Iron-aluminium alloys, diffusion coatings

Sprayed, vacuum-deposited and plated coatings can be applied to most metals and to many non-metals, e.g. vacuum deposition is applied to many substrates including plastics spray application can be used for coating fabric, plastic and paper. Hot dipping and other diffusion processes are dependent on the nature of the substrate for the properties of the coating. Most commercial applications of aluminium coatings are on iron and steel with smaller quantities applied to aluminium alloys and plastics. 

Little, M. V., Bonding Aluminium To Ferrous Alloys , Machinery, N. Y., 56, 173 (1950) Drewett, R., Diffusion Coatings for the Protection of Iron and Steel , Part I, Anti-Corrosion, 16 No. 4, 11-16, April (1969)... 

Hot Dipped Coatings Major attempts have been made to improve the quality of aluminised steel strip. Requirements on coating thickness and uniformity have been imposed. It is the speed of sheet movement, length of path in the molten bath, temperature and composition of the bath that control the thickness of the intermetallic layer which lies below the aluminium outer surface. The process of intermetallic alloy formation is diffusion controlled, and it is usual that some dissolution of iron into the molten aluminium does occur at a rate, Ac/At, which is given by... 

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