Ion adsorption on titanium surfaces exposed to a physiological solution

Changes in surface properties of titanium platelets exposed to a physiological solution Hanks’ solution.were studied by Auger electron spectroscopy and Attenuated Total Reflection Fourier Transform Infra Red spectroscopy for surface chemical composition analysis and by Scanning Force Microscopy for surface topography measurements. An adsorbed layer of calcium-phosphate was spontaneously formed on the titanium oxide surface and its thickness as well as the CarP ratio was found to increase with immersion time. After 71 days of immersion, the CarP ratio corresponded to that of brushite or monetite and after 6 months it was close to the value of hydroxyapatite. A higher CarP ratio was found for adsorption from solutions where the pH had been increased. After adsorption, the grains of the evaporated titanium substrate appeared slightly smoother because they were covered by a thin layer of calcium phosphate. A comparison between immersion in a Hanks’ solution and solutions containing only phosphates or only calcium ions, showed that the presence of phosphates is necessary for the adsorption of Ca-ions. q1999 Elsevier Science B.V. All rights reserved