Print Email Facebook Twitter Effect of Chemical Composition and Microstructure of Zn and Al-based Coatings on Electrochemical Response in Corrosive Environments Title Effect of Chemical Composition and Microstructure of Zn and Al-based Coatings on Electrochemical Response in Corrosive Environments Author Mutgi, A.V. Contributor Mol, J.M.C. (mentor) Faculty Mechanical, Maritime and Materials Engineering Department Materials Science and Engineering Date 2015-08-28 Abstract Hot formed steels are witnessing an increasing use in safety critical and structural parts for automobiles due to their high strength, light weight and absence of springback, due to which understanding the corrosion behaviour of coated products for hot forming is crucial to increase their stronghold in Body-In-White (BIW) applications for automobiles. Currently, aluminium alloy coatings are the preferred choice due to their high temperature stability and low density. However, with OEM’s increasing interest in endowing sacrificial protection to hot formed components, zinc coatings are also making a foray into the product portfolio of steel solution providers. In this study, the corrosion performance of Galvanized Iron (GI), MagiZinc® and Usibor® AlSi coatings for hot press forming was investigated with the help of electrochemical techniques. Galvanostatic testing was used to analyze the response of the coatings to austenitization. The corrosion performance and resistance to pitting was assessed using Cyclic Voltammetry and the corrosion mechanism was characterized through Scanning Electron Microscopy (SEM) and Glow Discharge Optical Emission Spectroscopy (GDOES). The results indicated up to a five-fold improvement in coating thickness for the Zn coatings after hot forming. MagiZinc® containing Mg and Al 1.6 wt. % each was found to have better corrosion resistant properties, as the alloying additions rendered it a better passivation ability compared to conventional GI. Usibor® AlSi developed an aluminium alloy coating layer after hot forming, that possessed only limited sacrificial ability and displayed a vulnerability to pitting. Thus, in terms of the quality of cathodic protection offered to the substrate, the Zn coatings were found to have an upper hand compared to the AlSi coating. Subject corrosionhot formingpress hardened steelscoatings To reference this document use: http://resolver.tudelft.nl/uuid:ec1ffb71-5f1b-4730-89ae-45b81efbf5ec Embargo date 2020-08-28 Part of collection Student theses Document type master thesis Rights (c) 2015 Mutgi, A.V. Files PDF Effect_of_Chemical_Compos ... nments.pdf 3.2 MB Close viewer /islandora/object/uuid:ec1ffb71-5f1b-4730-89ae-45b81efbf5ec/datastream/OBJ/view