Development of Guidelines to Attenuate Galvanic Corrosion between Mechanically-Coupled Aluminum and Carbon-Fiber Reinforced Epoxy Composites Using Insulation Layers. Issue 10 (1st January 2015)

• Record Type: Journal Article
• Authors: Srinivasan, Raghu; Nelson, Jeffrey A.; Hihara, L. H.
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 10(2015)
• Page Start: C545
• Page End: C554
• Publication Date: 2015-01-01
• Subjects: 6061-T6 Aluminum -- atmospheric corrosion -- carbon-fiber reinforced polymer matrix composites -- corrosion model -- galvanic corrosion; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0611510jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The use of an insulating skirt to attenuate galvanic action between mechanically-coupled 6061-T6 aluminum (Al) and electrically conductive carbon fiber reinforced (CFR) polymer-matrix composites (PMCs) was assessed, analyzed and modeled. The galvanic-corrosion current as a function of time between the 6061-T6 Al and CFR PMCs for a range of insulative skirt lengths, ls, and sodium chloride (NaCl) salt loadings, m ′, in a humidity chamber at 30°C and 90% relative humidity (RH) were monitored. Polarization experiments were conducted on 6061-T6 Al and conductive CFR PMC electrodes to study the mechanisms governing galvanic corrosion in solutions ranging from 0 ppm chloride (Cl − ) to 20, 000 ppm Cl − concentrations. Based on the electrochemical characteristics of Al and the CFR PMC and the ohmic loss within the galvanic couple, a model was developed that related the galvanic corrosion rate ( iGalv ) to the value of ls / m ′, which is the ratio of the insulating skirt length to salt loading. Experimental data from the polarization experiments as well as data from monitoring the galvanic couples in the humidity-chamber galvanic experiments were used to generate plots of log ls / m ′ vs log iGalv, which can be used in design to determine proper skirt length for various environments (based on salt-loading levels) to limit the galvanic corrosion rate to a specified value.