1.Non-Additivity Effect

The average Ni-Ni and Nb-Nb distances of amorphous Ni_62.5Nb_37.5 are very close to their Goldschmidt diameters  in the elementary crystalline solids; while the Ni-Nb distance of 2.59 A°in the amorphous structure is shorter than the mean value (2.77 A°) of r_Ni-Ni and r_Nb-Nb, revealing a non-additivity effect.Such substantial contraction in the Ni-Nb distance by about 7% suggests strong bonding between Ni and Nb atoms in the amorphous alloy.