Microstructure, mechanical property and corrosion behavior of co-continuous β-TCP/MgCa composite manufactured by suction casting

• The novel co-continuous β-TCP/MgCa composite was fabricated using suction casting technique.
• The microstructure, mechanical and corrosion properties of the composite were investigated.
• It showed the composite had compact structure and good interfacial combination.
• The ultimate compressive strength of the composite was near with the natural bone.
• And the corrosion resistance of the composite was better than that of the MgCa bulk alloy.

The co-continuous β-TCP/MgCa composite was fabricated by infiltrating MgCa alloy into porous β-TCP using suction casting technique. The microstructure, 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 tests. It was shown that the composite structure was compact and the interfacial combination between MgCa alloy and β-TCP scaffold was very well. The composite had an ultimate compressive strength of (147 ± 13) MPa, which was near with the natural bone (2–180 MPa) and about 1000-fold higher than that of the original porous β-TCP scaffold, but it still retained over half of the strength of the MgCa bulk alloy. The electrochemical and immersion tests indicated that the corrosion resistance of the composite was better than that of the MgCa bulk alloy, and the corrosion rate of the MgCa matrix alloy was quicker than that of the porous scaffold for the composite. The corrosion products of the composite surface were mainly Mg(OH)2, hydroxyapatite (HA) and Ca3(PO4)2.