Corrosion Mechanism in Artificial Sweat Solution of In-Bearing White Bronze Alloy

Corrosion properties of thin layers of a copper-tin-zinc-indium alloy (“white bronze”) were investigated in an artificial sweat solution indicating poor resistance properties. The coating degraded via pitting, generalized, and crevice corrosion, as evidenced by scanning electron microscopy-energy-dispersive x-ray analysis (SEM-EDX) investigation. The corrosion mechanism was investigated in situ by means of electrochemical impedance spectroscopy (EIS), and ex situ by x-ray photoelectron spectroscopy (XPS). These combined results demonstrate that the key point of the corrosion failure is the removal of the passive In-Sn oxides.