Technical Note: Synergetic Effect of 8-Quinolinol and Benzotriazole on Preventing Dezincification of alpha-Brass (35.9% Zn) in Acid Chloride Solutions

Corrosion and dezincification of alpha-brass (35.9% Zn) in acid chloride solutions in the absence and presence of 8-quinolinol (C9H6NOH) (0.1 mM to 5.0 mM) were studied after 1-week immersion by mass loss and solution analysis. The severe dezincification was found to decrease substantially in the presence of 8-quinolinol, and complete prevention of dezincification was attained in the concentration range of 0.5 mM to 2.0 mM. The presence of 8-quinolinol, however, caused a pronounced increase in the corrosion rate. This disadvantage was completely overcome by adding 5 mM benzotriazole (C6H5N3). The following complementary action occurred: 8-quinolinol accelerated the dissolution of copper in the alloy more than that of zinc (dezincification was suppressed) while benzotriazole inhibited the dissolution of copper and zinc equally (general corrosion suppression).