Various Parameters Affecting the Synthesis of the Hydroxyapatite Powders by the Wet Chemical Precipitation Technique

Abstract

Hydroxyapatite (HA) is the most well-known mineral among the bioactive ceramic materials. HA crystals can be described as the calcium and phosphorus source that provides the sufficient density and strength of the bone as well as the bioactivity. Wet chemical precipitation technique has practical advantages such as simplicity of the experimental stages, low reaction temperatures, and the possibility of controlling the chemical composition and microstructure properties of the final product with harmless by-products. Therefore in this study, HA powders were synthesized by the wet chemical precipitation technique where calcium hydroxide (Ca(OH)(2)) was used as the calcium source precursor while orthophosphoric acid (H3PO4) as the phosphorus source precursor. There are several factors -such as the pH value of the reaction solution, dropping rate of the acid solution into the alkaline solution, temperature of the reaction solution, the stirring rate, etc.-that play role in the wet chemical precipitation process and some of these parameters were investigated in this work. Each of these factors individually may influence the crystal and/or amorphous phases that are obtained at the end of the process. Preparation and reaction of the precursor solutions, aging of the final solution and precipitation, filtrating and washing, drying and eventually heat treating the precipitation are the main steps that were carried out throughout the synthesis process. X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transform Infrared Spectroscopy (FTIR) characterization studies were applied in order to determine the chemical, microstructural and molecular bonding properties of the powders produced. (C) 2015 Elsevier Ltd. All rights reserved.