The failure mechanisms of organic coatings on Zinc Aluminium Magnesium substrates under exposure to natural conditions & accelerated corrosion environ

全标题：锌铝镁衬底上有机涂层在自然条件和加速腐蚀环境下的失效机理卷材涂层用于保护铝和钢免受自然环境的影响，因此附着力和防腐保护是保持良好耐腐蚀性的基本特性。许多钢铁产品都是以热镀锌钢为基础的，表面涂有前处理、底漆和面漆。在过去的几年里，钢铁生产商已经开发出厚度较低的镀锌层-使用10微米的锌铝镁(ZAM)合金，以通过减少牺牲层的厚度来降低基板的总成本，提供与更厚的20微米锌层相同的防腐性能。在过去的十年中，行业合作伙伴Becker工业涂料有限公司(Beckers)开发了ZAM基板的无铬底漆，并将其商业化，取得了不同的成功。相同的底漆在不同牌号的ZAM基材上涂覆时，具有不同的耐腐蚀性。此外，异氰酸酯交联型聚酯通常比蜜胺交联型聚酯具有更好的耐腐蚀性，本项目的目的是研究和监测不同牌号ZAM基材上卷材涂层的腐蚀失效机理。研究涂层在盐雾、Prohesion和Bohus Malmon的自然环境中暴露时的行为，并与电化学阻抗谱(EIS)和扫描振动电极(SVET)进行关联。可以使用拉曼光谱或红外光谱来识别测试过程中产生的腐蚀产物。

Full Title: The failure mechanisms of organic coatings on Zinc Aluminium Magnesium substrates under exposure to natural conditions and accelerated corrosion environmentsCoil coatings are used to protect aluminium and steel from natural environments, whereby adhesion and anticorrosive protection are the essential properties to maintain good corrosion resistance. Many steel products are based of hot dip galvanised steel coated with a pre-treatment, a primer, and a topcoat. In the last few years, steel producers have developed lower thicknesses of the galvanising layer-using an alloy of 10 microns of zinc aluminium magnesium (ZAM) in order to decrease the total cost of the substrate by reducing the thickness of the sacrificial layer, offering the same corrosion protection as thicker zinc layer of 20 microns.In the last decade, the industry partner, Becker Industrial Coatings Ltd. (Beckers) has developed and commercialised chromate free primers for ZAM substrates with varying success. The same primer was found to have varying corrosion resistance when coated on different grades of ZAM substrates. In addition, polyester cross-linked with isocyanate generally has better corrosion resistance than polyester cross-linked with melamine.The aims of the project are to investigate and monitor the corrosion failure mechanisms of coil coatings on different grades of ZAM substrates. To study the coatings behaviour when exposed in salt spray, Prohesion, and the natural site at Bohus Malmon and to correlate with electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode (SVET). Raman or IR spectroscopy could be used to identify the corrosion products produced during the testing.