Zn-Al-Mg 용융합금도금강판의 소지철 두께에 따른 Cut-edge 부식특성 및 부식거동 해석

Abstract

Hot-dip zinc-coated steel sheets have been widely used in various industrial markets from construction to automotive parts due to their excellent corrosion resistance. Recently, it has been reported that the addition of Mg and Al to the zinc coating provides rich opportunities for enhancing the corrosion resistance of the coatings. The corrosion behavior of Zn-Mg-Al coatings is strongly related to the complex microstructures of the coating layer and the electrochemical activity of each intermetallic structure, which reacts differently with various electrolytic elements in the corrosive environment. However, the metallographic microstructure of the Zn-Mg-Al coating layer changes depending on the alloy composition of Mg and Al, and its effect on corrosion resistance has not yet been clarified. To establish optimum manufacturing conditions and alloy compositions for the most favorable Zn-Mg-Al alloy coatings, experimental demonstration of the effect of each metallographic phase and structure on corrosion performance is greatly needed. In this work, we report on the effect of steel thickness for the corrosion characteristics of alloy coated steel. In addition, the corrosion mechanism will be discussed in terms of the microstructural and electrochemical properties of the Zn-Mg-Al alloy coated steel sheets.