Application of grazing incidence wide-angle X-ray scattering to characterise mechanically plated coatings

Post-mechanical plating heat treatment on zinc and zinc–tin coatings resulted in the formation of an iron–zinc-rich intermetallic layer between the substrate and the coatings, while the outer coating layer became tin-rich in the case of heat-treated zinc–tin coatings. The novel use of grazing incidence wide-angle X-ray scattering detected not only ζ-FeZn 13 , δ 1p -Fe 13 Zn 126 and δ 1k -FeZn 6.67 phases but also Γ 1 -Fe 11 Zn 40 and Γ-Fe 4 Zn 9 phases due to the higher resolution and signal-to-noise ratio of synchrotron X-ray diffraction (XRD) compared to traditional XRD. Microstructure evolution models during the heat treatment of mechanically plated zinc and zinc–tin coatings are proposed. The formation of iron–zinc intermetallic phases was in the sequence of ζ-FeZn 13 , δ 1p -FeZn 10 , δ 1k -FeZn 7 , Γ-Fe 3 Zn 10 and Γ 1 -Fe 5 Zn 21 phases when the heat treatment duration increased.