Penetration of corrosive species into copper exposed to simulated O2-free groundwater by time-of-flight secondary ion mass spectrometry (ToF-SIMS)

ToF-SIMS analysis of copper samples after exposures to simulated groundwater with and without sulfide addition was performed to investigate the penetration of corrosive species containing H, S, O, and Cl, into copper. Depth profiles show extent of penetration and 2D/3D images reveal local elemental distribution of the corrosive species at different depths inside copper. Pre-oxidation did not reduce the penetration while sulfide additional in groundwater and exposure at 60 °C significantly promoted the penetration. The extent of penetration of the corrosive species into copper demonstrates the need for risk assessment of complex corrosion forms such as sulfide-induced embrittlement and cracking. •ToF-SIMS measurements reveal penetration of S, O, H and Cl into Cu during exposure to anoxic ground water.•In-depth profiles and 2D/3D images of S, O, H and Cl show their spatial distribution inside the Cu microstructure.•Pronounced penetration occurs in the near surface region and deep local penetration proceeds at certain fast paths.•S, O, H and Cl segregate together inside Cu microstructure causing internal corrosion. It is enhanced by sulfide addition.•Exposure at 60 °C greatly accelerates the sulfide-induced corrosion and penetration of S, O, H and Cl into Cu microstructure.