Structural and mechanical characteristics of nanohydroxyapatite doped with zinc and chloride

AbstractIn this study, hydroxylapatite (HA) doped with Zn2+ and/or Cl− ions was synthesised by precipitation method and sintered at 1100°C for 1 h. Densities of the samples were measured by the Archimedes method. Zn2+ addition increased the density significantly, while Cl− increased the density insignificantly. Hydroxylapatite phase and inconsiderable amount of CaO phase were detected in some samples according to the X-ray diffraction results. Cl− added samples (2·5 mol.-%) increased the hexagonal unit cell volume of HA. Characteristic PO3−4 and OH− bands of HA were detected in Fourier transform infrared spectroscopy. Cl− related band was also observed at a wavenumber of 3497 cm−1. Grain sizes of the samples decreased with Cl− addition and increased with Zn2+ addition according to the SEM images. Zn2+ and Cl− addition improved the microhardness of pure HA. Fracture toughness of the samples decreased with Cl− and Zn2+ addition. When compared with other compositions, 2Zn2·5ClHA produced the best results in terms of mechanical properties.