Diffusion of Copper in Iron

Abstract

Using ⁶⁴copper and the residual‐activity technique, diffusion of copper in iron has been studied in both the paramagnetic and the ferromagnetic phases. The diffusivities (cm²/sec) can be described as follows: D_Cu/Fe=0.57 exp(−57 000/RT) (800°–1050°C, paramagnetic phase), D_Cu/Fe=0.47 exp(−58 380/RT) (650°–750°C ferromagnetic phase). The decrease in the diffusivity at the Curie temperature has been discussed in light of the theories of spin‐ordering and the temperature dependence of the elastic constants. The results do not show a change in activation energy at the transition temperature.