Physical properties and bioactivity of nanocrystalline hydroxyapatite synthesized by a co-precipitation route

In the present work, the hydroxyapatite (HA) fine powders were synthesized through the co-precipitation in conjunction with ultrasonic vibration with various pH. The effects of solution pH on the formation and morphology of the HA powders were investigated. The obtained powders and sintered samples were characterized using various techniques. The bioactivity test was also examined by using stimulate body fluid (SBF). Pure HA was obtained without any calcination process. The formation and particle morphology of pure HA powders varied with the pH of the solution, changing from needle like to round shape as the pH increased from 5 to 11. The pH 11 ceramic sample exhibited high thermal stability, while pure phase HA was still present after sintering at 1300 °C. The pH level also affected the properties of the studied ceramics. The bioactivity test revealed that the pH 8 sample showed a higher amount apatite layer on the surface than the other samples.