Author/Authors :
Baradari، H. نويسنده Department of Metallurgy and Material Engineering, Iran University of Science and Technology, Tehran, Iran 16844 , , Amani Hamedani، H. نويسنده Department of Metallurgy and Material Engineering, Iran University of Science and Technology, Tehran, Iran 16844 , , Karimi Khoygani، S. نويسنده Department of Metallurgy and Material Engineering, Iran University of Science and Technology, Tehran, Iran 16844 , , Rezaie، H. R. نويسنده School of Materials Science and Engineering, Iran University of Science and Technology, Tehran, Iran. , , JAVADPOUR، J. نويسنده , , SARPOOLAKY، H. نويسنده ,
Abstract :
Ultra fine hydroxyapatite (HAp) powders with crystallite size in the range of 10-90 nm
were synthesized by chemical precipitation process using Ca(OH)2 and H3PO4 solutions as
starting materials. Molar ratio of Ca/P=1.68 was kept constant throughout the process and
alkaline condition for the reaction was maintained using ammonium hydroxide. The role of raw
material concentration on HAp crystallite size and morphology were investigated using X-ray
diffraction (XRD) and scanning electron microscope (SEM) techniques. The results revealed that
variations in crystallite size and morphology of synthesized HAp are strongly affected by the
concentration of acid solution. To study the sintering behavior of HAp particles, the powders were
pressed at 200 MPa using a uniaxial press. Sintering experiments were carried out at
temperatures of 1100, 1250 and 1300 °C with various soaking times at maximum temperatures.
XRD was also used in determining the phases present after sintering process. The results indicated
the decomposition of HAp into ?–tricalcium phosphate (TCP) and B–TCP phases at 1300 °C. The
microstructure of the sintered HAp ceramics was characterized by SEM.
