ABSTRACT
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
Copper-based coatings are known for their high antibacterial activity. In this study, nanocomposite Cu-Sn-TiO2 coatings were obtained by electrodeposition from an oxalic acid bath additionally containing 4 g/dm3 TiO2 with mechanical and ultrasonic agitation. Ultrasound treatment was performed at 26 kHz frequency and 32 W/dm3 power. The influence of agitation mode and the current load on the inclusion and distribution of the TiO2 phase in the Cu-Sn metallic matrix were evaluated. Results indicated that ultrasonic agitation decreases agglomeration of TiO2 particles and allows for the deposition of dense Cu-Sn-TiO2 nanocomposites. It is shown that nanocomposite Cu-Sn-TiO2 coatings formed by ultrasonic-assisted electrodeposition exhibit excellent antimicrobial properties against E. coli bacteria.
