Fabrication, bio-corrosion behavior and mechanical properties of a Mg/HA/MgO nanocomposite for biomedical applications

Abstract

The Mg/HA/MgO nanocomposites were fabricated with pure magnesium and the addition of different amounts of hydroxyapatite and periclase nanopowders using a blend-cold press-sinter powder metallurgy technique to improve the bio-corrosion and mechanical properties of the resulting material. Potentiodynamic polarization, immersion and mechanical tests were used to investigate bio-corrosion and mechanical properties of the nanocomposites produced. The compositions of the corrosion products and surface morphologies of the corroded specimens were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy. The corrosion resistance of the nanocomposites is shown to increase from 0.25kOcm2 to 1.23kOcm2 with the addition of 10wt.% MgO; additionally, decreasing the amount of HA from 27.5 to 12.5wt.% is shown to yield an increase in the compressive failure strain from 4.2 to 11.5%. The corrosion products of the composite surface are shown to be primarily Mg(OH)2, HA and Ca3(PO4)2. During immersion in SBF solution, the growth of the Mg(OH)2 nanorods on the nanocomposites increased the contact angle between the SBF solution and the substrate; as a result, the corrosion rate and hydrogen evolution rate decreased. The cell culture results indicate that Mg/HA/MgO nanocomposite is biocompatible with osteoblasts.