Effects of Antibacterial Treatment Temperature on the Properties of Copper-Bearing Antibacterial Duplex Stainless Steels

Antibacterial copper-rich phases such as epsilon-Cu were precipitated in copper-bearing antibacterial duplex stainless steels after antibacterial treatment. In this paper, the effects of antibacterial treatment on the corrosion resistance properties of copper-bearing antibacterial duplex stainless steels were investigated by electrochemical methods. The film-cover method was used to antibacterial tests. The results showed that as the antibacterial treatment temperature increased in the rang of 540 similar to 580 degrees C, the copper -rich precipitates grew faster and evolved from granular into rod-like. With the proportion of rod-like copper-rich phases in matrix increased, the resistant to pitting corrosion decreased and the positions of copper-rich phase precipitated were apt to become pitting nucleation source. The presence of epsilon-Cu and other copper-rich phases in passive film reduced the overall potential and passive film resistance, decreasing the stability of passive film. Antibacterial test showed that with the treatment temperature increased, the volume fraction and the uniformity of the distribution of copper-rich precipitates in the matrix first increased, then decreased, resulting in the changes in antibacterial properties of the steels, and 560 degrees C obtained the best antibacterial effect.