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This paper describes the self-ignition combustion synthesis (SICS) of highly active titanium iron (TiFe) in a high-pressure hydrogen atmosphere without employing an activation process. In the experiments, well-mixed powders of Ti and Fe in the molar ratio of 1:1 are uniformly heated up to 1085°C, the eutectic temperature of Ti-Fe binary system, in a pressurized hydrogen atmosphere at 1.0 MPa. The electric source is disconnected immediately after the ignition between Ti and Fe, and the mixture is cooled naturally. In the experiments, the exothermic reaction Ti + Fe  TiFe + 40 kJ occurs at 1085 °C after the hydrogenation and decomposition of Ti. X-ray diffraction analysis shows that the final product has only one phase-TiFeH 0.06 -which contains 1.55 mass% of hydrogen at 4.0 MPa of hydrogen pressure. The product obtained by SICS contains considerably more hydrogen quickly as compared to the commercially Manuscript for JALCOM 3 available product; this fact can be explained by the porous structure of the obtained product, which is observed using a scanning electron microscope. In conclusion, the SICS of TiFe saves time and energy, yields products with high porosity and small crystals, enables easy hydrogenation, and does not require activation processes.

(147 words)The paper describes the self-ignition combustion synthesis (SICS) of the hydrogen storage alloy TiFe 1-X Mn X (X = 0, 0.1, 0.2, 0.3, and 0.5) in a hydrogen atmosphere, where the hydrogenation properties of the products are mainly examined. In the experiments, the well-mixed powders of Ti, Fe, and Mn in the molar ratio of 1:1-X:X were uniformly heated up to 1473 K, and then were cooled naturally in pressurized hydrogen at 0.9 MPa. All products were successfully synthesized by utilizing the exothermic reaction, which occurred at around 1358 K. The XRD analysis showed that SICS generated TiFe 1-X Mn X in the range of X value from 0 to 0.3. All SICSed products absorbed hydrogen smoothly at 298 K at an initial pressure of 4.1 MPa. Most significantly, TiFe 0.8 Mn 0.2 improved the dual plateau property. The results revealed that SICS was quite effective for producing the hydrogen storage alloy TiFe 1-X Mn X .Self-ignition Combustion Synthesis of TiFe 1-X Mn X Hydrogen Storage Alloy 3

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