“…ICISS has also provided evidence that diffusion in the Fe/Cu(100) system occurs only in a very small fraction of the area of the surface [106]. Although the diffusion coefficient of Sn in Pt is not known, considering the bulk diffusion coefficient of other metals in platinum Sn diffusion into the Pt substrate should be negligible in a such temperature range [37], so that the mechanism of alloying appears to be dominated here, too, by surface diffusion of Pt atoms through defects of the Sn film. However, the mechanisms of diffusion in these systems, as well as in the Pt-Sn one is something that still needs to be studied in detail.…”