A study was made of the diffusion of Hf in amorphous Ni54Zr46 at pressures of up to 1GPa. The results of these measurements could be described by the expression:

D(m2/s) = 7.4 x 10-17exp[-0.76(eV)/kT]

The associated activation volume was 0.0085nm3. The activation volume and activation energy were found to be related by Keyes’ rule, with a coefficient of 4.6. It was concluded that, in NiZr glasses, the activation volume for self-diffusion was positive and was of the order of, but less than, the relevant atomic volumes. It was shown that the relatively small activation volumes and energies which were measured here were not incompatible with a vacancy mechanism if an extrinsic diffusion regime due to Fe impurities, as in -Zr, also operated in this glass.

A.Grandjean, P.Blanchard, Y.Limoge: Physical Review Letters, 1997, 78[4], 697-7000