Effect of benzotriazole, ammonia and sulphide on corrosion behaviour of brass in 0.5 m NaCl solution

The corrosion behaviour of brass (70Cu:30Zn) in 0.5 M NaCl solution and the effect of benzotriazole, ammonia and sulphide have been studied by cyclic voltammetry and polarization method. The copper dissolution takes place through the formation of CuCl, since the anodic reaction order with respect to Cl⁻ is one. The addition of benzotriazole did not affect the formation of cuprous chloride film, but decrease the copper dissolution reaction. The formation of cuprous chloride and its protective range have been found to be unaffected by the addition of ammonia. But the addition of sulphide broke down the cuprous chloride.