Influence of TiSn ratio and synthesis method in iron niobate doped with Sn and Ti. [Fe0.4Ti0.2 − xSnxNb0.4O2 solid solutions]

In this study, Fe0.4Ti0.2 − xSnxNb0.4O2 solid solutions have been synthesized from both ceramic and gel colloidal methods from Fe2O3, Nb2O5, TiO2, SnCl2.2H2O and FeCl3, NbCl5, TiCl4, SnCl2.2H2O respectively. Two kinds of solid solutions with orthorhombic and tetragonal FeNbO4 structures have been obtained. The results indicate that solid solutions structure depends on firing temperature, composition, i.e. TiSn ratio and synthesis method. The optimal composition range to obtain solid solutions with low temperature structures (monoclinic and orthorhombic) is 0.10 ≤ x ≤ 0.15, but only in samples prepared by colloidal gel method, a single phase with these structures is obtained (900–1100 °C). Solid solutions with tetragonal structure are stable at high temperature and a single phase with this structure is obtained at 1300 °C in samples with x < 0.10.