Corrosion of Cu in Antifreeze Solutions with Triazine- or Triazole-Type Corrosion Inhibitors for 3 Weeks

Abstract

The corrosion behavior of Cu in antifreeze solutions containing 2,4,6-Tris(5-carboxypentylamino)1,3,5-triazine, 2,4,6-Tris(11-carboxyundecylamino)1,3,5-triazine, 1-Aminomethyl(N′,N′-di(2-hydroxyethyl)tolutriazole, or 1-Aminomethyl(N′,N′-di(2-hydroxyethyl)benzotriazole as corrosion inhibitors were examined by immersion test for 3 weeks as well as potentiodynamic polarization tests before and after immersion test. The corrosion rate of Cu was as relatively high as 10−5 A/cm2 in antifreeze solution with the inhibitor (2,4,6-Tris(11-carboxyundecylamino)1,3,5-triazine) with a high molecular weight of 713 for a short time duration compared with antifreeze solutions using the other three types of inhibitors. However, the corrosion inhibition effect of this large molecule became prominent after 2 weeks, reducing the corrosion rate by about four orders of magnitude. Corrosion of Cu in the solution with inhibitors of high molecular weight of 440 or higher decreased gradually with time, while that in the solution with small molecules slightly increased over 3 weeks.