Open AccessCorrosion behavior of an AZ91D magnesium alloy under a heterogeneous electrolyte layer
Author(s) -
Yanhua Wang,
Cheng Zhen,
Zhan Zhang,
Zhencheng Tao
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0234981
Subject(s) - corrosion , electrolyte , materials science , magnesium alloy , alloy , polarization (electrochemistry) , metallurgy , magnesium , pitting corrosion , electrochemistry , electrode , chemistry
The corrosion behavior of an AZ91D magnesium alloy was investigated under a heterogeneous electrolyte layer by using electrochemical methods and surface analysis techniques. Dynamic polarization curves and morphological characterization were obtained at the center and near the edge zones under the electrolyte layer. The influence of the gas/liquid/solid three-phase boundary zone (TPB) on the corrosion behavior of the AZ91D magnesium alloy was discussed. The corrosion rate changed more significantly near the TPB zone than that at the other zones. The AZ91D alloy exhibited the characteristics of filiform corrosion together with shallow pitting corrosion. Different from the randomly distributed shallow pits, the filiform corrosion preferred to initiate near the TPB region and then progressively expanded adjacent to the edge of the electrolyte layer. The TPB zone played a vital role in determining the corrosion location, the corrosion morphologies and the corrosion rate of the magnesium alloy by influencing the mass transport process of carbon dioxide.