Effect of TiO 2 Concentration on Microstructure and Properties of Composite Cu–Sn–TiO 2 Coatings Obtained by Electrodeposition.

In this work, Cu–Sn–TiO₂ composite coatings were electrochemically obtained from a sulfate bath containing 0–10 g/L of TiO₂ nanoparticles. The effect of TiO₂ particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu–Sn alloy, the Cu–Sn–TiO₂ composite coatings show rougher surfaces with TiO₂ agglomerates embedded in the metal matrix. The highest average amount of included TiO₂ is 1.7 wt.%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu–Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu–Sn–TiO₂ composite coatings have lower corrosion resistance as compared to Cu–Sn alloys, which is caused by the nonuniformity of the surface. [ABSTRACT FROM AUTHOR]