電気化学計測による銅管内部の残留カーボン皮膜評価法の開発

抄録

Copper tube is widely used as a heat exchanger for air conditioning systems because of its excellent thermal conductivity and corrosion resistance. However, the pitting corrosion may occur due to the carbon films formed on the inner surface of the copper tubes. In the present study, an evaluation method for the carbon film formed on the inner surface of copper tube was developed by the rest potential measurements. In this method, the rest potentials of inner and outer surface of copper tube are measured, and the difference in the rest potentials estimated from these measurements, ΔE, at arbitrary time is plotted against the amount of residual carbon on the inner surface of copper tube to obtain a two–dimensional diagram. A correlation was observed between ΔE and the amount of residual carbon in the diagram because the rest potential of the inner surface of copper tube was increased with increasing the amount of residual carbon. It indicated that the amount of residual carbon on the inner surface of copper tube can be evaluated from the two–dimensional diagram by obtaining ΔE.