Comparison on corrosion resistance and surface film of pure Mg and Mg−14Li alloy

To study different corrosion resistances and surface film types of hexagonal close-packed (HCP) pure Mg and body-centered cubic (BCC) Mg−14wt.%Li alloy in 0.1 mol/L NaCl, a series of experiments were conducted, including hydrogen evolution, mass loss, in-situ electrochemical testing combined with Ra...

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Bibliographic Details
Published in:Transactions of Nonferrous Metals Society of China 2020-09, Vol.30 (9), p.2413-2423
Main Authors: LI, Chuan-qiang, TONG, Zhi-pei, HE, Yi-bin, HUANG, Huai-pei, DONG, Yong, ZHANG, Peng
Format: Article
Language:English
Subjects:
corrosion resistance
electrochemical testing
in-situ electrochemical-Raman spectroscopy
Mg−Li alloy
surface film
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Summary:To study different corrosion resistances and surface film types of hexagonal close-packed (HCP) pure Mg and body-centered cubic (BCC) Mg−14wt.%Li alloy in 0.1 mol/L NaCl, a series of experiments were conducted, including hydrogen evolution, mass loss, in-situ electrochemical testing combined with Raman spectroscopy and microstructural observation. The results indicate that the corrosion resistance of pure Mg is superior to that of Mg−14Li, and the protective function of the surface films on both magnesium systems is elevated within 16 h of immersion in 0.1 mol/L NaCl. An articulated, thick, and needle-like surface film containing Li2CO3 on Mg−14Li, different from the typically thin, flaky Mg(OH)2 film on pure Mg, is confirmed via scanning electron microscopy (SEM). However, both surface films can be broken down at a high anodic over-potential. Thus, different corrosion resistances of the two Mg systems are ascribed to various protective films forming on their surfaces.
ISSN:1003-6326
DOI:10.1016/S1003-6326(20)65388-2