Formation of TiO2 particles during thermal decomposition of Ti(NO3)4, TiOF2 and TiOSO4

Abstract In the paper, impact of the precursor decomposition conditions on the morphological and structural characteristics of TiO2 particles was discussed. The novelty and significance of the researches lay in the ability to control morphological features of the synthesized powder particles so that enhanced properties of the sintered ceramics can be obtained. The research program covered thermal decomposition of titanium nitrate, titanium oxyfluoride and titanium oxysulphate at different temperatures, with and without organic additive. Obtained titanium dioxide powder underwent analysis, namely, its phase composition, particle shape and dimensions were measured using X-ray and IR-spectra, as well as scanning electron microscopy. Activity of the obtained particles during sintering process was analyzed using dilatometer and microhardness measurement after sintering. It was found that spherical TiO2 nanoparticles of anatase and rutile phases can be obtained from decomposition of titanium nitrate at 700 °C. Thermal decomposition of other precursors, titanium oxyfluoride and oxysulfate, synthesized only anatase phase with particles of 200 and even 300 nm. Obtained spherical particles were smaller when temperature of decomposition was lower or the activator OP9 was added. However, lower decomposition temperature and additive had negative effect on sintering activity of the obtained particles, decreasing the microhardness of sintered specimens.