Interdiffusion in molten Pd-Cu-Ni-P alloys, above the melting point, and impurity diffusion in Pd40Cu30Ni10P20, above and below the glass transition, were investigated. For interdiffusion measurements in liquid alloys, capillary methods were used at 973 to 1373K. Up-hill diffusion was observed for Pd and P in the presence of chemical gradients of Cu and Ni, respectively. This correlated with mixing enthalpies that had been calculated for the partial ternary systems. The measured temperature dependence of the interdiffusion coefficient was in accord with the predictions of mode-coupling theory. The temperature dependence of the impurity diffusion coefficients in the non-relaxed glass exhibited a non-linear Arrhenius behavior, with a kink near to the glass transition. After long-term relaxation at temperatures well below the glass transition, the coefficients obeyed a uniform Arrhenius dependence over the entire temperature range; with reduced diffusion coefficients below the glass transition.

Diffusion in PdCuNiP Alloys from the Amorphous to the Liquid State. A.Griesche, T.Zumkley, M.P.Macht, S.Suzuki, G.Frohberg: Materials Science and Engineering A, 2004, 375-377, 285-7