Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution

The corrosion behavior of Mg-10Gd–xZn (x = 2, 6 wt.%) alloys in 0.5 wt.% NaCl solution was investigated. Microstructures of both the alloys consisted of (Mg,Zn)3Gd phase and lamellar long period stacking ordered (LPSO) phase. The morphology of the second phase at the grain boundary differed in both...

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Main Authors: A. Srinivasan, C. Blawert, Y. Huang, C.L. Mendis, K.U. Kainer, N. Hort
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2014-09-01
Series:Journal of Magnesium and Alloys
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S221395671400053X
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author A. Srinivasan
C. Blawert
Y. Huang
C.L. Mendis
K.U. Kainer
N. Hort
author_facet A. Srinivasan
C. Blawert
Y. Huang
C.L. Mendis
K.U. Kainer
N. Hort
author_sort A. Srinivasan
collection DOAJ
description The corrosion behavior of Mg-10Gd–xZn (x = 2, 6 wt.%) alloys in 0.5 wt.% NaCl solution was investigated. Microstructures of both the alloys consisted of (Mg,Zn)3Gd phase and lamellar long period stacking ordered (LPSO) phase. The morphology of the second phase at the grain boundary differed in both alloys: it was a continuous network structure in Mg–10Gd–6Zn, whereas it was relatively discrete in Mg–10Gd–2Zn. The dendrites were finer in size and highly branched in Mg–10Gd–6Zn. The corrosion results indicated that the increase in Zn content increased the corrosion rate in Mg–10Gd–xZn alloys. Micro-galvanic corrosion occurred near the grain boundary in both alloys initially as the grain boundary phase was stable and acted as a cathode, however, filiform corrosion dominated in the later stage, which was facilitated by the LPSO phase in the matrix. Severe micro-galvanic corrosion occurred in Mg–10Gd–6Zn due to the higher volume of second phase. The stability of the second phase at the grain boundary was altered and dissolved after the long immersion times. Probably the NaCl solution chemically reacted with the grain boundary phase and de-stabilized it during the long immersion times, and was removed by the chromic acid used for the corrosion product removal.
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spelling doaj.art-e041c9f509c64c3f99f78a44cbda08952024-04-16T12:12:30ZengKeAi Communications Co., Ltd.Journal of Magnesium and Alloys2213-95672014-09-012324525610.1016/j.jma.2014.08.002Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solutionA. Srinivasan0C. Blawert1Y. Huang2C.L. Mendis3K.U. Kainer4N. Hort5Helmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyHelmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyHelmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyHelmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyHelmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyHelmholtz-Zentrum, Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, GermanyThe corrosion behavior of Mg-10Gd–xZn (x = 2, 6 wt.%) alloys in 0.5 wt.% NaCl solution was investigated. Microstructures of both the alloys consisted of (Mg,Zn)3Gd phase and lamellar long period stacking ordered (LPSO) phase. The morphology of the second phase at the grain boundary differed in both alloys: it was a continuous network structure in Mg–10Gd–6Zn, whereas it was relatively discrete in Mg–10Gd–2Zn. The dendrites were finer in size and highly branched in Mg–10Gd–6Zn. The corrosion results indicated that the increase in Zn content increased the corrosion rate in Mg–10Gd–xZn alloys. Micro-galvanic corrosion occurred near the grain boundary in both alloys initially as the grain boundary phase was stable and acted as a cathode, however, filiform corrosion dominated in the later stage, which was facilitated by the LPSO phase in the matrix. Severe micro-galvanic corrosion occurred in Mg–10Gd–6Zn due to the higher volume of second phase. The stability of the second phase at the grain boundary was altered and dissolved after the long immersion times. Probably the NaCl solution chemically reacted with the grain boundary phase and de-stabilized it during the long immersion times, and was removed by the chromic acid used for the corrosion product removal.http://www.sciencedirect.com/science/article/pii/S221395671400053XMg–Gd–Zn alloysMicro-galvanic corrosionPolarizationElectrochemical characterization
spellingShingle A. Srinivasan
C. Blawert
Y. Huang
C.L. Mendis
K.U. Kainer
N. Hort
Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
Journal of Magnesium and Alloys
Mg–Gd–Zn alloys
Micro-galvanic corrosion
Polarization
Electrochemical characterization
title Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
title_full Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
title_fullStr Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
title_full_unstemmed Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
title_short Corrosion behavior of Mg–Gd–Zn based alloys in aqueous NaCl solution
title_sort corrosion behavior of mg gd zn based alloys in aqueous nacl solution
topic Mg–Gd–Zn alloys
Micro-galvanic corrosion
Polarization
Electrochemical characterization
url http://www.sciencedirect.com/science/article/pii/S221395671400053X
work_keys_str_mv AT asrinivasan corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution
AT cblawert corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution
AT yhuang corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution
AT clmendis corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution
AT kukainer corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution
AT nhort corrosionbehaviorofmggdznbasedalloysinaqueousnaclsolution