A Contribution to the Production and Characterization of New Biomedical Coatings: Fluorohydroxyapatite Coatings

In order to improve the osteo-integration of the implant the state-of-art specifies the use of coatings such as hydroxyapatite (HA; Ca sub 5 (PO sub 4 ) sub 3 OH). The research deals now with new materials and modification of HA, in order to improve the stability and mechanical properties of the coatings or more generally of the implant. A promising material is fluorohydroxyapatite (FHA, Ca sub 5 (PO sub 4 ) sub 3 OH sub 1-x F sub x ). This paper addresses the production and characterization of Vacuum Plasma Sprayed Fluorohydroxyapatite coating for orthopedic endoprosthesis. The spray trials have been carried out on Ti6Al4V alloy substrates preventively blasted by means of corundum. In order to improve adhesion of FHA to titanium substrates two different titanium bond coats have been tested: the first with lower roughness and porosity named Type A and the second with higher roughness and porosity named Type B. A complete structural and mechanical characterization has been carried out: coating thickness, closed porosity and superficial porosity, microhardness, roughness have been measured.