Effect of inhibitors on corrosion behavior of copper-nickel in concentrated lithium bromide solution at high temperature

The conventional mass-loss tests and the electrochemical techniques were used to study the inhibition action of LiOH and Na2MoO4 either individually or in different combination for copper-nickel alloy in boiling solution of 65% LiBr. It indicates that the corrosion rate of copper-nickel is decreased when LiOH or Na2MoO4 is added to the solution individually. LiOH concentration has a double-effect on the corrosion behavior of copper-nickel. Low concentration is benefit to forming oxide film. High concentration results in dissolution of oxide film. The optimal concentration of LiOH is 0.15 mol/L. The dissolution of copper-nickel is effectively prevented when adding 200 mg/L Na2MoO4 to boiling solution of 65% LiBr with 0.15 mol/L LiOH. The inhibition mechanism is considered that the films of Cu, Ni, Mo oxides and deposited nonprotective in soluble CuBr on the surface of metal could prevent Br- ion from absorption, which prevent alloy dissolving.