Characterization of the rust formed on weathering steel exposed to Qinghai salt lake atmosphere

The product formed oil weathering steel exposed to salt lake atmosphere for 12 months was investigated by X-ray diffraction (XRD), infrared transmission spectroscopy (IRS), scanning electron microscopy (SEM), electron probe micro analyzer (EPMA) and electrochemical techniques. The rust was mainly composed of beta-FeOOH, Fe-8(O,OH)(16)Cl-1.3 and a little gamma-FeOOH. Amorphous delta-FeOOH was only oil skyward surface. The rust layer suppressed anodic reaction and facilitated the cathodic reaction. The very small value of rust resistance R-r in this work indicated that the rust had poor protective ability. Cl element was rich in the whole rust layer and played an important role in accelerating the corrosion of weathering steel in salt lake atmosphere. (C) 2007 Elsevier Ltd. All rights reserved.