Corrosion Prevention Goes Green
2014 R&D 100 Winner
The replacement of hazardous hexavalent chromium compounds in structural adhesive bond primers has been a problem for the aerospace industry. Because they are extremely vulnerable to localized corrosion, aluminum structures must be bonded with high-performance materials. The highly toxic strontium chromate additive is currently used to meet stringent safety standards, despite its heavy regulation throughout the world. But now there’s an effective alternative: EcoTuff. Developed by United Technologies Research Center and licensed and sold through Pratt & Whitney, EcoTuff is a multi-mode, non-chromated corrosion inhibitor for aluminum alloys. This pigment additive contains three agents that act synergistically to inhibit the localized corrosion of aluminum alloys. A molybdate oxyanion complex acts as an anodic corrosion inhibitor and a cerous ion is added as a cathodic corrosion inhibitor. The cerous ion is tightly bound to a citric acid molecule by three covalent bonds. This structure, a chelated cerium citrate complex, lets the inhibitors do their work without risks of unwanted reactions between them. EcoTuff has been licensed to 3M Company and is now used as the active corrosion inhibiting ingredient in 3M’s EW-5000ET aerospace adhesive bond primer.
Corrosion inhibitor for aluminum alloys
|The EcoTuff development team. Back row (l-r): Mark Jaworowski (United Technologies Research Center), Michael Kryzman (United Technologies Research Center). Front row (l-r): Xiaomei Yu (Sikorsky Aircraft Corporation), Weilong Zhang (United Technologies Research Center) and Promila Bhaatia (Pratt & Whitney).|
The EcoTuff Development Team
Eric Forbes, Principal Developer, 3M Corp.
Camelia Galos, Principal Developer, Pratt & Whitney
Mark Jaworowski, Principal Developer, United Technologies Research Center
Promila Bhaatia, Pratt & Whitney
Michael Kryzman, United Technologies Research Center
Xiaomei Yu, Sikorsky Aircraft Corporation
Weilong Zhang, United Technologies Research Center