A STUDY OF THE INTERACTION BETWEEN IRON(III)OXIDE AND TITANIUM(IV)OXIDE AT ELEVATED-TEMPERATURES

The bulk interaction between iron(III) oxide and titanium(IV) oxide occurs at temperatures in excess of 773 K. Initially iron(III) ions dissolve in the titanium(IV) oxide structure to produce a substitutional solid solution. Magnetic evidence suggests that there is a solubility limit of iron(III) ions in the region of ca. 3 atom %. Significantly the phase transition from the anatase phase to the rutile phase is observed to occur approximately 200 K lower in the presence of iron than when it is absent. Further reaction between iron(III) oxide and the saturated solution in the rutile phase occurs at 1073 K with the formation of pseudo-brookite. Under high vacuum conditions the thermal decomposition of iron(III) oxide to magnetite (Fe3O4) is suppressed by contact with titanium(IV) oxide, but the oxygen which would have been released during this phase transition is released at a later stage, when it is likely that ilmenite is formed.