Passivation potential regulating corrosion resistance and antibacterial property of 316L-Cu stainless steel in different simulated body fluids

In this work, the corrosion resistance of 316 L-Cu stainless steel (SS) after passivation at different potentials was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The antibacterial property of passivated 316 L-Cu SS was also investigated by plate counting and live-dead cell staining combined with scanning electron microscope (SEM) observation. X-ray photoelectron spectroscope (XPS) was performed to analyse the composition of passive film. The results showed that the corrosion resistance increased with increase of the passivation potential from 600 mV to 750 mV, due to the enhancement of Cr2O3 and Cu(OH)(2) contents in passive film. When the passivation potential was increased to 900 mV, Cr(OH)(3) in passive film gradually dissolved and transformed to CrO42-, decreasing the stability of passive film. The higher compactness of passive film indicated a declined antibacterial performance.

Automated summary

The study found that the corrosion resistance of 316 L-Cu stainless steel improved with higher passivation potentials, due to increased Cr2O3 and Cu(OH)2 contents in the passive film. However, when the passivation potential reached 900 mV, the stability of the passive film decreased as Cr(OH)3 dissolved and transformed into CrO42-, leading to decreased antibacterial performance with higher compactness of the passive film.