Sol gel derived porous hydroxyapatite coatings

The preparation of hydroxyapatite coatings on alumina substrates by a sol-gel method was investigated. A mixed ethanol solution of Ca(NO3)(2) . 4H(2)O and P2O5 was used as a dipping source. The samples were characterized by solid-state P-31 nuclear 5 magnetic resonance spectroscopy, differential thermal analysis, thermogravimetry, X-ray diffraction, scanning electron microscopy and infrared reflection spectroscopy. The coating obtained at 500 degrees C had good hydroxyapatite crystallinity, adhesive strength of about 10 MPa and dense morphology. The coating obtained at 750 degrees C also had good crystallinity and adhesive strength but porous morphology. (C) 1998 Chapman & Hall.