- Author
- Nguyen, T. | Lin, C.
- Title
- Development of a Method to Measure In Situ Chloride at the Coating/Metal Interface. Technical Note (Final).
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD Xiamen Univ., People's Republic of China
- Report
- NIST TN 1266, July 1989,
- Distribution
- Available from National Technical Information Service
- Keywords
- chlorides; coatings; metals; corrosion; blistering; electrodes; methodology; interfaces; electric potential; microelectronics; measurement; graphs (charts)
- Abstract
- One of the main reasons for the lack of a complete understanding of corrosion and adhesion failures of a coated metal is the lack of analytical instrumentation to probe the behaviors of corrosive agents at the coating/steel interface. A procedure has been developed based in microelectrodes for studying in situ the behaviors of potential and chloride ions in blister and at a coating/metal interface. The procedure requires an attachment of a double-barred Cl(-1) selective microelectrode at the coating/metal interface, thus allowing direct measurements of Cl(-1) concentration and corrosion potential changes at localized areas under a coating. Although it is intricate to prepare the microelectrodes, the procedure provided very useful information for mechanistic studies of corrosion under coatings, as well as for transport studies of Cl(-1) ions through a coating on metal. The procedure should also be very useful for studying the roles of Cl(-1) in localized corrosion. The utility of an inverted electrode microsampling method for studies of Cl(-1) in very small volumes such as blisters was also demonstrated.