Chemical synthesis of unique intermetallic TiFe nanostructures originating from the morphology of oxide precursors

Abstract

In this study, intermetallic TiFe nanostructures were chemically prepared from Ti–Fe oxide precursors using a CaH₂ reducing agent in molten LiCl at as low as 600 °C. The used precursor was spherical oxide nanoparticles or commercial FeTiO₃ bulk powder. After the reduction treatment, the former precursor was changed to an aggregation of TiFe nanoparticles with a particle size of 44–46 nm. Surprisingly, the latter precursor was reduced to a layered morphology composed of TiFe nanoparticles with a particle size of 47–65 nm. An intermetallic compound with a unique layered morphology was found for the first time, and the layered morphology could have originated from the morphology of the FeTiO₃ precursor in which the Fe²⁺ and Ti⁴⁺ ions occupied alternating layers perpendicular to the trigonal c-axis. The precursor originated morphology was enabled by the proposed low reduction temperature method, and the environment-friendliness of the proposed method was finally evaluated using life-cycle assessment (LCA).