Microelectrode Array for Electrochemical Sensing of Localized Corrosion

65243 Accurate descriptions of corrosion damage accumulation are needed to support the development of corrosion prediction models. This project will develop a multi-element, microelectrode array technology to resolve small-length-scale chemical and electrochemical processes involved in localized corrosion of metallic alloy systems. The arrays formed will be simulated heterogeneous microstructures with length scales relevant to corrosion in real alloy systems, capable of mapping potential, pH, and current distributions associated with passive or actively corroding surfaces. In Phase I, (1) A1-2024 microelectrode wires with diameters less than 6 ¿m were chemically milled, (2) Al-2024, Pt, and Ag microelectrode wires were fabricated into linear arrays with length scales 10-1000 ¿m, (3) the arrays were tested in corrosion environments, and (4) the data was compared to that obtained using state-of-the-art corrosion test methods. Phase II will (1) extend the approach to other engineering alloys of interest, (2) refine the chemical milling process and examine alternatives such as electrochemical milling, (3) design the arrays based on the results of mathematical modeling of electrochemical variations across surfaces, (4) refine the approach for fabrication of the arrays using the microelectrode wires, (5) test the microelectrode arrays in simulated corrosion environments, and (6) compare the corrosion data to that obtained by state-of-the-art methods. Commercial Applications and Other Benefits as described by the awardee: The specific groups in the commercial sector and federal government that should immediately benefit from this technology include the Department of Energy, the Department of Defense, universities, corrosion test equipment vendors, commercial aviation and automotive companies, and oil and gas companies.