Design of next-generation automotive corrosion protective coatings by improving inhibitor transport properties

保护性涂料行业正在应对寻找有毒防腐剂的成功替代材料的挑战。欧盟已将铬（VI）的使用指定为2019年的“日落”日期，之后将禁止使用。现在迫切需要找到新的、环境可接受的、具有同等或更好保护能力的腐蚀抑制技术。该合作是与汽车涂料公司巴斯夫汽车公司合作开发新的腐蚀抑制技术。现有技术的当前状态是部分基于磷酸盐的，并且仍然是有限的;这导致对开发智能释放颜料的性质的重大兴趣，其中腐蚀抑制物质被储存并且仅在侵蚀性腐蚀诱导剂存在下“按需”释放。此外，还需要改善抑制剂物质从涂层本体到特别需要它们的区域（例如暴露下层金属的缺陷）的传输。目前，只有有限量的源自紧邻缺陷的涂层的抑制剂可用于保护暴露的金属。通过在涂层中引入长距离渗透网络，可以增强缓蚀剂向含缺陷区域的输送，从而在暴露的金属处产生更有效的缓蚀作用，从而提高技术效率。研究工程师将：-使用目前最先进的磷酸盐基颜料和新型智能释放离子交换颜料，负载各种缓蚀物质，研究渗透涂层缺陷处的缓蚀效率。-通过改变涂层中所讨论的颜料负载组进行详细研究，以评估对抑制剂释放速度和随后缺陷“愈合”的影响。评估新型抑制剂输送系统，如纳米管储层、离子交换树脂和矿物质以及导电聚合物网络，作为在保护性有机涂层内引入抑制剂颜料的长距离渗透网络以输送到缺陷部位的一种手段。评估来自开发的优化系统的缓蚀剂物质的长距离迁移如何影响腐蚀驱动的有机涂层失效机制，即由于渗透缺陷附近的阳极破坏和/或阴极剥离引起的脱粘。这项工作的主要推动力是识别和开发技术上重要的轻合金表面的下一代保护涂层，通常为铝和可能的镁汽车合金等级，尽管最佳性能技术也可应用于钢的保护。该计划将利用该集团在先进的电化学扫描技术方面的杰出专业知识，结合高通量方法，以系统的方式量化涂层技术的保护效率，提供对腐蚀抑制过程的机械理解。确定这些机制将有助于开发新的，更有效的腐蚀抑制技术，可以纳入有机涂层系统。

The protective coatings industry is responding to the challenge to find a successful materials substitution for toxic anti-corrosion agents.Chromium (VI) use has been assigned a "sunset" date of 2019 by the European Union, after which its use will be banned. There is now an urgent need to identify new, environmentally acceptable corrosion inhibitive technologies showing equivalent, or better protective capability.The collaboration is in conjunction with the automotive coatings company, BASF Automotive, to develop new corrosion inhibitive technologies. The current state of the art technology is partially phosphate-based, and remains limited; this results in significant interest in exploiting the properties of intelligent-release pigments, in which corrosion inhibitive species are stored and only released "on demand" in the presence of aggressive corrosion-inducing agents. Furthermore, there is also a need to improve transport of the inhibitor species from the bulk of the coating, to the areas where they are specifically required (e.g. defects where the underlying metal is exposed). Currently, only a finite quantity of inhibitor originating from the coating in the immediate vicinity of the defect may be available to protect exposed metal. By introducing long-range percolation networks within the coating, it is thought that enhanced transport of corrosion inhibitor to defect-containing regions can produce significantly more effective corrosion inhibition at the exposed metal, as such providing enhanced efficiency of the technology.The Research Engineer will:- Investigate the efficiency of corrosion inhibition at penetrative coating defects using current state of the art phosphate-based pigments and novel smart-release ion-exchange pigments, loaded with various corrosion inhibitive species.- Carry out a detailed study through variation of discussed groups of pigment loadings within a coating, to evaluate the effect on speed of inhibitor release and subsequent defect 'healing'.- Assess novel inhibitor delivery systems such as nanotube reservoirs, ion exchange resins and minerals, and conducting polymer networks, as a means of introducing a long-range percolation network for inhibitor pigment within the protective organic coating for delivery to the defect site.- Evaluate how the long-range transport of inhibitor species from a developed, optimised system influences the mechanism of corrosive-driven organic coating failure i.e. due to de-adhesion originating from anodic undermining and/or cathodic disbondment in the vicinity of a penetrative defect.The main impetus of the work is to identify and develop next-generation protective coatings for technologically important light alloy surfaces, typically aluminium and possibly magnesium automotive alloy grades, although the best performing technologies may also be applied to the protection of steel. This program will exploit outstanding expertise in advanced electrochemical scanning techniques within the group, coupled with high throughput methodologies to quantify protection efficiency of the coating technology in a systematic fashion, providing mechanistic understandings of the corrosion inhibition processes. Identifying these mechanisms will enable the development of new, more effective corrosion inhibition technology that can be incorporated into organic coating systems.