Hydrogen-Induced Enhancement of Interdiffusion in Cu-Ni Diffusion Couples

Drastic enhancements of the interdiffusion were observed in Cu-Ni diffusion couples when samples were heated under high hydrogen pressures (~5GPa). Interdiffusion coefficients measured between 600--800^∘C were increased by ~10⁴ times on the Ni-rich end and by ~10 times on the Cu-rich end. The observation is explained in terms of superabundant vacancy formation in the presence of interstitial hydrogen atoms.