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.