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

Abstract

Zinc and manganese were selected to develop magnesium alloys along with the bioactive ceramic β Tricalciumphosphate (βTCP) for biomedical applications fabricated by centrifugal casting. Microstructure, mechanical properties, corrosion properties, and biocompatibility of the Mg-2Zn-1Mn-xβTCP (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 βTCP significantly reduces the size of the grain. The experimental results of mechanical testing and corrosion studies show that the Mg-2Zn-1Mn-2.5βTCP 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 βTCP 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.