Processing of Ti/(HA+ZrO2) biocomposite and 50% porous hybrid scaffolds with low Young's modulus by powder metallurgy: Comparing of structural, mechanical, and corrosion properties

Abstract

Processing of titanium (Ti)-based implants with improved corrosion resistance and Young’s modulus close to that of cortical bone are receiving considerable attention in orthopedic and dental applications. Therefore, Ti matrix, hydroxyapatite (HA) and hydroxyapatite-zirconia (HA+ZrO2) reinforced composites were successfully produced using powder metallurgy as both bulk and 50% in vol. porous scaffold in this study. Microstructure, mechanical and corrosion properties of the bulk and scaffold composites were investigated comparatively. Scanning electron microscopy with attached an energy dispersive spectroscopy (SEM-EDS) and XRD diffraction analysis was used for the characterization of samples. Mechanical properties were determined by using micro Vickers hardness and compressive tests. Besides, the corrosion behaviours of the samples were determined in simulated body fluid (SBF) at 37 °C by using potentiodynamic scanning (PDS) tests. Room-temperature compression tests revealed that the bulk samples had higher values of Young’s modulus and yield strength in comparison to the scaffold samples where the lowest values of Young’s modulus and yield strength of 3 GPa and 6.93 MPa, respectively were obtained in the case of the Ti/(HA+ZrO2) composite scaffold. Moreover, in-vitro corrosion tests in SBF showed that the Ti/(HA+ZrO2) composite scaffold had higher corrosion resistance than the scaffold reinforced with only the HA phase. The corrosion mechanism of the bulk and scaffold samples was also elucidated by taking the microstructural analysis and phase compositional of the samples into account.