Effect of hydroxyapatite:zirconia volume fraction ratio on mechanical and corrosive properties of Ti-matrix composite scaffolds

Abstract

Ti-based scaffolds reinforced with zirconia and hydroxyapatite were produced successfully by a hybrid method with an eco-friendliness and low cost to obtain low elastic modulus (E) with sufficient physical, electrochemical and biological properties. The effect of simultaneous modification of the volume fraction of hydroxyapatite (HA) and zirconia (ZrO2) on scaffolds was investigated in terms of mechanical, corrosive, and antibacterial properties. Scanning electron microscopy with attached electron dispersive spectroscopy and X-ray diffraction were used for the characterization of scaffolds. Compression and electrochemical tests were performed to determine mechanical properties with detailed fracture mechanism and in-vitro corrosion susceptibility to simulated body fluid at 37 °C, respectively. Antibacterial tests were carried out by comparing the inhibition areas of E.coli and S.aureus bacteria. It was observed that the mechanical strength of the scaffolds decreased with increasing HA:ZrO2 volume fraction ratio. The lowest E was achieved (6.61 GPa) in 6:4 HA:ZrO2 composite scaffolds. Corrosion current density (Jcorr) values were calculated to be 21, 337, and 504 µA/cm2 for unreinforced Ti, 3:2 and 6:4 HA:ZrO2 reinforced scaffolds, respectively. The inhibition capacity of the 6:4 reinforced composite scaffold was found to be more effective against S.aureus bacteria than other scaffolds.