Synthesis and Characterization of Hot Extruded Magnesium-Zinc Nano-Composites Containing Low Content of Graphene Oxide for Implant Applications

Magnesium and its alloys have great capability for degradation in the body in a natural way, so they are one of the main new candidates as biodegradable implant materials. Of course, one of the disadvantages of pure Mg is its rapid degradation in the physiological environment that prior to bone healing has a negative impact on its mechanical integrity. In the present paper, a semipowder metallurgy coupled with hot extrusion process was utilized to fabricate Mg-6Zn/xGO (0.2 and 0.4 wt %) biocomposite. According to the microstructural characterization, graphene oxide (GO) nanosheets had uniform distribution in the composite, and also partial and gradually wrapped α-Mg grains were observed inside the Mg matrix. Results showed that the hardness and compressive yield of the Mg-6Zn/xGO composite were notably higher in comparison to pure Mg. It was revealed that the mechanical properties were enhanced because of the mechanisms of crack bridging, crack deflection, and crack tip shielding. The H2 evolution throughout their immersion in simulated body fluid (SBF) was decreased remarkably because GO nanosheets were distributed uniformly in the Mg matrix. In addition, less corrosion current density and higher corrosion resistance of the extruded Mg-6Zn and Mg-6Zn/GO in comparison to pure Mg were shown by electrochemical tests. Since the rate of the degradation process was decreased, the extruded Mg-6Zn/GO biocomposite presented great cytocompatibility. The research results show that GO nanosheets are efficient reinforcement to fabricate the extruded Mg-6Zn/GO biocomposite, which leads to the improvement of mechanical, corrosion and biological properties.