Badania porównawcze składu powierzchni w polikrystalicznych i monokrystalicznych stopach LaNi4,2Al0,8.

The surface chemical compositions of nanocrystalline LaNi4.2Al0.8 alloys was studied by Auger electron spectroscopy and compared to that of a polycrystalline sample. Results showed that the surface segregation of La atoms in the mechanically alloyed nanocrystalline LaNi4.2Al0.8 alloy is stronger compared to that of polycrystalline powders from arc-melted ingots. On the other hand, the level of oxygen impurities trapped in the mechanically alloyed powder during the processing is practically the same as in the arc-melted ingots. Small amounts of Fe impurities, which strongly segregate to the surface, could be responsible for the observed a little lower hydrogen storage capacity of the MA nanocrystalline LaNi4.2Al0.8 alloy compared to that of polycrystalline samples.