Influence of the Addition of Niobium Pentoxide on the Structural Properties of Hydroxyapatite

The study focused on investigating the properties of composites made from natural hydroxyapatite (HAp, Ca10(PO4)6(OH)2) sourced from tilapia fish bones (Oreochromis niloticus) and niobium pentoxide (PNb, Nb2O5). The effects of PNb concentration and sintering temperature were examined. Composites were created using a constant pressure of 450 MPa following the formula (100-x)HAp + (x)PNb, with x varying in increments of 10%, and then sintered at temperatures ranging from 700 to 1300 °C. X-ray diffraction (XRD) analysis showed the formation of new phases based on the PNb concentration and temperature. Rietveld refinement confirmed a strong fit with experimental data, supporting the accuracy of the model parameters. Fourier Transform Infrared Spectroscopy with Photoacoustic Detection (FTIR-PAS) revealed the disappearance of the OH- functional group at 3572 cm-¹. Raman spectroscopy results were consistent with XRD findings. Scanning Electron Microscopy (SEM) showed complex microstructures influenced by composition, sintering temperature, and phase interactions, with liquid-phase sintering contributing to microstructural changes. Energy Dispersive X-ray Spectroscopy (EDS) provided semiquantitative analysis, detecting the primary elements Ca, P, and Nb, along with smaller amounts of Mg and Na. The Vickers Hardness (VH) measurements indicated that PNb concentration significantly affects the mechanical properties of the composite. The study suggests that HAp/PNb composites, influenced by temperature and PNb concentration, hold great potential for use in orthopedic and dental biomaterials.