Experiments were carried out using couples between pure Zr and dilute binary alloys which contained Cu. The impurity diffusion coefficients were determined by using Darken’s relationship. That is, the interdiffusion coefficient at infinite dilution could be regarded as being the impurity diffusion coefficient of the solute. This method avoided problems, such as the surface chemical reaction of Zr specimens, which occurred during radio-tracer diffusion experiments. A linear Arrhenius relationship was obtained:

-Zr:     D (m2/s) = 1.0 x 10-5exp[-155(kJ/mol)/RT]

Y.Iijima, O.Taguchi: Journal of Materials Science Letters, 1995, 14[7], 486-9