SEDL / STP / STP866-EB / STP33774S

Electrochemical Impedance Tests for Protective Coatings

Mansfeld, F
Manager and member of technical staff, Rockwell International Science Center, Thousand Oaks, CA

Kendig, MW
Manager and member of technical staff, Rockwell International Science Center, Thousand Oaks, CA

Pages: 21    Published: Jan 1985

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Abstract

The experimental approach for carrying out electrochemical impedance measurements for coated metals is described. Models for the impedance behavior have been developed for different coating systems, and methods for the analysis of experimental impedance diagrams in terms of coating and interface properties and their changes during exposure to corrosive environments are discussed. The systems studied include polybutadiene coatings on bare and conversion coated steel and aluminum alloys, commercial chromate conversion coatings on aluminum alloys and sulfuric acid, or chromic acid anodized aluminum alloys. For the anodized aluminum alloys, suggestions for development of a quality control test are given.