Magnesium-based composites reinforced with graphene nanoplatelets as biodegradable implant materials

Magnesium (Mg) and its alloys are considered promising biodegradable implant materials because of their strength and ability to degrade naturally in the body. However, pure Mg degrades rapidly in the physiological environment which adversely affects its mechanical integrity before sufficient bone healing. In this study, a high energy ball mill was used to disperse 0.5 wt% zirconium (Zr) and 0.1 wt% GNPs in Mg powders. Ball milled powder mixtures were then cold pressed under 760 MPa into green compacts and sintered in an argon atmosphere at 610 °C for 2 h. Results indicated that the addition of Zr and GNPs to the Mg matrix significantly enhanced its compressive yield strength by 91% and reduced the corrosion rate by 48% and 68% in electrochemical polarization test and hydrogen evolution test, respectively, compared to pure Mg. The contributions of various strengthening mechanisms to the compressive yield strength of MMNCs were quantitatively predicted in conjunction with validation via experimental results. This study demonstrates the potential of GNPs as effective reinforcement in fabrication of MMNCs with improved mechanical and corrosion properties.