Microstructures and bond strengths of the calcium phosphate coatings formed on titanium from different simulated body fluids

Calcium phosphate (Ca-P) coatings were deposited on Ti substrates by a biomimetic method from m-SBF and 10x SBF, respectively. Comparative study of microstructures and bond strengths of the Ca-P coatings deposited from those different SBFs was carried out. Effect of the surface toughness of the substrates on the bond strength of the Ca-P coatings was also studied. Scanning electron microscopy (SEM). X-ray diffractometry (XRD), Fourier transformed infrared spectroscopy (FTIR), inductive coupled plasma spectrometry (ICP) and thermogravimetry (TG) were used to characterize the Ca-P coatings. The bond strengths between the coatings and Ti substrates were measured using an adhesive strength test. Results indicated that the ionic concentrations of the SBFs and the surface toughness of the substrate had a significant influence on the fort-nation, morphology and bond strength of the Ca-P precipitates. The induction period of time to deposit a complete Ca-P layer from the m-SBF is much longer, but the Ca-P coating is denser and has higher bond strength than that formed from the 10x SBF. The Ti with a surface toughness of R-a 0.64 mu m and R-z 2.81 mu m favoures the formation of a compact Ca-P coating from the m-SBF with the highest bond strength of approximately 15.5 MPa. (c) 2008 Elsevier B.V. All rights reserved.