Correlative Microscopy Workflow for the Characterization of TiN Coatings in Cardiac Rhythm Management Devices and Evaluation of Investigative Techniques
(Room Room 104-C)
02 May 19
12:00 PM
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12:20 PM
Tracks:
Coatings and Processes for Biomedical Applications
Electrochemically conductive coatings featured on pacemaker, defibrillator, and neurostimulator electrodes provide high surface area and low impedance to transfer electrical charge from the device to human tissue. Evaluation of the coating microstructure, whether it is titanium nitride (TiN) or iridium oxide (IrO2), is of peak importance as the coating microstructure affects performance and any undue failure carries numerous risks. However, microstructural evaluation is challenging given coating-feature length scales and there exists an overwhelming number of stand-alone techniques available for coating characterization. Electron microscopy, optical microscopy, IR spectroscopy, and X-ray tomography, among others, all present valid approaches but individually provide incomplete perspectives of the coating microstructures under investigation. However, a correlative workflow leveraging the most effective evaluation techniques could provide the most cohesive, complete, and efficient form of coating evaluation. In this study, a three-dimensional and non-destructive modality (3-D X-ray tomography) is coupled with a much higher resolution, yet destructive modality (FIB-SEM serial sectioning) to evaluate titanium nitride (TiN) coating microstructures as well as the efficacy of the involved investigative techniques. Correlating individual features for mutual probing across the two modalities led to the conclusion that 3-D X-ray tomography was sufficient for identifying the presence of irregularities and defects in the coating. As a result of the study, TiN coated components will benefit from the cost-savings of only needing one verification technique for initial quality assurance testing in a manufacturing setting, the time-savings of examining large-scale volumes of coated components, and the fundamental nature of non-destructive evaluation.