EFFECTS OF Nb ON CORROSION RESISTANCE OF 09CuPRe WEATHERING STEEL

摘要

The effects of Nb on the corrosion behavior of 09CuPRe weathering steel in the simulated industrial atmospheric environment were investigated by weight loss, X-ray diffraction, scanning election microscope and electrochemical workstation. The results showed that the steels exhibited better corrosion performance with increasing Nb concentration. The results of X-ray diffraction (XRD) indicated that the rust layers of the steels were composed of α-FeOOH, y-FeOOH, Fe_2O_3 and large amounts of amorphous compounds, the content of stable phase α-FeOOH in 09CuPRe-Nb steel was more than that in 09CuPRe steel. The addition of Nb was beneficial to the formation of dense and compact inner layer, which is the most important reason for the improvement of corrosion resistance of experimental steel. From the polarization curves, it can be seen that the corrosion current densities decreased with the addition of Nb into the 09CuPRe steel. In addition, the EIS results of these samples after circle soaking in 0.01mol/L NaHSO_3 solution, and being fitted by Rs(C 1 (Rr(C2(Rt)))) model, suggested that the corrosion resistance improved with the addition of Nb. All these observations suggested that the corrosion resistance of 09CuPRe weathering steel increased in the industrial environment with the addition of Nb.