Effect of Al on Corrosion Behavior of Imitation-Gold Cu-Zn-Ni-Sn Alloys in 3.5 wt.% NaCl solution

The corrosion behavior of imitation-gold Cu-Zn-Ni-Sn alloys with and without Al was investigated by means of color difference testing, static corrosion measurements, scanning electron microscopy analysis, electrochemical impedance measurements, and x-ray photoelectron spectroscopy analysis. The results showed that aluminum inhibited dissolution of Zn and Sn by the formation of an oxide film on the surface of the Cu-Zn-Ni-Sn alloy during corrosion, effectively improving its corrosion resistance. A transition of the corrosion product from Cu2O and Cu(OH)2 to CuO occurred on the surface of Cu-Zn-Ni-Sn-Al alloy, and the corrosion rate of the alloy decreased with increasing corrosion time due to the formation of the oxidation film and the hydrophobic effect of Zn5(CO3)2(OH)6 in the product layer.