High Anticorrosive Properties of Hot-Dip 55 wt% Al-Zn-Si Coatings on Q235 Steel
A comparative study of the morphology and anticorrosive behaviour of commercial 55 wt% Al-Zn-Si coatings (CC) and hot-dip 55 wt% Al-Zn-Si coatings (HD) on Q235 steel was performed by using surface analysis techniques and electrochemical measurements. Despite the ingredients of the Al-rich dendritic phase for HD coating similar to the ingredients for CC coating, aluminum content in the Zn-rich phase for HD coating was almost twice higher than aluminum content for CC coating. The difference of surface morphologies and chemical compositions in Zn-rich phases for the two 55 wt% Al-Zn-Si coatings could significantly affect their corrosion properties. The corrosion behavior of the two coatings was investigated in 0.01 mol L-1 NaCl + 0.01 mol L-1 NaHSO3 aqueous solution. Both polarization curve and electrochemical impedance spectroscopy results indicate HD coatings had much higher corrosion resistance than CC ones.
Sihai Jiao, Zhengyi Jiang and Jinglong Bu
W. L. Yao et al., "High Anticorrosive Properties of Hot-Dip 55 wt% Al-Zn-Si Coatings on Q235 Steel", Advanced Materials Research, Vols. 146-147, pp. 306-309, 2011