Active corrosion protection of aerospace aluminium alloys by lithium-leaching coatings

Abstract

For decades, scientists and engineers are searching for a safe and environmentally friendly alternative for the toxic chromate corrosion inhibitors in active protective coatings for the protection of aerospace aluminium alloys. In this search many different compounds have been investigated as leachable corrosion inhibitor, but no alternative with equal or better performance compared to chromates has been found yet. In 2010 it was discovered that organic coatings loaded with lithium-salts (Li) as leachable corrosion inhibitor provided very effective and promising corrosion inhibition on aluminium alloys when exposed to industrial accelerated corrosion tests. Initial investigations showed the formation of a corrosion protective layer on the aluminium alloy in a defect area, which appears to be a key feature of these Li-leaching coatings.