Effects of Corrosive Factors of Copper Tubes for Carbon Film Dependent Pitting Corrosion Evaluation Test Solution

Abstract

It was known that one of the causes of pitting corrosion of copper tubes was residual carbon on the inner surface of copper tube. As a test for evaluating pitting corrosion resistance, electrochemical behavior was investigated using a mixture of corrosion promoting and corrosion inhibiting factors. In addition, immersion tests were conducted to confirm the effect of the compositional change of corrosive anions. There was a difference in electrochemical behavior and surface condition after the test due to the difference in the amount of residual carbon, and the possibility of pitting corrosion increased as the time for the spontaneous electrode potential to stabilize became shorter. Corrosive anions, especially sulfate ions, were considered to affect the electrochemical behavior.