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.
 Kopyciński, D. & Guzik, E. (2006). Growth of protective coating in the galvanizing of ductile iron castings. Archives of Foundry Engineering. vol. 6, 401-408.
 Kopyciński, D. & Szczęsny, A. (2013). Designation of coating thickness depending on the type of metal matrix of ductile cast iron during hot dip galvanizing of casting.Technologist. vol. 2, 40-43.
 Kopyciński, D. & Szczęsny, A. (2012). The effect of ductile cast iron matrix on zinc coating during hot dip galvanizing of castings, Archives of Foundry Engineering. vol. 12,iss. 4, 101-104.
 Kopyciński, D., Guzik, E. & Woźnica, H. (2006). The gradient structure zinc coating shaping at the surface of ductile cast iron. Archives of Foundry. vol. 6, 278-285.
 Kopyciński, D. (2010). The shaping of zinc coating on surface steels and ductile iron casting. Archives of Foundry Engineering. vol. 10 spec iss 1, 463-470.
 Kopyciński, D. & Guzik, E. (2007). The kinetics of zinc coating growth on hyper-sandelin steels and ductile cast iron.Archives of Foundry Engineering. vol. 7 iss. 4, 105-110.
 Marder A.R. (2000). The metallurgy of zinc-coated steel.Progress in Materials Science. vol. 45, 191-271.
 Tatarek, A., Liberski, P., Kania, H. & Podolski, P. (2008).The mechanism of formation hot dip galvanizing on iron alloys containing silicon. Materials Engineering, vol 6, 788-791.
 Kania, H. & Liberski, P. (2008). The structure and growth kinetics obtained dip zinc coating baths containing tin.Inżynieria Materiałowa. 3, 375-380. (in Polish)
 Liberski, P., Kania H., Podolski, P., Tatarek, A. & Kwiatkowski, L. (2008). Actual technological problems of batch hot-dip galvanizing process. Phisico Chemical Mechanics of Materials. 7, 301-307.
 Liberski, P., Tatarek, A., Podolski, P. & Kania H., (2007).Kinetics of the initial stage of formation dip zinc coatings on iron alloys with different silicon content. Ochrona przed korozją. 4, 173-178. (in Polish)
 Brody, H.D. & Flemings, M. (1966). Solute redistribution in dendritic solution. Transaction of the Metallurgical Society of AIME. 236, 615-624.
 Wołczyński, W., Guzik, E., Janczak-Rusch, J. & Kopyciński D. (2006). Morphological characteristics of multilayer/ substrate systems. Materials Characterizations. 56, 274-280.