Oxidation of a novel CeO2‐dispersed chromium coating in wet air

Abstract

AbstractAn electrodeposited Ni–CeO2 composite was used as a “precursor film” for a novel CeO2‐dispersed chromium coating deposited using a traditional pack cementation method. The substrate was a carbon steel. For comparison, chromium coatings were also prepared on the untreated and pure Ni‐film‐treated carbon steel using the same pack cementation conditions. Oxidation in 5% O2 + 40% H2O + N2 at 900 °C showed that, compared to the CeO2‐free coating counterparts, the CeO2‐dispersed chromium coating exhibited greatly increased oxidation resistance, owing to the development of a denser and more slowly growing chromia scale. The slow growth of the scale was correlated with the CeO2 dispersion exerting the so‐called “reactive elemental effect (REE)” on oxidation. The oxidation mechanisms in wet air of the various types of coatings were compared to those in dry air and are fully discussed in this work.