Smart Nanocomposite Coatings

The primary defense against the corrosion of steel is the diligent use of protective organic coatings loaded with soluble corrosion inhibitors. Not only are chromates toxic and increasingly regulated, but because these inhibitors are continually released from the coatings, they must be incorporated at very high levels into the coating. When the corrosion-inhibited coatings are exposed to water, the soluble inhibitors are slowly lost by leaching and migration, reducing the amount of chromates available to fight corrosion and introducing porosity that allows a greater flux of water to the surface. A more efficient corrosion control system would use smart corrosion inhibitors that release only when needed. Additionally, if the coating could indicate when corrosion is occurring, immediate maintenance steps can be taken to prevent further corrosion damage. In this Phase I TDA proposes to develop a multiple release corrosion inhibitor for steel. The corrosion process will trigger the release of the corrosion inhibitors from a nanoparticle carrier. While anchored, the corrosion inhibitors are non-leachable, but when released they migrate to self-heal the coating by passivating the metal surface. In our approach the corrosion process will also trigger a change in a corrosion indicator, which will provide passive sensing of the existence of corrosion. BENEFITS: Corrosion is a costly drain on the U.S. economy and military preparedness. Corrosion is estimated to cost the U.S. ~$275 billion annually (of which $20 billion is borne by the Department of Defense). Soluble chromates are the most effective corrosion inhibitors, but are toxic and heavily regulated. New more effective corrosion resistance coatings offer commercial benefits and applications across all sectors of the U.S. economy. They could be used for corrosion protection for metals employed in a wide range of applications including automotive, aerospace, bridges, and buildings.