Mechanical, corrosion and biological behavior of centrifugal casting processed Mg-2Zn-1Mn alloy reinforced with ß Tricalciumphosphate (ßTCP) for orthopaedic applications.

ABSTRACT

Zinc and manganese were selected to develop magnesium alloys along with the bioactive ceramic ß Tricalciumphosphate (ßTCP) for biomedical applications fabricated by centrifugal casting. Microstructure, mechanical properties, corrosion properties, and biocompatibility of the Mg-2Zn-1Mn-xßTCP (x = 0, 2.5, 5 wt%) alloys have been investigated by use of an optical microscope, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analysis, XRD analysis, mechanical testing, cell toxicity and blood hemolysis. A microstructure study has shown that the addition of ßTCP significantly reduces the size of the grain. The experimental results of mechanical testing and corrosion studies show that the Mg-2Zn-1Mn-2.5ßTCP alloy performs better among the three alloys developed, and the values in Vicker's microhardness, compressive strength, density, and porosity with 47.32HV, 238.22 MPa,1.75 g/cm3 and 2.28% respectively and the values of corrosion potential (Ecorr), corrosion current density (Icorr), linear polarization resistance (Rp) and corrosion rate (mm/year) of the Mg-2Zn-1Mn-2.5 ßTCP alloy in the outer and inner layers were found to be -1.46V, 2.71 ×10-5 A/cm2, 1677Ω, 0.62 mm/year and -1.41V, 3.92 ×10-6A/cm2, 4286Ω, 0.20 mm/year respectively. MTT Test and hemolysis experiments revealed that the magnesium alloy had no cell toxicity and good cytocompatibility, however, it produced hemolysis to the blood system. It was proposed that surface modification be used to improve the blood compatibility of the magnesium alloy for use in blood environments.