Summary: | 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 Fe<sup>2+</sup> ions diffusion behavior in Fe<sub>3</sub>O<sub>4</sub>, Cr<sub>2</sub>FeO<sub>4</sub>, and FeAl<sub>2</sub>O<sub>4</sub> were studied by molecular dynamics method of Nudged elastic bond. As the result shown, Fe<sup>2+</sup> ions tended to diffuse through the vacancy at tetrahedral site in Cr<sub>2</sub>FeO<sub>4</sub> and FeAl<sub>2</sub>O<sub>4</sub>, but diffuse through the octahedral vacancy in Fe<sub>3</sub>O<sub>4</sub>. When temperature ranged from 1073 to 1325 K, the energy barrier of Fe<sup>2+</sup> ions diffusion in Cr<sub>2</sub>FeO<sub>4</sub> was higher than that of FeAl<sub>2</sub>O<sub>4</sub>, and both of that were still obvious higher than that in Fe<sub>3</sub>O<sub>4</sub>. A new anti-oxidation coating was prepared based on the inhibition of interface layer consisted of FeAl<sub>2</sub>O<sub>4</sub> to protect the carbon steel S235JR at 1200 °C for 2 h. The FeAl<sub>2</sub>O<sub>4</sub> region was formed and observed at the interface between coating and Fe element diffusion area, and the mullite phase was distributed outside of the FeAl<sub>2</sub>O<sub>4</sub> region. Comparing to the bare sample, the prepared coating exhibited an excellent anti-oxidation effect.
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