Diffusion along [001] tilt boundaries in the Au/Ag system—I. Experimental results

The parameter, δ b D b Ag, for the chemical diffusion of Ag along the tilt axes of a series of [001] symmetric tilt boundaries in the Au/Ag system, was measured as a function of temperature and tilt angle at relatively lowtemperatures. ( D b Ag = boundary diffusivity; δ D = boundary thickness) Sixteen boundaries were studied using a newly developed surface accumulation method. δ b D b Ag was found to vary quite smoothly with tilt angle (i.e. no sharp minima or cusps at low-Σ misorientationswere observed) in a manner consistent with the structural unit model. The activation energies were found to be smooth functions of the tilt angle and to lie in the range 0.70–0.85 eV. The pre-exponential factors in the Arrhenius expression for δ b D b were ∼3 orders of magnitude smaller than many of those reported in the literature for diffusion at higher temperatures.