2023 Volume 72 Issue 10 Pages 259-268
The deposition behavior of films, corrosion products, during SCC on a phosphorus copper tube in an ammonia solution was investigated. It was found that Cu(OH)2 deposited on the tube surface and Cu2O deposited in the intergranular corrosion pit. The electrochemical behavior of the copper tube during SCC test indicated that pH in the intergranular corrosion pit is lower than that near the surface due to dissolution of phosphorus. Considering these environments, the difference of the deposited film type was explained by thermodynamics. It was also presumed that the Cu2O deposited thickly at the tip of the corrosion pit became the source of stress, leading to the occurrence of cracking.
