Some new discoveries on the structure of the rust layer of weathering steel in a simulated industrial atmosphere by STEM-EDS and HRTEM

Abstract

The rust layer (RL) structure of a weathering steel was characterized in a simulated industrial atmosphere by STEM-EDS and HRTEM. The amorphous phase was found intermingled with α-FeOOH nanograins in the inner RL, while rod-like γ-FeOOH was found in the outer RL. Moreover, the concentration of Cr was uneven in the inner RL, and Cr was enriched in the amorphous phase but depleted in the α-FeOOH nanograins. Additionally, Cu was enriched in the innermost RL near the rust-steel interface together with Cr to promote the formation of the amorphous phase.