Enhanced corrosion resistance and biofilm inhibition of TC4 with slight Cu addition against marine Pseudomonas aeruginosa.

Ti-6Al-4V (TC4) alloy is widely utilized as the structural material in marine industries owing to its low density, high specific strength, and favorable corrosion resistance. However, as biofouling drastically alters, some reported the major deleterious effect of bacteria has imposed a challenge to improve microbiologically influenced corrosion (MIC) resistance. A further opportunity for solving this problem is Cu micro-alloying, which was inspired by adding Cu for biomedical applications. Herein, a Ti-6Al-4V alloy with slight Cu addition (TC4-Cu) was exposed to 2216E media inoculated with Pseudomonas aeruginosa (P. A.), and then investigated compared to TC4. TC4-Cu exhibits lower corrosion current, more denser passive film, and lower weight loss with weaker pitting (a maximum pitting depth of 0.2 μm), compared to TC4 with a maximum pitting crater depth of 9.6 μm. Those demonstrated that the presence of Cu significantly improved the MIC resistance, and inhibited the proliferation of P. A., leading to a good antimicrobial efficacy against marine P. A. Moreover, besides the well-known bactericidal role, Cu ions were transferred to form Cu₂O and CuO, constituting protective corrosion products, and thus improving the anti-microbial properties of TC4-Cu.