CeO2 based coating for high temperature oxidation protection

This paper investigates the influence of ceria (CeO2) coating on high temperature oxidation behaviour of 2.25Cr-1Mo steel. The superficial coating of CeO2 powder was prepared for experimental investigation. The isothermal corrosion study of uncoated and coated specimens was carried out in air oxidation environment at 973 K for 8 h. The corrosion rate and reaction kinetics were studied and the post corroded scales were characterised in scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction. The results clearly indicate that CeO2 coated specimen improves the high temperature oxidation resistance than uncoated specimen. The improvement of oxidation resistance in presence of CeO2 coating can be attributed to the formation of fine grained oxide on the scale, changed mechanism of scale growth from outer cation migration to inner anion migration and enhancement of scale adhesion with the substrate. The detail mechanism of the oxidation of CeO2 coated and uncoated specimen was further discussed in this paper.