Metal Ir coatings on endocardial electrode tips, obtained by MOCVD

Highlights: • Metal Ir coatings were deposited onto the endocardial electrode tips by MOCVD. • The formation of coatings with fractal-like morphology was achieved. • The metal coatings were electrochemically activated in acid media to form AIROFs. • The AIROF samples obtained are characterized by high capacitance. • MOCVD is the alternative method for deposition of Ir coatings for medical equipment. - Abstract: The present work demonstrates the application of the Metal-Organic Chemical Vapor Deposition technique to fabricate metal iridium coatings onto the pole tips of endocardial electrodes. Using iridium (III) acetylacetonate as a volatile precursor, the target coatings were successfully applied to the working surface of cathodes and anodes of pacemaker electrodes in the flow type reactor in hydrogen atmosphere at deposition temperature of 550 °C. The coating samples were characterized by means of XRD, SEM, Raman- and XPS-spectroscopies. The formation of non-textured coatings with fractal-like morphology and 7–24 nm crystallite size has been realized. The electrochemical properties of the coatings were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The charge storage capacity values of the electrochemically activated samples were 17.0–115 mC cm⁻² and 14.4–76.5 mC cm⁻² for measurements carried out in 0.1 M sulfuric acid and in phosphate buffer saline solutions, respectively. A comparison of some characteristics of the samples obtained with commercially available cathode of pacemaker electrodes is also presented.