Effect of Heat Treatment on Corrosion Resistance of Zn-Mg-Al Alloy Coated Steel
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Hot-dip Zn-Mg-Al coatings have a complex microstructure consisting of Zn, Al, and MgZn 2 phases. Its crystal structure depends on alloy content and cooling rates. Microstructure and corrosion resistance of these coatings might be affected by heat treatment. To investigate effect of heat treatment on microstructure and corrosion resistance of Zn-Mg-Al coatings, Zn-1.5%Mg-1.5%Al coated steel was heated up to 550 oC at a heating rate of 80 oC/s and cooled down to room temperature. At above 500 oC, the ternary phase of Zn-MgZn 2 -Al was melted down. Only Zn and MgZn 2 phases remained in the coating. Heat- and non-heat-treated specimens showed similar corrosion resistance in Salt Spray Test (SST). When a Zn-3.0%Mg-2.5%Al coated steel was subjected to heat treatment at 100 oC or 300 oC for 200 h and compared with GA and GI coated steels, the microstructure of coatings was not significantly changed at 100 oC. However, at 300oC, most Al in the coating reacted with Fe in the substrate, forming a Fe-Al compound layer in the lower part of the coating. MgZn2 was preferentially formed in the upper part of the coating. As a result of SST, Zn-Mg-Al coated steels showed excellent corrosion resistance, better than GA and GI.
Abstract
Hot-dip Zn-Mg-Al coatings have a complex microstructure consisting of Zn, Al, and MgZn 2 phases. Its crystal structure depends on alloy content and cooling rates. Microstructure and corrosion resistance of these coatings might be affected by heat treatment. To investigate effect of heat treatment on microstructure and corrosion resistance of Zn-Mg-Al coatings, Zn-1.5%Mg-1.5%Al coated steel was heated up to 550 oC at a heating rate of 80 oC/s and cooled down to room temperature. At above 500 oC, the ternary phase of Zn-MgZn 2 -Al was melted down. Only Zn and MgZn 2 phases remained in the coating. Heat- and non-heat-treated specimens showed similar corrosion resistance in Salt Spray Test (SST). When a Zn-3.0%Mg-2.5%Al coated steel was subjected to heat treatment at 100 oC or 300 oC for 200 h and compared with GA and GI coated steels, the microstructure of coatings was not significantly changed at 100 oC. However, at 300oC, most Al in the coating reacted with Fe in the substrate, forming a Fe-Al compound layer in the lower part of the coating. MgZn2 was preferentially formed in the upper part of the coating. As a result of SST, Zn-Mg-Al coated steels showed excellent corrosion resistance, better than GA and GI.
참고문헌 (8)
- M-S. Oh, , Proc. Galvatech 2015, pp.201~ (2015)
- Il-Ryoung Sohn, "Anti-Corrosion Performance and Applications of PosMAC® Steel", Corrosion Science and Technology, 20, pp.7~ (2021)[DOI]
- Il-Ryoung Sohn, "Development of PosMAC® Steel and Its Application Properties", Korean Journal of Metals and Materials, 59, pp.613~ (2021)[DOI]
- P. Volovitch, "Understanding corrosion via corrosion product characterization: II. Role of alloying elements in improving the corrosion resistance of Zn–Al–Mg coatings on steel", Corrosion Science, 53, pp.2437~ (2011)[DOI]
- E. Diler, "Characterization of corrosion products of Zn and Zn–Mg–Al coated steel in a marine atmosphere", Corrosion Science, 87, pp.111~ (2014)[DOI]
- S. Schuerz, "Corrosion behaviour of Zn–Al–Mg coated steel sheet in sodium chloride-containing environment", Corrosion Science, 51, pp.2355~ (2009)[DOI]
- M. S. Oh, "Surface and cut-edge corrosion behavior of Zn-Mg-Al alloy-coated steel sheets as a function of the alloy coating microstructure", Metals and Materials International, 22, pp.26~ (2016)[DOI]
- "ISO 9227, Corrosion tests in artificial atmospheres - Salt spray tests", ~ (2017)