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Dezincification behaviour of three commercial α‐brasses (33–37% Zn) in acetate buffer solutions containing 0.5 M sodium chloride was studied by weight loss, solution analysis and electrochemical polarization over a period of time extended for four weeks. The corrosion behaviour in the same solutions without chloride was also studied to explore the role of chloride in the dezincification. The presence of chloride led to a severe dezincification, which increased as time increased in contrast to chloride‐free solutions. The corrosion rate, however, was insensitive to the presence of chloride. The dezincification factor in chloride solutions increased in the order: pH 7.0 < pH 8.5 < pH 2.4 (order of increasing Zn dissolution rate) while the corrosion rate followed the order: pH 8.5 < pH 7.0 < pH 2.4 (order of increasing O2 and H+ reduction rates). Corrosion and dezincification was not a simple function of % Zn in the alloy. A model was proposed to explain the autocatalytic dezincification in chloride solutions and important elements in the model are: the production, disproportionation and redeposition of cuprous chloride complexes, growth of a spongy copper layer on the corroding alloy and establishment of an increasing number of microgalvanic cells.

The inhibition behavior of chromate ions towards corrosion and dezincification of αbrass (Cu/Zn: 64/36) in acetate buffer solutions (pH 2.4, 7.0 and 8.5) containing 3% sodium chloride was studied. Weight loss and solution analysis were used for a long period (four weeks) and electrochemical polarization for a short period (one hour). Chromate accelerated corrosion and dezincification at pH 2.4 by acting as depolarizer but chromate suppressed efficiently the corrosion and dezincification at pH 8.5. At pH 7.0 the corrosion and dezincification suppressed in the presence of chromate but the inhibition action started to deteriorate at chromate concentration less than 0.005 mol/L. The inhibition effect is attributed to adsorption of chromate ions on the corroding surface and improvement of the passivity. Chromate led to an increase in the concentration of copper species in solution due to the formation of the more soluble CuCrO 4 than Cu 2 O, which contributed to the apparent suppression of dezincification.