Study of the effect of ZnO nanoparticles addition to PEO coatings on pure titanium substrate: Microstructural analysis, antibacterial effect and corrosion behavior of coatings in Ringer's physiological solution

• Published in: Journal of alloys and compounds 2018-04, Vol.740, p.330-345
• Main Authors: Roknian, Masoud, Fattah-alhosseini, Arash, Gashti, Seyed Omid, Keshavarz, Mohsen K.
• Format: Article
• Language: English
• Subjects: Antibacterial effect; Antiinfectives and antibacterials; Coating effects; Corrosion; Corrosion currents; Corrosion effects; Corrosion resistance; Diffraction patterns; Electron microscopy; Emission analysis; Field emission microscopy; Infection; Microstructural analysis; Microstructure; Nanoparticles; Oxidation; Physiological effects; Plasma electrolytic oxidation; Protective coatings; Reduction; Scanning electron microscopy; Studies; Substrates; Titanium; Titanium alloys; X-ray diffraction; Zinc oxide; ZnO nanoparticles
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.12.366

In this work, a phosphate-based electrolyte, containing ZnO nanoparticles in concentrations of (0, 5, 10, and 15 g/L), was used to achieve coatings on pure titanium by using plasma electrolytic oxidation (PEO) method. Microstructure, phases, and chemical compositions of the coatings were investigated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) pattern and energy dispersion spectroscopy (EDS), respectively. In order to investigate the corrosion behavior, the samples were dipped in Ringer’s solution, and then potentiodynamic polarization test and electrochemical impedance spectrometry (EIS) were performed. Incorporation of ZnO nanoparticles into the coatings resulted in reduction in the number of pores, and modification of the coating microstructure, which consequently increased corrosion resistance. Also, addition of ZnO nanoparticles resulted in a decrease in the corrosion current density (93% reduction for the sample containing 15 g/L ZnO nanoparticles) in comparison with the uncoated titanium substrate. The results of antibacterial tests revealed that ZnO nanoparticles were able to effectively retain the Gram-positive and Gram-negative bacterial activities, and also, by increasing the concentration of nanoparticles, the intensity of antibacterial effect of the coating was increased. [Display omitted] •Ti was coated with the phosphate-based electrolyte containing ZnO nanoparticles (np).•Presence of ZnO np could severely modify the microstructure and fill the pores.•Improvement in antibacterial effects is caused by addition of different concentrations of ZnO np.•Increasing the concentration of np resulted in increasing resistance as well as decreasing icorr.•The results of EDS Mapping of the coatings indicated proper distribution of ZnO np.