Structure, mechanical property and corrosion behaviors of (HA + β-TCP)/Mg–5Sn composite with interpenetrating networks

In this paper, a novel (Hydroxyapatite + β-tricalcium phosphate)/Mg–5Sn ((HA + β-TCP)/Mg–5Sn) composite with interpenetrating networks was fabricated by infiltrating Mg–5Sn alloy into porous HA + β-TCP using suction casting technique. The structure, mechanical property and corrosion behaviors of the composite have been evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, electrochemical and immersion test. It is shown that the molten Mg–5Sn alloy has infiltrated not only into the pores but also into the struts of the HA + β-TCP scaffold to forming a compact composite. The microstructure observation also shows that the Mg alloy contacts to the HA + β-TCP closely, and no reaction layer can be found between Mg–5Sn alloy and scaffold. The ultimate compressive strength of the composite is as high as 176 MPa, which is about four fifths of the strength of the Mg–5Sn bulk alloy. The electrochemical and immersion tests indicate that the corrosion resistance of the composite is better than that of the Mg–5Sn bulk alloy. The corrosion products on the composite surface are mainly Mg(OH)₂, Ca₃(PO₄)₂ and HA. Appropriate mechanical and corrosion properties of the (HA + β-TCP)/Mg–5Sn composite indicate its possibility for new bone tissue implant materials.