Microstructural study of aerosol-gel derived hydroxyapatite coatings.

Highly porous aerosol-gel derived hydroxyapatite (HAP) coatings have been prepared from calcium nitrate and phosphoric acid based sols. Precursor solutions were prepared by filtering the suspension formed during the ultrasonic slurring of the reactants mixture. The coatings deposited on Si wafers were studied after sintering at different temperatures by using Fourier transform infrared spectroscopy, X-ray diffraction, energy disperse microanalysis and scanning electron microscopy. The composition, structure and morphology of the coatings sintered at 650 degrees C were found to fit highly porous HAP. That is considered of great relevance since the deposition parameters are compatible with the processing of bioactive coatings on load bearing metallic substrates.