TOPOGRAPHICAL CHARACTERIZATION AND MICROSTRUCTURAL INTERFACE ANALYSISOF VACUUM-PLASMA-SPRAYED TITANIUM AND HYDROXYAPATITE COATINGS ON CARBON-FIBER-REINFORCED POLY(ETHERETHERKETONE)

In the present study, topographical characterization and microstructur al interface analysis of vacuum-plasma-sprayed titanium and hydroxyapa tite (HA) coatings on carbon fibre-reinforced polyetheretherketone (CF /PEEK) was performed. VPS-Ti coatings with high roughness values (R-a = 28.29 +/- 3.07 mu m, R-z = 145.35 +/- 9.88 mu m) were obtained. On t his titanium, intermediate layer HA coatings of various thicknesses we re produced. With increasing coating thickness, roughness values of th e HA coatings decreased. A high increase of profile length ratio, L-r, of the VPS-Ti coatings (L-r = 1.45) compared to the grit-blasted CF/P EEK substrate (L-r = 1.08) was observed. Increasing the HA coating thi ckness resulted in a reduction of the L-r values similar to the rough ness values. Fractal analysis of the obtained roughness profiles revea led that the VPS-Ti coatings showed the highest fractal dimension of D = 1.34 +/- 0.02. Fractal dimension dropped to a value of 1.23-1.25 fo r all HA coatings. No physical deterioration of the CF/PEEK substrate was observed, indicating that substrate drying and the used VPS proces s parameter led to the desired coatings on the composite material. Cro ss-section analysis revealed a good interlocking between the titanium intermediate layer and the PEEK substrate. It is therefore assumed tha t this interlocking results in suitable mechanical adhesive strength. From the results obtained in this study it is concluded that VPS is a suitable method for manufacturing HA coatings on carbon fibre-reinforc ed PEEK implant materials.