Non-stoichiometry in titanium dioxide (rutile)

[摘要] The present investigation, which forms part of a general programme of research into the effects of departures from the stoichiometric composition on the physical and mechanical properties of ceramic compounds, is concerned with the defect structure of non-stoichiometric rutile. The physical properties of rutile, with particular reference to the effects of departure from the stoichiometric composition, have been briefly reviewed. The development and design of an apparatus, incorporating a sensitive microbalance, capable of measuring departures from the stoichiometric composition in rutile at low pressures of oxygen and at temperatures up to a maximum of 1300\(^o\)C is described in detail. The defect structure of non-stoichiometric rutile has been shown to alter as departure from the ideal composition increases. It is concluded that at small departures from the stoichiometric composition free anion vacancies are present, whereas at large departures the vacancies cluster on planes of the {100}, {101} and {110} types, which subsequently collapse by displacement of ½<101> forming interstitial cations. The departures from stoichiometric composition which have been observed in high-purity rutile are very small - much smaller than those previously reported in the literature. Larger departures found to occur in impure rutile can be attributed directly to electronic effects associated with impurity atoms. Much further work of a systematic and long-term nature will have to be carried out before the role of impurity atoms on the defect structure of non-stoichiometric rutile is understood.

[发布机构] University:University of Birmingham;Department:Department of Physical Metallurgy

[关键词] Q Science;QD Chemistry