Morphological and electrochemical characterization of electrodeposited calcium phosphate coating

Hydroxyapatite coatings are currently the standard of the biomedical industry in order to promote osseointegration. An essential role is played by coatings based on calcium phosphate (CaP) deposited electrochemically (CaP-ED) thanks to the high reabsorption. For this reason, they represent an alternative to application by plasma spray. In this work an in vitro electrochemical characterization in solution simulating the human body fluids (SBF) was performed on Ti6Al4V samples coated with CaP-ED and after treatment in hot NaOH. The potentiodynamic tests showed a similar behaviour for the coatings. EIS tests show an increase in the value of the asymptote impedance module can be due to coating dissolution and reprecipitation processes that seal the porosities present initially. Samples coated with CaP-ED treated in hot NaOH showed initially differences in the behaviour compared to samples not treated, due to the different morphology and chemical composition that become neglectable for long exposition time.