Effects of light pre-deformation on pitting corrosion resistance of copper-bearing ferrite antibacterial stainless steel

Ferrite antibacterial stainless steel has found wide potential applications in many fields, such as kitchen appliances, medical and public equipments. Good corrosion resistance is one of required properties for these applications. This study aims to improve the pitting corrosion resistance of ferrite antibacterial stainless steel, without a notable loss in the antibacterial property. Light pre-deformation with a reduction of 10–20% was performed on the steel and the pitting corrosion resistance in 3.5% NaCl solution was measured by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It is found that pre-deformation improves the pitting corrosion resistance to an extent, without notably sacrificing the antibacterial property. Refined epsilon copper precipitates and suppressed copper surface segregation might explain the improvement of pitting corrosion resistance. The refinement mechanism is revealed that pre-deformation brings about a modification both in precipitation mechanism and growth kinetics of epsilon copper. Copper surface segregation is suppressed by the drag force exerted on the copper atoms by high-density dislocations which are induced by pre-deformation. Light pre-deformation is expected to increase the affordability of ferrite antibacterial stainless steel.