Einfluß von Kupfer auf das Korrosionsverhalten verzinkter Rohre in warmen Brauchwässern

Influence of copper on the corrosion behaviour of galvanized tubing in warm water systems Tests carried out with tap water (65°C) containing 0.1 to 0.3 mg/l Cu²⁺ have revealed that copper ions give rise to accelerated corrosion of tube walls. Corrosion takes place in the form of pitting. The intensity and frequency of pits increase as the copper content is increased and the pH value is decreased. Corrosion products formed on the zinc are predominantly a basic zinc carbonate, while copper is found in a coagulated form at the surface or embedded in the surface layer. The copper content of the corrosion products increases as the copper content of the water is increased and may attain up to 12.5%.