Protection of copper and MNZH5-1 alloy in a neutral solution with an acid dye

The ability of the acid fuchsin (AF) dye to effectively inhibit the corrosion of copper and its alloy MNZh5-1 in a borate buffer with pH 7,4 containing 10 mmol/L NaCl, as well as in a more aggressive solution of 3,5% NaCl, was studied. Corrosion tests of copper in chloride-containing solutions showed that in a solution with 10 mmol/L sodium chloride, the introduction of 1 mmol/L AF provides a degree of protection Z = 97,7%, the introduction of 1,5 mmol/L AF completely protects copper from corrosion damage. In a solution with 3,5% sodium chloride, the degree of AF protection for the same concentrations is reduced to Z = 63,2%. Corrosion tests of the MNZh5-1 alloy in a 10 mmol/L NaCl solution with the addition of 1 mmol/L AF gives Z about 48%, which remains unchanged with a further increase in the concentration of acid fuchsin.