Thermal behaviour of titania based materials -: Mathematical modeling of emanation thermal analysis results

Emanation thermal analysis (ETA) was used in the characterization of microstructure changes during heating of precursors for the titania based materials: hydrous titania, TiO2.nH(2)O (n=0.58) and hydrous titania containing 10% ruthenia, (TiO2)(0.9)(RuO2)(0.1).nH(2)O (n=1.5). The precursors were heated at the constant rate 6 K min(-1) in argon flow in the range 20-1000degreesC. ETA results were compared with the theoretical curves simulating the temperature dependences of radon release rate, E(T). Two mathematical models were used in the simulation. The models considered either subsequent or simultaneous solid state processes (i.e. dehydration, crystallization or phase transition, resp.) during thermal treatment of titania based materials. A good agreement was found between experimental and the simulated ETA curves. The results of ETA were confirmed by XRD patterns of intermediate products of thermal treatment of the precursors.