Corrosion behavior of low-alloy steel in Xinjiang's arid atmosphere: Divergent protective effects of Cr and Mn

Through systematic long-term atmospheric exposure, the corrosion performance and protective mechanisms of rust layers on low-alloy structural steels in Xinjiang's arid climate were comprehensively evaluated. Results demonstrate that MnO 2 and MnFe 2 O 4 can moderately enhance the compactness of the rust layer. However, the combined effects of strong wind-sand erosion and high diurnal temperature variations induce significant internal stresses within the rust layer, leading to crack formation. Notably, Cr alloying demonstrates superior corrosion mitigation effects through dual mechanisms: (1) catalytically facilitating the preferential formation of thermodynamically stable α-FeOOH, (2) generation of highly protective (FeCr 2 O 4 ), Cr(OH) 3 and Cr 2 O 3 .