Electrochemically assisted formation of hydroxyapatite coatings on Nitinol

Various surface modifications have been applied to titanium and titanium alloys implants to improve their corrosion resistance and biocompatibility1. In this work Nitinol surface was modified with bioactive, bone-like hydroxyapatite coatings(HA), obtained by two deposition steps: electrochemical and chemical. Each of them has individual formation mechanism and deposited films posses different protection and biocompatible (bioactive) properties. The kinetics of the first step, nucleation of HA precursor film, was studied in situ using chronoamperometry (CA) and cyclic voltammetry (CV). The morphology, microstructure and barrier properties of HA coatings were characterized by field emission scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The chemical composition was examined using energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR).