Enhanced reactive diffusion of Zn in a nanostructured Fe produced by means of surface mechanical attrition treatment

Nanostructured pure Fe was produced on a coarse-grained (CG) sample using surface mechanical attrition treatment (SMAT). The formation behaviors of Fe–Zn compound layer were studied in nanostructured Fe electroplated with a Zn layer. In comparison with the CG sample, the Fe–Zn reaction in the nanostructured Fe showed an onset temperature decrease of ∼21 °C and an increased enthalpy change of ∼70%. The activation energy for the growth of Fe–Zn compound layer decreased from ∼167.1 kJ mol−1 in the CG sample to ∼108.0 kJ mol−1 in the SMAT sample. The grain size of the formed FeZn13 phase in the Zn/SMAT-Fe sample was much smaller than that in the Zn/CG-Fe sample after the same diffusion treatment. The enhanced reactive diffusion behaviors in the SMAT sample are attributed to the existence of a large number of grain boundaries in the nanostructured Fe.