Antibacterial activities and corrosion behavior of novel PEO/nanostructured ZrO2 coating on Mg alloy
(1. Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia;
2. Department of Chemical and Biomilecular Engineering, Corrosion Engineering Program, The University of Akron, Akron, OH-44325, United States of America;
3. Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran;
4. Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran)
2. Department of Chemical and Biomilecular Engineering, Corrosion Engineering Program, The University of Akron, Akron, OH-44325, United States of America;
3. Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran;
4. Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran)
Abstract: Plasma electrolytic oxidation (PEO) was developed as a bond coat for air plasma sprayed (APS) nanostructure ZrO2 as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method toward Escherichia coli (E. coli) bacterial pathogens, respectively. The lowest corrosion current density and the highest charge transfer resistance, phase angle and impedance modulus were observed for PEO/nano-ZrO2 coated sample compared with those of PEO coated and bare Mg alloys. Nano-ZrO2 top coat which has completely sealed PEO bond coat is able to considerably delay aggressive ions transportation towards Mg alloy surface and significantly enhances corrosion resistance of Mg alloy in simulated body fluid (SBF) solution. Moreover, higher antibacterial activity was also observed in PEO/nano-ZrO2 coating against bacterial strains than that of the PEO coated and bare Mg alloys. This observation was attributed to the presence of ZrO2 nanoparticles which decelerate E. coli growth as a result of E. coli membranes.
Key words: Mg alloy; ceramics; coating materials; microstructure; scanning electron microscopy (SEM)