Combustion synthesis of TiFe by utilizing magnesiothermic reduction

Highlights: • Melting of Mg triggered the combustion reaction of magnesiothermic reduction of TiO₂. • Highly pure TiFe could be produced under pressurized atmosphere. • This new combustion synthesis process could be used for mass production of TiFe. - Abstract: This paper describes a new method for producing TiFe hydrogen storage alloy through combustion synthesis by utilizing the magnesiothermic reduction reaction. The reaction mechanism and the effects of a gaseous atmosphere and pressure on the purity of TiFe products and their hydrogen storage properties were examined in this study. In the experiments, Fe, TiO₂, and Mg were used as raw materials and were mixed in a molar ratio of 1:1:4. The mixture was compacted and then heated in a normal or pressurized atmosphere of hydrogen and argon. Temperature changes with time were measured, and the obtained results indicated that the melting of magnesium triggered the reaction. X-ray diffraction analysis revealed that highly pure TiFe could be synthesized in a pressurized atmosphere, containing both hydrogen and argon. The products synthesized in such a pressurized atmosphere stored approximately 1.0 mass% hydrogen and indicated flat plateaus. The process proposed in this study showed the possibility of being a new attractive production method for TiFe hydrogen storage alloy