Abstract
In this paper, a novel copper-nickel-aluminum multi-element alloy was prepared and the corrosion products, average corrosion rate, and polarization characteristics of the alloy at different corrosion duration and pH values were studied. The results have shown that as the corrosion duration increases, the corrosion products on the surface of multi-element copper alloys change. After etching for 72h, it was Cu2O; for 168h, it was a mixture of Cu2O and CuO; for 336h, it was mainly CuO. The longer the corrosion duration and the greater the pH value, the lower the average corrosion rate of the copper alloy. And copper alloys showed significantly lower corrosion rate in alkaline environments than that in acidic conditions. The corrosion process of the multi-element copper alloy can be divided into three stages, namely, the stage of generating the corrosion product film, the stage of forming a dense corrosion film on the surface of the copper alloy, and the stage of generating a stable passivation film on the surface of the copper alloy. In the alkaline condition, there was no oxide of Cu2+, and the final product was Cu2(OH)3Cl that would not destroy the formed Cu2O dense passivation film. The corrosion products on the alloy surface protect the internal alloy.
