A Mechanism of Anti-Oxidation Coating Design Based on Inhibition Effect of Interface Layer on Ions Diffusion within Oxide Scale

• Main Authors: Bo Yu, Ya Liu, Lianqi Wei, Xiaomeng Zhang, Yingchao Du, Yanhua Wang, Shufeng Ye
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Coatings
• Subjects: anti-oxidation coating; metal oxidation; ions diffusion; carbon steel
• Online Access: https://www.mdpi.com/2079-6412/11/4/454

In this paper, a mechanism of anti-oxidation coating design based on the inhibition effect of the interface layer on the diffusion of ions within oxide scale was introduced. The Fe²⁺ ions diffusion behavior in Fe₃O₄, Cr₂FeO₄, and FeAl₂O₄ were studied by molecular dynamics method of Nudged elastic bond. As the result shown, Fe²⁺ ions tended to diffuse through the vacancy at tetrahedral site in Cr₂FeO₄ and FeAl₂O₄, but diffuse through the octahedral vacancy in Fe₃O₄. When temperature ranged from 1073 to 1325 K, the energy barrier of Fe²⁺ ions diffusion in Cr₂FeO₄ was higher than that of FeAl₂O₄, and both of that were still obvious higher than that in Fe₃O₄. A new anti-oxidation coating was prepared based on the inhibition of interface layer consisted of FeAl₂O₄ to protect the carbon steel S235JR at 1200 °C for 2 h. The FeAl₂O₄ region was formed and observed at the interface between coating and Fe element diffusion area, and the mullite phase was distributed outside of the FeAl₂O₄ region. Comparing to the bare sample, the prepared coating exhibited an excellent anti-oxidation effect.