Effect of Cu on Corrosion Resistance of Zr-1Sn-0.35Fe-0.15Cr-0.10Nb Alloy in 400 C Oxygen-Contained Super-Heated Steam

In order to explore the effect of Cu on the corrosion resistance of Zr-1Sn-0.35Fe-0.15Cr-0.10Nb (mass fraction, %) alloy in 400 degrees C/1x10(-6) mu L/L oxygen-contained super-heated steam, Zr-1Sn-0.35Fe- 0.15Cr-0.10Nb and Zr-1Sn-0.35Fe- 0.15Cr-0.10Nb-0.05 alloy specimens were corroded in 400 degrees C/10.3 MPa/1x10(-6) mu L/L oxygen-contained super-heated steam by a dynamic autoclave. The microstructure of the oxide films and the valence state of the alloying element were studied by SEM, TEM, and XPS. The results show that the addition of Cu can improve the corrosion resistance of Zr- 1Sn- 0.35Fe-0.15Cr- 0.10Nb alloy; Cu mainly exists in the form of Cu and Cu+ in the oxide film; Cu can promote the transformation of Sn and Sn2+ into Sn4+ and from Fe2+ into Fe3+ in the oxide film; The reasons of Cu improving the corrosion resistance of Zr-1Sn-0.35Fe-0.15Cr-0.10Nb alloy are discussed from the aspects that the addition of Cu affects the oxidation behavior of alloying elements and inhibits the formation of pores and cracks in the oxide