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

摘要

The conventional mass- loss tests and the electrochemical techniques were used to study the inhibition action of LiOH and Na_2MoO_4 either individually or in different combination for copper-nickel alloy in boiling 65% LiBr solution. It indicates that the corrosion rate of copper-nickel is decreased when LiOH or Na_2MoO_4 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 Na_2MoO_4 to boiling 65% LiBr solution 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.