Chapters authored
Structural Aspects of Anatase to Rutile Phase Transition in Titanium Dioxide Powders Elucidated by the Rietveld Method
Titanium dioxide has attracted much attention since a long time ago due to its versatility as advanced material. However, its performance as semiconductor devices is very much dependent on the predominant crystalline phase and defect concentrations, which can be adjusted through the synthesis methods, thermal treatments and doping processes. In this work, an accurate structural characterization of titanium dioxide was used by X‐ray diffractometry supported by rietveld refinement and thermal analysis. The insertion of 5 mol% of zirconium silicate was able to stabilize anatase up to 900°C, permitting the oxygen vacancies to be significantly eliminated. It was demonstrated also that the changes in the isotropic thermal parameters for oxygen are related to reconstructive transformation necessary to promote the anatase‐to‐rutile phase transition. Independently of doping process, the crystallization process of anatase phase as a function of temperature increasing occurs exclusively due the reduction of lattice microstrain up to 600°C. However, above 650°C, that crystallization process becomes dependent of the increasing in crystallite size. The anatase crystallite growth event was only possible when the titanium dioxide was doped with zirconium silicate. Otherwise, the rutile phase amount starts to rise continually. Thus, there are optimistic expectations for that new composition to be a new semiconductor matrix for additional doping processes.
Part of the book: Titanium Dioxide