Electrochemical Behavior and Microstructure of Recyclable Aluminium-magmesium Alloy Hot-dip Coating Deposited on Low Carbon Steel Substrates

By Panomkorn KWAKHONG and Apichart ARTNASEAW and Chaiyaput KRUEHONG
Published in Journal of Iron and Steel Research, International NULL 2015

Abstract

With the abundance and good corrosion resistance of aluminium, hot-dip technique was used to prepare the recycled Al with 8.2 mass% Mg alloy coating on low carbon steel substrates. Electrochemical behavior of this coating was investigated by anodic polarization and open circuit potential measurement. Its microstructure and composition were observed by scanning electron microscope and energy-dispersive X-ray spectrometry, respectively. The long lasting corrosion performance of coated steels was investigated under the salt fog spray test. From anodic polarization curves and open circuit potential, recycled Al with 8.2 mass% Mg coating performed adequate sacrificial ability. At 0.40 V, current density of recycled Al with 8.2 mass% Mg alloy coating was about 200 000 times higher than that of pure recycled Al coating, and was about 0.5 times lower than that of Zn coating. The microstructure of recycled Al with 8.2 mass% Mg alloy coating on the steel substrate consisted of Al3Mg2, Al-Fe intermetallic compound and Al matrix. The results from salt fog spray test showed that recycled Al with 8.2 mass% Mg alloy coated steel had similar corrosion resistance ability to Zn coated steel.

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