| abstract |
A method for the early detection of electrochemical corrosion and coating degradation utilizing an inexpensive, in situ electrochemical metallic sensor for sensing coating and material degradation, particularly for materials such as aluminum 2024-T3, 7075, 6061, cold rolled steel samples, and coated metal structures such as automobiles, bridges, aircraft, and ships has been developed. The sensor utilizes AC Impedance or Electrochemical impedance spectroscopy (EIS) to acquire a precise, low-frequency impedance signature and is comprised of conductive ink deposited on a coating in the shape of the outline of a quadrilateral or other configuration. The resulting apparatus is comprised of a coated, metallic coupon used as a sensor, while a metallic grid electrode is deposited onto the steel coupon, thereby eliminating the need for a remote or counter electrode (i.e., reduction from a traditional, three-electrode system to a two-electrode system). Relying on the relatively lower impedance of the metallic grid electrode versus the coated metal, the electrodes are able to demonstrate a lower, interfacial impedance than the three-electrode testing system. This two-electrode approach eliminates the need for an electrolyte use in conventional, three-electrode AC Impedance testing and enables in-situ analyses of metallic and/or coating systems. |