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Effect of Cu content on exfoliation corrosion and electrochemical corrosion of A7N01 aluminum alloy in EXCO solution.

Authors :
He, Yaling
Wang, Xiaomin
Hu, Jie
Zhou, Qiang
Chen, Hui
Source :
International Journal of Modern Physics B: Condensed Matter Physics; Statistical Physics; Applied Physics. 7/30/2017, Vol. 31 Issue 16-19, p-1. 10p.
Publication Year :
2017

Abstract

The exfoliation corrosion (EXCO) sensitivities and electrochemical corrosions of A7N01 aluminum (Al) alloys with 0.074% and 0.136% Cu contents were investigated in EXCO solution. The exfoliation corrosion developed more rapidly for the alloy with 0.136% Cu by expressing higher exfoliation rate and deeper corrosion pits as observed by SEM and laser confocal scanning microscopy (LCSM). In EXCO solution, the alloy with 0.136% Cu content showed lower open-circuit potential (OCP) than the alloy with 0.074% Cu content. The alloy with 0.136% Cu content had bigger 'hysteresis loop' in cyclic polarization curve which meant lower self-passivation ability. In electrochemical impedance spectroscopy plot, its curvature radius and capacitance index were lower. The electrochemical test results revealed that the alloy with 0.136% Cu content showed more severe electrochemical corrosion than the alloy with 0.074% Cu content, consistent with the exfoliation corrosion results. The microstructures of two alloys were observed through optical microscopy (OM) and transmission electron microscopy (TEM). The continuous distribution of the equilibrium precipitate -MgZn2 on grain boundaries, the decreasing of the width of precipitate-free zone (PFZ) and the coarse Cu-Fe-Si-rich phase were responsible for the higher corrosion sensitivity of the Al alloy with 0.136% Cu than that of Al alloy with 0.074% Cu content in EXCO solution. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02179792
Volume :
31
Issue :
16-19
Database :
Academic Search Index
Journal :
International Journal of Modern Physics B: Condensed Matter Physics; Statistical Physics; Applied Physics
Publication Type :
Academic Journal
Accession number :
124314698
Full Text :
https://doi.org/10.1142/S0217979217440052