Effect of ZnO nanoparticles addition to PEO coatings on AZ31B Mg alloy: antibacterial effect and corrosion behavior of coatings in Ringer’s physiological solution

Abstract

In this paper, the plasma electrolyte oxidation (PEO) technique was applied to modify the AZ31B Mg alloy surface. Effects of various concentrations of ZnO nanoparticles into an electrolyte with nanoparticles of hydroxyapatite (HAp) on the antibacterial and corrosion behavior of coatings were studied. Potentiodynamic polarization tests were done in Ringer's electrolyte to study the coatings corrosion behavior. Results of XRD indicated that the provided PEO films mostly have phases of HAp, MgO, and Mg 3 (PO 4 ) 2 and ZnO. The results indicated that increasing the concentration of ZnO nanoparticles raised the thickness, roughness, and wetting angle and also enhanced the coatings antibacterial activity. The inhibition percentage of bacterial growth for the specimen with the highest concentration of nanoparticles (4 g/L) after 6 h against E. coli and S. aureus was 23.5% and 45.5%, respectively. The concentration of nanoparticles had no major effect on the porosity size of the ceramic coating. Moreover, adding ZnO nanoparticles declined the corrosion current density and raised the corrosion potential with regard to the metal substrate. The formed coating in the solution containing 1 g/ L ZnO nanoparticles had the highest corrosion behavior among all of specimens that led to a 970 multiplication corrosion resistance of AZ31B Mg alloy.

ZnO-based antimicrobial coatings for biomedical applications

“…ZnO NPs can be coated on the implant as antibacterial protection and anti-corrosion protection. For example, the PEO/ZnO NPs-coated AZ31B magnesium alloys implant exhibited reduction activity to S. aureus and E. coli colonies at pH of 13.2 [ 112 ]. The antibacterial performance can further be enhanced by illuminating the UV-irradiation to excite more electrons-holes pairs and generate radical species.…”

Recent Progress in Surface Modification of Mg Alloys for Biodegradable Orthopedic Applications

“…Wang et al conducted EPD on ZK60 alloy to prepare an HA layer on the porous MAO coating and obtained a dense and uniform HA layer enclosing the micro-porous deposition (Wang et al, 2020c). Seyfi et al (2021) investigated the effect of HA with various concentrations of ZnO (1-4 g/L) into the electrolyte during MAO. The coated samples showed an anodic shift of more than 800 mV and I corr reduction by more than three orders of magnitude.…”

Corrosion behavior of in‐situ synthesized ZnO‐containing coatings of AZ31B magnesium alloy by micro‐arc oxidation in simulated body fluids

“…[21][22][23][24][25][26] Adding Zn to microarc oxidized coatings to improve the structure and phase composition of coatings can effectively improve the corrosion resistance of magnesium alloys and expand their application in clinical fields. [27][28][29][30][31] The main methods for adding Zn to micro-arc oxidized coatings are the addition of ZnO nanoparticles and the in-situ synthesis of ZnO by micro-arc oxidation reactions. Nanoparticles are prone to uneven agglomerative distribution in coatings, and In-situ synthesis can effectively avoid the problem.…”

“…It plays a critical role in biological functions such as DNA synthesis, enzyme activity, nucleic acid metabolism, biomineralization, and hormonal activity, and also has excellent antibacterial properties [21–26] . Adding Zn to micro‐arc oxidized coatings to improve the structure and phase composition of coatings can effectively improve the corrosion resistance of magnesium alloys and expand their application in clinical fields [27–31] . The main methods for adding Zn to micro‐arc oxidized coatings are the addition of ZnO nanoparticles and the in‐situ synthesis of ZnO by micro‐arc oxidation reactions.…”