On the influence of sol–gel derived CeO2 coatings on high-temperature oxidation of Co, Ni and Cu

Abstract The effects of CeO2 coatings on high-temperature oxidation of Co, Ni and Cu have been investigated as a function of temperature at oxygen pressures from 1×10−4 to 1 atm. The oxidation mechanisms for Co and Cu are essentially unaffected by CeO2 coatings, whereas the oxidation rate of Ni decreases by approximately one order of magnitude. The oxygen pressure dependence does not change markedly with CeO2 coatings for any of the metals studied. For oxidation of Ni plus CeO2 coatings, the temperature dependence is less marked at lower temperatures, whereas essentially the same behavior is observed for Co and Cu with and without the coating. Differences in the effects of CeO2 coatings for the three metal systems have been attributed to the relative influence of grain boundary transport on the overall rates of oxidation.