What is galvanic corrosion and how can it be prevented?
Metals are rated according to their nobility ratings. When dissimilar metals are in contact with each other in the presence of oxygen and moisture, the more noble metal will corrode the less noble. Copper is one of the most noble of metals and must be separated from other less noble metals. Contact between dissimilar metals should always be avoided. If contact cannot be avoided, the adjacent surfaces should be painted with bituminous or zinc chromate primers or paints. Taping or gasketing with non-absorptive materials is also effective. Care should be taken to prevent the wash from copper surfaces onto adjacent, exposed less noble metal surfaces, since the traces of copper salts carried in the wash can accelerate the corrosion of less noble metals.
