Precipitation of hydroxyapatite film under dynamic conditions

Hydroxyapatite was synthesized by reacting Ca(HCO3)(2) with (NH)(2)HPO4 at 25 degrees C It was demonstrated that, for the crystallization of hydroxyap atite on a substrate as a coating, it is important to suppress the homogene ous nucleation in the bulk volume of the precursor solution. Heterogeneous nucleation on a sol-gel derived SiO2 surface was advantageous for the depos ition of film on a substrate under dynamic conditions. This approach led to the formation of a homogeneous, transparent coating (similar to 1 mu m) of hydroxyapatite on the sol-gel derived SiO2 surface on the glass, (C) 2000 Elsevier Science Ltd.