Fabrication and characterization of graded calcium phosphate coatings produced by ion beam sputtering/mixing deposition

Ion beam sputtering/mixing deposition was used to produce thin calcium phos phate coatings on titanium substrate from the hydroxyapatite target. It was found that as-deposited coatings were amorphous. No distinct absorption ba nd of the hydroxyl group was observed in FTIR spectra of the coatings but n ew absorption bands were present for CO32-, which was brought about during the deposition process. Scanning electron microscopy revealed that the depo sited coatings had a uniform and dense structure. The calcium to phosphorou s ratio of these coatings varied between 2.0 and 8.0. Analyses of XPS data revealed that the coating could be divided into four distinctive zones. and a graded structure was achieved in the as-received coating. Scratch tests showed that the coatings adhered well to the substrate. (C) 2001 Elsevier S cience B.V. All rights reserved.