Effect of ball milling on hydrogen absorption properties of FeTi, Mg2Ni and LaNi5

The hydrogen absorption alloy powders, i.e. FeTi, Mg2Ni and LaNi5, were ball milled in an argon atmosphere for different periods and subsequently were hydrogenated with or without the exposure to the air. The size and morphology of the ball milled samples were examined by scanning electron microscopy (SEM). The present work demonstrates that ball milling of these alloy powders, which leads to the reduction in the particle size and to the creation of new clean surfaces, is effective for the improvement of the initial hydrogen absorption rate.