Galvanic Corrosion of a Copper Alloy in Lithium Bromide Heavy Brine Environments

Galvanic corrosion of the copper alloy 84% Cu-15% Zn-1% Ni was studied in 55wt% lithium bromide (LiBr) environments. The galvanic couples studied were: 84% Cu-15% Zn-1% Ni-Ti2, 84% Cu-15% Zn-1% Ni-Ti7, 84% Cu-15% Zn-1% Ni-30% Cu-70% Ni, 84% Cu-15% Zn-1% Ni-Pb, 84% Cu-15% Zn-1% Ni-Ag, and 84% Cu-15% Zn-1% Ni-Sn. Potentiodynamic polarization measurements, open-circuit potential (OCP), and weight change measurements were carried out to evaluate the galvanic effect. Results indicated that Ti alloys and 30% Cu-70% Ni were the most passive alloys tested, and they behaved as cathodes. Although galvanic corrosion was expected, a negligible effect was measured because of an effective passivation layer on the surface of Ti alloys and 30% Cu-70% Ni. Pb, Ag, and Sn showed anodic behavior as compared to 84% Cu-15% Zn-1% Ni. As a result of the galvanic coupling, significant weight loss of these metals was measured. Sn was the most effective anode as compared to the other tested alloys; it acted as a sacrificial anode. Sn provided effective cathodic protection to 84% Cu-15% Zn-1% Ni in 55wt% LiBr environments at 140°C.