Characterization and sinterability of nanophase titania particles processed in flame reactors

Flame aerosol reactors are a route for large scale processing of nanostructured materials. However, fundamentals about processing-structure-property relationships have not been extensively researched. This work utilized three different burners to obtain a wide range of flame processing conditions (different time-temperature histories) to study the formation of nanophase titania particles. At low precursor reaction temperatures of about 400 degrees C, amorphous titania was obtained. At intermediate temperatures of 900 similar to 1430 degrees C, mixtures of anatase and rutile phase titania were obtained. At high temperatures of 1500 similar to 1570 degrees C, spherical particles of 100% anatase titania were obtained. A qualitative explanation of the different phase formation has been provided. Transmission Electron Microscopy was used to study particle morphology, size and agglomeration. Sizes of the titania particles produced by the designed burners varied from 10 to 100 nm, depending on processing conditions. In situ light scattering measurements were made to examine the evolution of the particle sizes. Post-sintering experiments were carried out to illustrate superior sinterability of the nanophase titania powders.