Abstract
Hydrogen-absorbing intermetallic compounds have to be activated prior to hydrogen absorp-tion. Recent topics relating to the alloy surfaces, which are involved in this activation, are disc-ribed here. LaNi5 exhibits strong oxygen induced surface segregation. The segregation occurs with each hydrogenation-dehydrogenation cycle, for-ming fresh active surface. TiFe is considered to be special in the sense that no significant segregation occurs at room temperature. For amorphous Pd30Zr70 and Cu70Zr30, hydrogen induces segregation.
