Fast synthesis of TiNi by mechanical alloying and its hydrogenation properties

International audienceMechanical alloying is widely used for the synthesis of hydrogen storage materials. However, amorphization and contamination triggered by long-time milling are serious drawbacks for obtaining efficient hydrogen storage. In this work, short-time ball milling synthesis is explored for a representative hydride forming compound: TiNi. Through structural, morphological and chemical characterizations, we evidence that formation of TiNi is complete in only 20 min with minor Fe contamination (0.2 wt%). Cross-sectional analysis of powder stuck on milling balls reveals that alloy formation occurs through the interdiffusion between thin layers of co-laminated pure elements. Hydrogenation thermodynamics and kinetics of short-time mechanically alloyed TiNi are similar to those of coarse-grained compounds obtained by classical high-temperature melting. Mechanical alloying is a suitable method for fast and energy-efficient synthesis of intermetallic compounds such as TiNi