Anti-bacterial property of Cold-Sprayed ZnO-Al Coating

The antibacterial behaviour of ZnO nanopowder and their composite coatings were investigated against E. Coli. ZnO nanopowder and Aluminum based ZnO composite powders were synthesized using in-house powder processing techniques. Bacteria culture results showed that ZnO nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of ZnO nanoparticle in their composite powders as well as increasing surface area of compacted pellets. These nanocomposite powders were subsequently used to generate antibacterial coatings using cold spray technology. The ratio of Al to ZnO in their composite powders were 80:20, 50:50 and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite Al-ZnO coatings were successfully deposited using cold spraying parameters of 15 Bars at air temperature of between 200-300 degrees C. These assprayed coatings of Al-ZnO composite powders with varying Al and ZnO ratios retained their inherent antibacterial property as verified from bacterial counting test. The results indicated that the antibacterial activity increased with increasing ZnO nanopowder concentration in the composite powder feedstock and cold sprayed coating.