Short-term exposure of low-alloyed steels in Qinghai Salt Lake atmosphere

The rusts formed on carbon steel and weathering steel exposed in Qinghai Salt Lake atmosphere for 6 months were characterized by X-ray diffraction (XRD), infrared transmission spectroscopy (IRS), scanning electron microscopy (SEM), electron probe micro analyzer (EPMA) and electrochemical polarization techniques. The two kinds of steels showed the similar corrosion rate, corrosion product composition and electrochemical polarization behavior. Their rusts were mainly composed of β-FeOOH, Fe₈(O,OH)₁₆Cl_1.3 and a little γ-FeOOH. Cl^- played an important role during the corrosion process of low-alloyed steels. The alloyed elements Cr, Ni and Cu in weathering steel were detected in the rusts; however, they showed no remarkable protective ability.