The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip
galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term
protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion
of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the
Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic
specimens were prepared, intermetallic layers were measured and diffusion coefficient (D) were calculated. It was found that the diffusion
coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained
on ductile cast iron EN-GJS-500-7.