Diffusion in a temperature gradient - A single cycle method to determine frequency factor and activation energy of solid diffusion coefficients in alloys

An experimental procedure for determining the temperature dependence of diffusion coefficients in a single diffusion heat treatment is introduced. Diffusion in a temperature gradient in samples with initially symmetric “roof-shaped” concentration profiles of a suitable length scale and concentration range yields asymmetric profiles that allow the determination of the frequency factor D0 and the activation energy QD. The binary system Al-Cu is used as an example. The procedure is applicable to alloy systems with finite solute solubility.