Electrochemical Research on Stress Corrosion Cracking of Phosphorous Deoxidized Copper Tube

Abstract

The C-ring sample was immersed in an ammonia solution containing tetraammine copper ion. The corrosion potential and polarization curve of the sample were measured in order to electrochemically investigate the stress corrosion cracking mechanism of the phosphorus deoxidized copper tube. The phenomenon was observed in which the corrosion potential rapidly increased around 10 hours later. In addition, tarnished film was formed and SCC occurred after rapid increase in corrosion potential. From the potential-pH diagram, it was found that the sample fluctuated from the Cu（NH₃）^2＋ region to the Cu（OH）₂ region during the immersion test. However, it was clarified that SCC did not occur and the sample was dissolved under the solution conditions that were always present in the Cu（NH₃）^2＋ region.