High temperature oxidation behaviour of yttria ( Y₂O₃) coated low alloy steel

Abstract

This paper investigates the effect of yttria (Y₂O₃) coating on high temperature oxidation behaviour of low alloy 2·25Cr–1Mo steel. The superficial coating is Y₂O₃, which 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 by SEM, Energy-dispersive X-ray spectroscopy and X-ray diffraction. The results clearly indicate that Y₂O₃ coated specimen improves the high temperature oxidation resistance than uncoated specimen. The improvement of oxidation resistance in presence of Y₂O₃ coating can be attributed to the modification of grain structure of the scale, changed mechanism of scale growth and enhancement of scale adhesion with the substrate. The detailed mechanism of the oxidation of Y₂O₃ coated and uncoated specimen is further discussed in this paper.

Keywords:

• Low alloy steel
• Yttria ( Y₂O₃)
• Coating
• Oxidation

Acknowledgement

The authors are grateful to Director, CSIR-CMERI, Durgapur for his keen interest and encouragement to publish the paper.