Electrochemical Impedance of Organic Coated Steel; Final Report. Correlation of Impedance Parameters with Long-Term Coating Performance.

摘要

This final report presents a general overview of the use of Electrochemical Impedance Spectroscopy (EIS) as it applies to the evaluation of organic coated steels exposed to aerated, artificial (ASTM) sea water. The testing was performed over roughly a 6-year span with some samples subjected to immersion testing for up to 4 years. Three project reports have been previously issued covering: (a) the initial test efforts, (b) a summary style literature search on the use of EIS and coated metals, and (c) an experimental correlation of the EIS parameters with the first 550 days of sample exposure in ASTM sea water. The data from the latter report have been critically reviewed, supplemented with data from the continued testing of the same sample set and have been reanalyzed using a modified equivalent electrical circuit. Keywords: Electrochemical impedance spectroscopy, Epoxy-polyamide coatings, Topcoat primers. (JS)