Study of corrosion and microstructural behavior of hot dipped aluminized steel

Hot dipped aluminizing is often used to improve steel’s resistance to corrosion, oxidation and wear. The growth behavior in the intermetallic layer by introducing different dipping times and various of molten aluminum temperatures were investigated in detail. Microstructure and phase analysis were studied by optical microscopy and X-ray diffraction method, respectively. The results showed that the top portion of the coated steel substrate were composed of a thin layer of α- Al2O3, followed by a thicker layer of aluminum pure, Thinner layer of FeAl3 , and then a much thicker of Fe2Al5 . The intermetallic layer was ‘thick’ and exhibited a finger-like growth into the steel. The thickness of Al-Fe intermetallic layer on the steel base was increased with an increase in hot dipping temperature and time. Electrochemical properties of the hot dip aluminized samples were also investigated. The aluminized surface of carbon steel exhibited an improved resistance to corrosion.

Keywords:

aluminum hot dip coating , intermetallic layer , corrosion resistance