2007 Volume 56 Issue 4 Pages 170-174
On the brazing part of copper tube and U bend in the fan coil unit, the solder was not corroded, and the soft copper tube that touches the solder has been corroded one-sidedly. Natural electrode potential of the solder and natural electrode potential of copper were measured on an unused brazing part sample in the tap water. The potential of the solder was about 100 mV higher than the potential of copper. It is guessed that the cause of corrosion is a bimetallic corrosion of which the solder is cathode and copper is anode.