Kinetics of hydrogen absorption by TiCr2 and Ti–Cr based alloys at low temperatures

This paper reports kinetic properties of H2 absorption of TiCr2 and a Ti–Cr based alloy: Ti0.44Zr0.56Cr0.86Fe0.68Ni0.21Mn0.25Cu0.03. In this study, the influence of surface oxidation of these alloys on the H2 absorption rate was investigated from a viewpoint of practical application to a metal hydride (MH) freezer system. The changes of reaction mechanisms of hydrogen absorption by various surface conditions were elucidated by measurements of the pressure and temperature dependences of the reaction rate of these alloys.

► Ti–Cr based alloy has much high durability against surface oxidation than the TiCr2.
► The rate controlling steps are changed by thickness of surface oxide layers.
► Our Ti–Cr alloy is suitable for practical use where surface oxidations may take place.