Role of N alloying in modifying rust layer characteristics and enhancing atmospheric corrosion resistance of high-Mn austenitic steel

The corrosion behavior and rust layer structure of two high-Mn austenitic steels (Fe−18.5Mn−7Cr−0.6C and Fe−18.5Mn−7Cr−0.6C−0.2N) were investigated in a simulated industrial atmosphere. N alloying improved the corrosion resistance, primarily through microstructural modifications in the rust layer structure. N alloying enhanced Cr enrichment (mainly as Cr 2 O 3 ) in the inner rust layer, resulting in greater thickness and compactness. Additionally, N alloying refined the α-FeOOH grains and increased the α-FeOOH/γ-FeOOH ratio, improving the protective properties of the outer rust layer.