Structural and mechanical characteristics of nanohydroxyapatite doped with zinc and chloride

Uysal, I.
Severcan, F.
Evis, Zafer
In this study, hydroxylapatite (HA) doped with Zn2+ and/or Cl- ions was synthesised by precipitation method and sintered at 1100 degrees 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 PO43- 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.