Functionally graded calcium phosphate coatings produced by ion beam sputtering/mixing deposition

Ar+ ion beam sputtering/mixing deposition was used to produce thin calcium phosphate coatings on titanium substrate from hydroxyl-poly-calcium sodium phosphate (HPPA) acid HPPA + Ti targets. Three types of coatings (one type of monolayer coating and two types of functionally graded coating) were man ufactured. It was found that as-sputtered coatings were amorphous. No disti nct hydroxyl band was observed in the FTIR spectra, but new absorption band s were determined for CO32-, which resulted during the deposition process. Compositional gradients from the surface to the interior (i.e. adjacent to the substrate) were achieved for the functionally graded coatings. Post-dep osition heat treatment indicated that the bonding strength between the coat ing and the substrate was improved by the use of functionally graded struct ures. (C) 2001 Elsevier Science Ltd. All rights reserved.