The role of Ni content on the stability of Cu–Al–Ni ternary alloy in neutral chloride solutions

The effect of systematic increase of Ni content on the electrochemical behavior of the Cu–Al–Ni ternary alloys in neutral chloride solutions was investigated. Alloys with Ni contents, 5, 10, 30 and 45 mass% were used. The effect of chloride ions on the electrochemical behavior of these alloys was investigated. The presence of Al in the alloy increases its stability. An increase in the nickel content decreases the corrosion rate of the alloys. Conventional electrochemical techniques and electrochemical impedance spectroscopy, EIS, were used. The impedance measurements have shown that the increase of the Ni content and the immersion time of the alloys in the chloride solution increase the corrosion resistance of the alloys. The experimental impedance data were fitted to theoretical data according to a proposed model representing the electrode/electrolyte interface and the equivalent circuit parameters were calculated.

Graphical abstractThe increase of the Ni content in the ternary Cu-Al-Ni alloy decreases its corrosion rate.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Rcorr of the Cu–10Al–xNi alloy in neutral Cl− solutions increases with the Ni content. ► The alloy surface is loaded with Ni which prevents the Cu dissolution. ► Prolonged immersion of the alloy leads to formation of an adherent barrier layer. ► Al is essential for alloy light weight and the participation in barrier film passivity.