Mechanical, in vitro corrosion and bioactivity performance of Mg based composite for orthopedic implant applications: Influence of Sn and HA addition

Abstract

The effect of addition of Sn and HA on mechanical, bio degradation and bioactivity behavior of Mg based composites fabricated by squeeze casting route was investigated in the present work. As-cast composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) for phase and microstructural studies respectively. Mechanical properties were evaluated by performing the compression test. Tafel, electrochemical impedance spectroscopy (EIS) technique and immersion tests were performed in simulated body fluid (SBF) to assess the in-vitro corrosion properties of the composites. In-vitro bioactivity test was also performed in SBF for 14 days of immersion period. Compression test results have showed that the lower amount of HA (5 wt.%) in Mg-1Sn and Mg-5Sn matrix would be better for the compression strength and composites weaken on further increase in HA content. The similar trend was observed in case of both mechanical and corrosion behavior indicating that 10 wt% of HA would be detrimental. It was concluded that the Sn acts as an effective alloying element for preventing the corrosion and HA is highly favorable for improving the bioactivity of Mg-Sn alloy matrix by depositing the calcium phosphate ions on the surface and up to 5 wt.% addition of HA and Sn would be optimum to enhance the mechanical, corrosion, bioactivity characteristics.

Keywords

• Biomaterials
• Metallic Composites
• Corrosion
• Orthopedic implants