Enhanced corrosion resistance through the synergistic effect of Cu2O oxide layers and fatty acids

The pure electrolytic copper foil was oxidized at 700°C under a gas pressure of 1/5,000 atm (20.27 Pa). The oxide layer consists of micrometer-sized Cu 2 O grains, which provide good adhesion to Cu and enhance corrosion resistance against acid, alkali, and salt water. However, partial corrosion still occurred in acid and salt water. To further improve corrosion resistance, a fatty acid known to bond with metal was considered a promising candidate. The bonding strength between the oxide and the fatty acid, as well as between the metal and the fatty acid, was analyzed using DFT calculations. The DFT calculation results showed that the bonding between Cu 2 O and any fatty acid is stronger than that between Cu and the fatty acid. Based on these findings, conventional canola oil, which contains various fatty acids, was applied to the surface of oxidized copper electrolytic foil. As a result, grain boundary corrosion was substantially reduced, leading to increased corrosion resistance in acid and salt water.