Decomposition of (Ti2xFe1−xSb1−x)O4 solid solutions below 1673 K

The pseudo-binary TiO2–FeSbO4 system was investigated by means of thermogravimetric analysis below 1673 K in O2. Rutile-type solid solutions were synthesised at 1373 K in O2 by means of a solid state reaction between the two pure end members TiO2 (rutile) and FeSbO4 mixed in stoichiometric amounts. Thermal stability of the (Ti2xFe1−xSb1−x)O4 solid solution increases with rutile content; equimolar (Ti1.00Fe0.50Sb0.50)O4 solid solutions decompose at about 1673 K forming a TiO2-enriched solid solution and FeSbO4, that subsequently decomposes into Fe2O3 (hematite) and a volatile Sb oxide, probably Sb4O6. For compositions characterised by higher Ti content the decomposition temperature is higher than 1673 K.