Sol–gel synthesis and characterization of hydroxyapatite nanorods

Abstract

In the present study hydroxyapatite (HA) nano-hexagonal rods with 70–90 nm diameter and 400–500 nm length are synthesized using a simple sol–gel route with calcium nitrate and potassium dihydrogenphosphate as calcium and phosphorus precursors respectively. Deionized water was used as a diluting media for HA sol preparation and ammonia was used to adjust the pH = 9. After aging, the HA gel was dried at 60 °C and calcined at different temperatures ranging from 300 to 700 °C. The dried and calcined powders were characterized for phase composition using X-ray diffractrometry, elemental dispersive X-ray and Fourier transform infrared spectroscopy. Rietveld analysis showed the calcined HA powders of high purity with a hexagonal unit cell structure. Calcination yielded HA nanopowders of increased particle size and crystallinity with increase in temperature. The particle size and morphology was studied using transmission electron microscopy. The aspect ratio (length to diameter ratio) of HA nanorods was measured to be between 6 and 7.