Coatings for corrosion prevention based on rare earths

Conversion coatings are used extensively in metal finishing both as the principal mode of protection and a preliminary step for painting. Chromate-based conversion coatings have been a mainstay technology in this area for many years, but for environmental reasons and risk to health they are targeted for elimination. Rare earth-based technology, particularly cerium-based, has been extensively investigated as a replacement and shown considerable promise in a number of technologies, which are reviewed in this chapter.