Development and Characterization of a Zirconia-Reinforced Calcium Phosphate-Based Biocomposite

Abstract

Due to its improved bioactivity and biocompatibility, hydroxyapatite (HA) is a biomaterial that is frequently used for implant applications. However, hydroxyapatite ceramics can only reach their full potential if their comparatively poor mechanical qualities are strengthened, especially through the creation of composite materials. In this study, HA–zirconia composites were prepared and evaluated with the aim of developing calcium phosphate (CaP) composites reinforced with stabilized zirconia. Based on its exceptional mechanical qualities and biocompatibility, zirconia (ZrO₂) particles were chosen as the reinforcing phase.Natural bovine bone was used to extract hydroxyapatite, which offers a sustainable and eco-friendly source of phosphocalcic bioceramic material. To create dense ceramic bodies, composites with varying ZrO₂ percentages were agglomerated and then sintered for three hours at 1150 °C. The prepared composites were characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and instrumented hardness testing. XRD analysis showed that HA decomposed into calcium oxide (CaO) and β-tricalcium phosphate (β-TCP). During sintering, these decomposition products are combined with ZrO₂ to create calcium zirconate (CaZrO₃). Additionally, a non-uniform distribution of the yttria-stabilized zirconia (YSZ) phase within the HA matrix was shown by microstructural investigations, which affected the mechanical properties of the HA/YSZ composites.