The nanocrystalline ceria sol-Gel coatings for high temperature applications

Sol-gel technology was utilized to produce nanocrystalline thin films of CeO2 on substrates with different oxidation resistance at high temperatures. After deposition, the coatings were composed of CeO2 crystallites with a size of 5 nm, randomly oriented on all the substrates. The annealing of gel deposited on Pt and Si substrates was accompanied by evaporation of water and other species and followed by growth of crystallites, without formation of any evident texture. Conversely, the annealing of coatings deposited on easy oxidizing substrates of Nr, Cr, or Ni−Cr alloys resulted in incorporation of CeO2 crystallites into growing native oxide, and in slowing the oxidation rate. Examples of the application of CeO2 ceramics as coatings deposited on selected metals and alloys for improving their oxidation performance are presented.