The effect of high temperature aging on the corrosion resistance, mechanical property and antibacterial activity of Cu-2205 DSS.

The effects of high temperature aging on the corrosion resistance, mechanical property and antibacterial activity of a copper-bearing 2205 duplex stainless steel (Cu-2205 DSS) were investigated. The results from scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and EDS analysis showed that after aging the proportion of γ phase in microstructure was increased and new σ phase and copper-rich precipitates were formed. The mechanical properties including hardness and tensile and yield strengths of the aged Cu-2205 DSS were significantly enhanced compared to the solution-treated Cu-2205 DSS as well as the 2205 DSS. Electrochemical measurements including electrochemical impedance spectroscopy, potentiodynamic polarization curves and potentiostatic polarization scan were performed to evaluate the corrosion behavior of the Cu-2205 DSS. It was found that aging increased the uniform corrosion resistance but had slightly adverse effect on the pitting corrosion resistance. Additionally, the antibacterial performance of aged Cu-2205 DSS was significantly improved compared to the solution treated Cu-2205 DSS, which was attributed to the more release of copper ions from the matrix that killed the bacteria cells and inhibited the biofilm formation on the surface. The above results suggest that Cu-2205 DSS after high temperature aging revealed good mechanical property, antibacterial performance, and corrosion resistance, which will further expand the application of duplex stainless steel in marine engineering fields.