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

完整标题：锌铝镁基材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料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性能。许多钢产品都是基于热浸镀锌钢，涂有预处理、底漆和面漆。在过去的几年里，钢铁生产商已经开发出厚度更小的镀锌层-使用10微米的锌铝镁合金（扎姆），以便通过减少牺牲层的厚度来降低基材的总成本，提供与20微米厚锌层相同的腐蚀保护。在过去的十年里，行业合作伙伴，Becker Industrial Coatings Ltd.（Beckers）已开发并商业化了用于扎姆基材的无铬酸盐底漆，并取得了不同程度的成功。发现当涂覆在不同等级的扎姆基材上时，相同的底漆具有不同的耐腐蚀性。此外，异氰酸酯交联聚酯的耐腐蚀性一般比三聚氰胺交联聚酯的耐腐蚀性好。本项目的目的是调查和监测不同等级扎姆基材上卷材涂料的腐蚀失效机理。研究涂层在盐雾、Prohesion和Bohus Malmon自然场地中暴露时的行为，并与电化学阻抗谱（EIS）和扫描振动电极（SVET）相关联。拉曼或红外光谱可用于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.