Effects of Ce on Microstructure and Corrosion Resistance of Mg-9Gd-4Y-1Nd-0.6Zr alloy

The effects of Ce on microstructure and corrosion resistance of Mg-9Gd-4Y-1Nd-0.6Zr magnesium alloy was investigated by means of scanning electronic microscopy, x-ray diffraction, weight - loss test, electrochemical impedance spectroscopy and potentio-dynamic polarization test. The experimental results showed that Mg-9Gd-4Y-1Nd-0.6Zr alloy with 5% Ce had better corrosion resistance. Its corrosion current density decreased by 55.6%. Its corrosion potential moved positive about 141mV than that of Mg-9Gd-4Y-1Nd-0.6Zr alloy. It is believed that the corrosion resistance of the Mg alloy was enhanced by volume fraction and distribution change of the second phase particles. The microstructure study showed that the proper amount of Ce addition caused the segregation of the rare earth elements in the Mg alloy along grain boundary as network distribution, and the volume fraction of the second phase particles in the Ce containing Mg-9Gd-4Y-1Nd-0.6Zr alloy increased and their sizes decreased than those in Mg-9Gd-4Y-1Nd-0.6Zr alloy without Ce.