We have studied the influence of the substitution of Al for Ni in the ternary systems RENi5-xBx (RE=Gd, Y). The compounds synthesized in the pseudo-ternary systems RENi4-xAlBx (RE=Gd, Y) were studied in terms of their crystal structure, chemical composition and hydrogen sorption properties. Most of the compounds obtained in these systems crystallize with the CeCo4B-type structure RENi3AlB, with Al atoms replacing Ni. The partial replacement of Ni by Al observed leads to a decrease of lattice parameters compared to ternary RENi4B compounds. The new pseudo-binary phase GdB3 was also observed in this study for the first time.  Finally, it is reported that the compounds do not show any affinity towards hydrogen, with no absorption observed.





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