SBIR Phase I: Hydrotalcite-Based Conversion Coatings for High Copper-Content Aluminum Alloys

这个小型企业创新研究一期项目是基于水滑石的形成，为高铜含量铝合金（如2024-T3）开发无铬转化涂层。化学转化涂层在保护铝合金方面有广泛的商业和军事应用，铝合金通常用作汽车和飞机制造的结构材料。这是由于它们具有优异的耐腐蚀性和作为涂料有效基底的能力。然而，传统的化学转化液含有六价铬和铁氰化物，这是剧毒的。铬酸盐转化涂料的持续使用已使金属精加工工业成为环境污染最重要的贡献者之一。因此，开发利用非铬酸盐化学品作为替代方法的转化涂层技术是非常可取的。该项目的关键是使用环保化学品形成具有优异耐腐蚀性的水滑石基涂料。在最佳温度下，在活化剂的帮助下进行转化涂层，以加快反应速度。形成的涂层将进一步用一种简单的有机化合物处理，以获得疏水和自愈特性，以增强其耐腐蚀性。所开发的非铬酸盐、水滑石基转化涂层工艺可以完全取代污染严重的铬酸盐转化涂层。这项新技术在经济上是可行的，并且对环境保护和人类健康非常有益。

9860554 This Small Business Innovation Research Phase I project is to develop chromate-free conversion coatings for high copper-content aluminum alloys, such as 2024-T3, based on the formation of hydrotalcite. Chemical conversion coatings have found widespread commercial and military applications in the protection of aluminum alloys, commonly used in automobile and aircraft manufacturing as structural materials. This is due to their excellent corrosion resistances and their abilities to serve as effective bases for paints. However, conventional chemical conversion baths contain hexavalent chromium and ferricyanide, which are highly toxic. The continued use of chromate conversion coatings has made the metal finishing industry one of the most significant contributors to environmental pollution. Thus, it is highly desirable to develop conversion-coating technologies utilizing non-chromate chemicals that can serve as alternative methods. The key to this project is the use of environmentally benign chemicals to form hydrotalcite-based coatings with excellent corrosion resistances. Conversion coatings will be performed with the aid of activators under optimal temperatures to accelerate the reaction rate. The formed coatings will be further treated with a simple organic compound to obtain hydrophobic and self-healing characteristics to enhance their corrosion resistances. The developed non-chromate, hydrotalcite-based conversion coating process could totally replace the polluting chromate conversion coating in metal finishing. This novel technology will be economically viable and be very beneficial with respect to environmental protection and human health.