Atomic diffusion in liquid Ni, NiP, PdNiP, and PdNiCuP alloys

We investigated the self-diffusion of Ni in liquid Ni, Ni80 P20, Pd40 Ni40 P20, and Pd43 Ni10 Cu27 P20 at temperatures up to 1795 K with incoherent, quasielastic neutron scattering. Values of measured self-diffusion coefficients vary over the accessible temperature ranges as a function of composition only within 10%. Although mixing has a drastic effect on the liquidus temperature and the undercooling capabilities, a relation between these properties and the atomic diffusion in the liquid is not observed. Apparently, diffusive motion is governed by the packing fraction of the atoms, that is very similar in these dense liquids. © 2004 American Institute of Physics.