Magnesium-graphene nano-platelet composites: Corrosion behavior, mechanical and biological properties

Magnesium is preferably suited for implant applications since it has good biocompatibility and suitable elastic modulus close to the natural bone. However, it cannot be used under load-bearing conditions because of high degradation rate. In this study, Mg-based composite fabricated by semi powder metallurgy was reinforced by graphene nano-platelets (GNPs). Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDAX), transmission electron microscopy (TEM), Raman spectroscopy techniques and X-ray diffraction (XRD) analysis were used for microstructural, elemental and phase analyses. Microstructural evolution showed the uniform distribution of GNPs for the Mg-based composite with low GNPs concentration, but partial agglomeration could be seen in the composite containing a large amount of GNPs. Experimental results showed that hardness values increased with the addition of GNPs. Also, it showed better compressive strength at low concentrations of GNPs. The electrochemical corrosion behavior of the graphene-reinforced magnesium alloys was also investigated using electrochemical impedance spectroscopy (EIS). Evaluation of the antibacterial activity showed that the addition of GNPs to the Mg-based matrix can significantly inhibit the growth and infiltration of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The MCT loaded with 0.5 and 1 wt% GNPs did not represent cytotoxic behavior against the MG63 cells while further GNPs loading resulted in some toxicity. Overall, the results of this study demonstrate the potential application of Mg-1GNPs composite for implant application and bone infection treatment. (C) 2019 Elsevier B.V. All rights reserved.