Evaluation of Titanium Nitride and Iridium Based Pacemaker Electrode Coatings Using Electrochemical Impedance Spectroscopy

摘要

Pacemaker electrodes coated with TiN with two different morphologies and comparable thickness were tested using Electrochemical Impedance Spectroscopy. The impedance spectrum showed a strong dependence of the cutoff frequency on the morphology of the coating. A fit of the spectrum to the Randles model showed that the interface capacitance increased three times for a coating with favorable surface morphology. Similar measurements with Iridium coatings showed that the interface capacitance can be increased by electrochemical activation of the surface. A fit of this data to a Constant Phase Element model shows an increase of capacitance by a factor of two.