The protective mechanism of the native rust layer on Cr-containing steels exposed to marine atmosphere

Autor: Zhang, Q. C., Wu, J. S., Zheng, W. L., Chen, J. G., Li, A. B.
Zdroj: International Journal of Materials Research: Zeitschrift fuer Metallkunde; January 2022, Vol. 93 Issue: 6 p590-594, 5p
Abstrakt: Cr-containing steel panels have been exposed to marine atmosphere for 2 years. The phase constituents and the microstructure of the rust layer have been characterized using scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), Raman spectroscopy, and transmission electron microscopy (TEM). Results show that there are many cracks and pores in the rust layer on the surface of mild steel exposed for 2 years, resulting in a higher corrosion rate. But a compact rust layer with a phase constituent of alpha Cr substitute ferrite oxyhydroxide (α-CrxFe1 –xOOH) has been formed on weathering steel panels with a Cr content more than 2 mass% exposed for 2 years. Furthermore, ion selective measurements showed that the rust layer of α-CrxFe1– xOOH can suppress the penetration of corrosive anions, and accordingly weathering steel panels have a lower corrosion rate in the marine atmosphere.
Databáze: Supplemental Index