In this study ionic adsorption was investigated of Ca and PO4 from Simulated Body Fluids (SBFx) at the surface of a Radio Frequent sputtered calcium phosphate coating. The relation between adsorption and heterogeneous nucleation of calcium phosphate was studied in doubly concentrated SBF. Two types of coatings were used, one with a high Ca/P ratio (1.6 CaPhigh), and one with a low Ca/P ratio (1.0 CaPlow). Ion coverages in the adsorption layer of CaPhigh coatings were twice as high as for the CaPlow coatings. The Ca/P ratio in the adsorption layer for CaPhigh samples was 1.3, which is the same value as for the formed precipitate. CaPlow samples were found to be inert in SBF2, showing a much higher Ca/P ratio of more than 2. Also, possible desorption of coating constituents during the induction time preceding precipitation was studied. It was found that at most a few percent of the outermost ionic layer of the coating entered the solution.
|Tijdschrift||Key Engineering Materials|
|Status||Gepubliceerd - 2003|