Effect of ceria coating on corrosion behaviour of low alloy steel

This paper investigates the effect of cerium oxide (CeO₂) coating on the high temperature corrosion behaviour of normalised and tempered 2·25Cr–1Mo steel in oxidation–sulphidation (SO₂+O₂) mixed gas environment. The CeO₂ coating of two different coating thicknesses (150 and 300 μm) is prepared for experimental investigations. The isothermal corrosion study of uncoated and different CeO₂ coated specimens is carried out in SO₂+O₂ environment at 973 K. The external scales of the post-corroded specimens are characterised after corrosion test by scanning electron microscopy and X-ray diffraction. CeO₂ coated specimens show higher corrosion resistance than uncoated specimen. The higher corrosion resistance of CeO₂ coated specimens is associated with excellent scale plasticity and adhesion. The detailed mechanism of the corrosion is discussed in the paper.