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 temp eratures. After deposition, the coatings were composed of CeO2 crystal lites with a size of 5 nm, randomly oriented on all the substrates. Th e annealing of gel deposited on Pt and Si substrates was accompanied b y evaporation of water and other species and followed by growth of cry stallites, without formation of any evident texture. Conversely, the a nnealing of coatings deposited on easy oxidizing substrates of Ni, Cr, or Ni-Cr alloys resulted in incorporation of CeO2 crystallites into g rowing native oxide, and in slowing the oxidation rate. Examples of th e application of CeO2 ceramics as coatings deposited on selected metal s and alloys for improving their oxidation performance are presented.