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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2015, Vol. 36 ›› Issue (9): 3147-3154.doi: 10.7527/S1000-6893.2014.0305

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Electrochemical features of corrosion of 5A06 Al-Mg alloy in seawater

ZHANG Aiai, HE Jingjing, LIU Tianjiao, ZHANG Weifang   

  1. Science & Technology Laboratory on Reliability & Environmental Engineering, Beihang University, Beijing 100191, China
  • Received:2014-08-11 Revised:2014-10-28 Online:2015-09-15 Published:2014-11-29
  • Supported by:

    National Natural Science Foundation of China (37689501)

Abstract:

A corrosion experiment of 5A06 Al-Mg alloy immersed in seawater is conducted. The electrochemical impedance spectra and polarization curves for different periods are tested. Combining the microstructure, analyze the changing of these impendence spectra and polarization curves qualitatively. Three different equivalent circuits are proposed and the values of each equivalence element are fitted using the software of ZsimpWin based on a suitable equivalent circuit. Then the change rules are quantified. At the same time self-corrosion electric potential and self-corrosion electric current density are obtained by extend curve of polarization curves, which reflects the change of the instantaneous corrosion rate. The results show that double capacitive reactance arcs have appeared for a fresh 5A06 Al-Mg alloy. When the alloy is corroded for more than one day, the capacitive reactance arc is increased and then decreased as the immersion time is prolonged. The self-corrosion electric current density and the instantaneous corrosion rate are decreased and then increased. The Ecorr increases when it is corroded for one day, then gradually declines and ultimately presents the rising trend.

Key words: 5A06 Al-Mg alloy, corrosion in seawater, electrochemical impendence spectroscopy (EIS), polarization curves, rate of corrosion

CLC Number: