Corrosion Behaviors of Al-Zr-Nd alloys in 3.5% NaCl Solution

Al-Zr-Nd alloys were prepared by arc melting and annealed at 500 ℃. The phase composition and corrosion behavior in 3.5% NaCl solution of the alloys were investigated by X-ray diffraction, metallurgical microscopy and electrochemical analysis. The results indicate that pitting corrosion occurred in the Al90Zr5Nd5 alloy which is mainly composed of Al solid solution, and expanded to Al substrate, resulting in selective corrosion. For other alloys, pitting corrosion was not observed, but the selective corrosion existed at defects, grain boundaries and easily corroded phases. Passivation was only observed in the procedure of anodic polarization of Al90Zr5Nd5 alloy. Al solid solution was priority dissolution and then the binary phases composed of Al and Nd due to galvanic corrosion, the corrosion resistance of the binary phases composed of Al and Zr was the highest.