Evaluating interface strength of calcium phosphate sol–gel-derived thin films to Ti6Al4 V substrate

The interface shear strength of Ca–P thin films applied to Ti6Al4 V substrates have been evaluated in this study using a substrate straining method—a shear lag model. The Ca–P films were synthesized using sol–gel methods from either an inorganic or organic precursor solution. Strong interface bonding was demonstrated for both film types. The films were identified as non-stoichiometric hydroxyapatite but with different Ca/P ratios. The Ca–P films were 1–1.5 μm thick and testing and analysis using the shear lag approach revealed a shear strength of approximately 347 and 280 MPa for Inorganic and Organic Route-formed films, respectively. Overall, the exceptional mechanical properties of Ca–P/Ti6Al4 V system along with the inherent advantages of sol–gel processing support continued studies to utilize this technology for bone-interfacing implant surface modification.