Laboratory scale investigation into the corrosion of copper in a sulphur-containing environment

The effect of temperature and gas composition on the corrosion rate and corrosion by-product of copper foil was studied by exposing it to sulphur (S2), S2 + hydrochloric acid (HCl) and hydrogen sulphide. The temperature was varied from 80 to 140 °C. Copper foil reacted with S2 to form CuS, Cu9S8 and Cu1.8S. Corrosion rates ranged from 9.6 μm/h at 110 °C to 0.5 μm/h at 140 °C. The presence of HCl caused pitting and enhanced the corrosion rate above 112 °C. Cu2S formed when copper was exposed to hydrogen sulphide gas. Sulphide scale that formed was friable and non-adherent.

► Sulphur reacts with copper to form CuS, Cu9S8 and Cu1.8S at temperatures between 80 °C and 140 °C.
► Sulphur corrodes copper foil at a rate of 54 mm/y at 80 °C and 80 mm/y at 110 °C.
► Chlorine significantly enhances the corrosion rate of copper by S2 above 112 °C.
► Copper foil at 140 °C reacts with H2S to form Cu2S.
► Non-adherent corrosion products form between copper and S2, S2 + HCL and H2S at 80 °C–140 °C.