oxalate is the first major thermal event. A kinetic study of oxalate decomposition in the temperature range 553-593 K has been carried out by cooled gas pressure measurement in vacuum. Results fitted the Zhuravlev equation for almost the entire alpha-range (0.05-0.92) indicating the occurrence of a diffusion-controlled, three-dimensional rate process. The activation energy has been calculated to be 164 +/- 10 kJ mol(-1). Results from elemental analysis, TGA, IR and SEM studies of undecomposed and partially decomposed samples have been used to supplement kinetic observations in formulating the mechanism for oxalate decomposition. (C) 2005 Elsevier B.V. All rights reserved.