INVESTIGATION OF THE DISSOLUTION OF THE BIOCERAMIC HYDROXYAPATITE IN THE PRESENCE OF TITANIUM IONS USING TOF-SIMS AND XPS

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray ph otoelectron spectroscopy (XPS) analyses have been used to investigate the dissolution of hydroxyapatite in the presence of titanium chloride suggesting the substitution of titanium ions for calcium in the hydro xyapatite structure. The surface analytical data suggest that titanium was incorporated within the solid phase as titanium phosphate. Compar ison of relative ion intensities in the ToF-SIMS spectra reveals chang es in the composition of the surface chemistry of hydroxyapatite. Thes e relative ion intensities show that the maximum surface uptake of tit anium occurred at a solution concentration of 500 ppm titanium chlorid e for a time of incubation of 30 min. These data correlate with that o btained using XPS highlighting the semi-quantitative information which ToF-SIMS can provide. (C) 1997 Elsevier Science Limited. All rights r eserved.