Development of a Chromate-free, Corrosion Resistant, Eurethane Compatible Epoxy Primer for Cadmium and Zn-Ni Plated Steels

The aerospace industry has been under pressure to eliminate hexavalent chromium from its materials and processes. Non-chromated primers have been developed to protect aluminum substrates and are gaining acceptance in the industry. Unlike the chromated predecessors, these new primers do not work well on cadmium (Cd) and zinc-nickel (Zn-Ni) plated low alloy steels. UTC has developed a novel anti-corrosion technology and incorporated it into epoxy primers to provide corrosion protection for plated steels. This presentation will go over the tools and process used to develop the anti-corrosion additives and the testing to optimize their release and corrosion performance. Five generations of primers have been manufactured using the optimized anti-corrosion pigment formulations. Each generation has been tested extensively and further refined. Results of corrosion resistance, resistance to fluids, adhesion and impact over Cd and Zn-Ni plating will be presented.