Abstract:The effects of PMA/SbBr3 inhibitor on copper and copper-nickel alloy in 55%LiBr solution were investigated by chemical immersion and electrochemical measurements. The results indicate that in boiling 55%LiBr solution containing PMA/SbBr₃ inhibitor, corrosion rates of copper and copper-nickel alloy are 67.48μm/a and 38.14μm/a, respectively. Since both anodic and cathodic electrochemical reactions can be inhibited, PMA/SbBr₃ belongs to complex inhibitor. PMA has the effect of inhibiting hydrogen evolution and [PMo₁₂O₄₀]^3-, the anion of PMA, has a strong oxidizing effect. Sb³⁺ also shows an oxidizing effect. It may exist in LiBr solutions stably with PMA. Because of the synergistic effect of PMA and Sb³⁺, a protective film, comprising CuO, Cu₂O and Sb, formed on copper and copper-nickel alloy surface may prevent Br- from diffusing to the surface of metals. As a result, the anticorrosion performance of copper and copper-nickel alloy may be improved.

Key words: copper; copper-nickel alloy; lithium bromide; corrosion; inhibitor