Abstract
The effect of the galvanic corrosion process taking place between aluminium alloy (AA2024-T3) and carbon fiber reinforced plastic (CFRP) immersed in 0.05 M NaCl was studied using organic and inorganic compounds as corrosion inhibitors. Electrochemical approaches such as electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate efficiencies of 1,2,4-triazole (C2H3N3) and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) as corrosion inhibitors. The highest efficiency was reached for Ce(NO3)3.6H2O, with some improvement observed by adding C2H3N3 in a mixed inhibitor solution. The noise resistance (Rn) and polarization resistance (Rp) values calculated from ENA and EIS data showed almost identical behavior with different magnitudes but similar trends. Adsorption isotherm models estimated with fractional surface coverage (q) parameter were fitted better to Langmuir model for C2H3N3 and Temkin model for Ce(NO3)3·6H2O. The calculated values of Gibbs free energy suggested physisorption and chemisorption as spontaneous interactions between a metal surface and both inhibitors. Energy-dispersive X-ray spectroscopy (EDS) was carried out before and after immersing AA2024-T3 in the electrolyte, identifying rich zones in copper with cerium deposited over it and confirming the presence of rare-earth oxide deposition and oxide film products. The EDS analysis for CFRP revealed the deposition of Ce and Al particles over its surface after immersion in the electrolyte, especially in the areas rich in carbon.
Highlights
Hybrid structures have received great interest from the aerospace industry, especially in cases where a single material can not satisfy structural demands [1]
The electrochemical current noise (ECN) and the electrochemical potential noise (EPN) plots measured after 1 h (Figure 3) showed a decrement in their fluctuations when the inhibitor was added into the solution
The latter is attributed to the formation of a protective film on intermetallic sites, especially where there is copper contained in the sample, forming Cu-C2H3N3
Summary
Hybrid structures have received great interest from the aerospace industry, especially in cases where a single material can not satisfy structural demands [1]. Materials with a high strength-todensity ratio, such as carbon fiber reinforced plastic (CFRP) and aluminum alloys, are promising candidates for modern aircraft structures since when both are combined, the mechanical properties of a material are improved [2] Aluminum alloys such as AA2024-T3 in contact with other nobler materials (CFRP) tend to accelerate their electrochemically-driven degradation since they are more active in the galvanic series, showing an anodic behavior [3, 4]. A lot of efforts have been focused on analyzing mechanical properties of the hybrid structure AA2024-T3-CFRP, such as tensile and compressive properties, shear strength and damping behavior, and on establishing conditions under which this hybrid material could work without risk of damage during its operating life [8,9,10] Based on the latter, Payan et al did some experiments to find an adequate method for the analysis of the corrosion mechanism of aluminum matrix composite reinforced with graphite fibers, giving quantitative information on the morphology and kinetics of corrosion [11]. Sherif et al investigated different aluminum-graphite composites, showing the graphite concentration effect in the matrix, and observing an increment in the corrosion rate with reduction of the polarization resistance [12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Electrochemical Science and Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
