Beneficial Effects of Zn, Al and Ni Addition on the Stability of Some Cu-Ternary Alloys in Acidic Solutions

Abstract

Copper-based alloys are important materials for many industrial applications but suffer from accelerated corrosion in acidic solutions. In the present work, we investigated the synergistic effects of Al, Ni and Zn as alloying elements on the electrochemical behavior of some Cu-ternary alloys in acidic solution of pH 2. The stability of some Cu-ternary alloys (Cu–10Al–10Zn, Cu–10Al–10Ni and Cu–10Ni–10Zn) in acidic solution (pH 2) was investigated using open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy. The electrochemical behavior of the investigated Cu alloys was dependent on the alloying elements. The results showed that the Cu–10Al–10Zn alloy is more stable than the other two studied alloys. The alloy surface was covered by a barrier layer protecting it from acidic corrosion. The thickness and resistance of the barrier film formed on the Cu–10Al–10Zn alloy increase with the increase in the immersion time. The corrosion process mechanism and the formation of barrier film were explained. The incorporation of Zn ions in the Cu2O barrier film leads to its stabilization, and the stability is enhanced by the presence of Al metal. Based on the analysis presented in the paper, it is concluded that the Cu–10Al–10Zn alloy is highly promising for application in the in acidic environments.