Calcium phosphate coating on Ti6Al4V by autocatalytic route

The authors present a study for the first time, an alternative coating route based on an autocatalytic process on metal alloy, to induce Ca–P layer in a way similar to the process of natural bone formation. Ti6Al4V (High-grade titanium aluminium vanadium alloy) substrates were subjected to several pretreatment steps, such as alkali and heat treatments. Afterwards, they were immersed in autocatalytic baths under certain conditions to form Ca–P layers. To check their biochemical stability, the treated substrates were immersed in SBF (simulated body fluid) for 4 days. The biolayers were investigated by FESEM-EDS (field emission scanning electron microscope—energy dispersive x-ray spectroscopy) and FT-IR (Fourier trasform infra-red spectroscopy), before and after immersion in SBF. Biochemical analyses were also performed to evaluate the calcium and phosphorous content in SBF. In autocatalytic baths, Ca–P precipitates on the pretreated substrates after only 2 h. Moreover, after being immersed for 4 days in SBF, the phosphates begin to dissolve and to be replaced by carbonates.