Hydriding combustion synthesis of TiFe

Abstract Titanium iron (TiFe) is one of the most attractive metal hydrides because of abundant and low cost raw materials and moderate conditions for hydrogenation and dehydrogenation; however, it has not been practically used due to time-consuming and energy-consuming activation treatment. Aiming to improve the initial activity of TiFe, we applied hydriding combustion synthesis (HCS), which has attractive advantages for the direct production of metal hydride; time saving, energy saving, and highly pure product that is highly hydrogenated and does not require the activation treatments for metal hydride production, to the TiFe production. In the experiments, hydrogen storage reaction of titanium (Ti + H 2  = TiH 2  + 144 KJ) was utilized for HCS of TiFe because the adiabatic flame temperature of this reaction was estimated to be 2000 °C, which is enough high for melting both iron and titanium. The raw material of Ti and Fe powders mixed with 1:1 molar ratio was covered with additional Ti powders from above and placed in hydrogen atmosphere. After the Ti powders were ignited by electrically heated carbon filament, the TiFe synthesis reaction (Ti + Fe = TiFe + 40 kJ) occurred successfully. The HCSed TiFe was activated easily and stored hydrogen approximately 1.7 mass% indicating improved initial activity for hydrogen storage.