Microstructure and Corrosion Behavior of as-cast 90Cu-10Ni Alloys with Different Yttrium Content
Ying‐Hui Zhang, Chunmei Song, Yanfeng Cao, Hang Wang, Zhigang Wang, Bin Yang
Abstract
The microstructure and corrosion behavior of 90Cu–10Ni alloys with different contents of the rare earth (RE) element yttrium (Y) were investigated using electron probe micro analysis (EPMA), scanning electronic microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). The results showed that proper amount of Y could refine the secondary dendrite spacing of the as-cast microstructure. As the Y content increased, the number and sizes of the yttrium-rich oxysulfide inclusions increased. Meanwhile, the corrosion resistance of the alloys in a 3.5% NaCl solution immersed for 30 d improved first and then deteriorated with the increase in the Y content. When the Y content was 0.021%, the resistance of the inner film was greater than 1500 kΩ. This was attributed to the inhibitory effect of Y on the transformation from Cu 2 O to Cu 2 (OH) 3 Cl and the influence of Y on the diffusion of Ni.