Hydrothermal processing for increasing the hydroxyl ion concentration in hydroxyl depleted hydroxyapatite
In this work, HAp powder with a depleted hydroxyl ion concentration and thermally sprayed HAp coatings were used to find the best hydrothermal treatment parameters (i.e., vapour pressure, temperature and holding time). Hydrothermal treatment was carried out at 150 or 200 °C for 2 – 50 h by placing HAp powder or coating into a pressure vessel. Phases and functional groups were studied by X-ray diffraction and Fourier transform infra-red spectroscopy (FTIR), respectively. The changes in hydroxyl ion concentration were detected by calculating the OH/PO4 area ratio in the 500-700 cm-1 FTIR spectral region. Results showed that hydrothermal processing of HAp coatings at 200 °C for 20 hours produced the greatest increase in the hydroxyl ion concentration by about 30%.
Date
01.02.2018.
Keywords
Hydroxyapatite, Hydrothermal treatment, Fourier Transform Infra-Red Spectroscopy, Deconvolution, Hydroxyl ions
