Passivation and potential fluctuation of Mg alloy AZ31B in alkaline environments

Shengxi Li; Ana C. Bacco; Nick Birbilis; Hongbo Cong

doi:10.1016/j.corsci.2016.08.022

Passivation and potential fluctuation of Mg alloy AZ31B in alkaline environments

Shengxi Li, Ana C. Bacco, Nick Birbilis, Hongbo Cong^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

42 Citations (Scopus)

Abstract

The passivation and corrosion behaviors of Mg alloy AZ31B were investigated in chloride-free NaOH solutions with pH range from 10 to 14. The results indicate that various phases behave differently at different pH levels. Al-Mn intermetallics serve as strong cathode at pH ≤ 11, but dissolve at pH ≥ 13. Ambient oxygen is responsible for the potential rise at pH ≥ 13 and subsequent significant potential oscillation (>1 V) is attributed to the passive film breakdown at the intergranular boundaries in the oxide film. Optimal passivation is achieved at pH 12 with thin uniform passive film formed across the surface.

Original language	English
Pages (from-to)	596-610
Number of pages	15
Journal	Corrosion Science
Volume	112
DOIs	https://doi.org/10.1016/j.corsci.2016.08.022
Publication status	Published - 1 Nov 2016
Externally published	Yes

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10.1016/j.corsci.2016.08.022

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title = "Passivation and potential fluctuation of Mg alloy AZ31B in alkaline environments",

abstract = "The passivation and corrosion behaviors of Mg alloy AZ31B were investigated in chloride-free NaOH solutions with pH range from 10 to 14. The results indicate that various phases behave differently at different pH levels. Al-Mn intermetallics serve as strong cathode at pH ≤ 11, but dissolve at pH ≥ 13. Ambient oxygen is responsible for the potential rise at pH ≥ 13 and subsequent significant potential oscillation (>1 V) is attributed to the passive film breakdown at the intergranular boundaries in the oxide film. Optimal passivation is achieved at pH 12 with thin uniform passive film formed across the surface.",

keywords = "A: Magnesium, B: Polarization, C: Alkaline corrosion, C: Oxygen reduction, C: Passive films, C: Pitting corrosion",

author = "Shengxi Li and Bacco, {Ana C.} and Nick Birbilis and Hongbo Cong",

note = "Publisher Copyright: {\textcopyright} 2016 Elsevier Ltd",

year = "2016",

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doi = "10.1016/j.corsci.2016.08.022",

language = "English",

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T1 - Passivation and potential fluctuation of Mg alloy AZ31B in alkaline environments

AU - Li, Shengxi

AU - Bacco, Ana C.

AU - Birbilis, Nick

AU - Cong, Hongbo

PY - 2016/11/1

Y1 - 2016/11/1

N2 - The passivation and corrosion behaviors of Mg alloy AZ31B were investigated in chloride-free NaOH solutions with pH range from 10 to 14. The results indicate that various phases behave differently at different pH levels. Al-Mn intermetallics serve as strong cathode at pH ≤ 11, but dissolve at pH ≥ 13. Ambient oxygen is responsible for the potential rise at pH ≥ 13 and subsequent significant potential oscillation (>1 V) is attributed to the passive film breakdown at the intergranular boundaries in the oxide film. Optimal passivation is achieved at pH 12 with thin uniform passive film formed across the surface.

AB - The passivation and corrosion behaviors of Mg alloy AZ31B were investigated in chloride-free NaOH solutions with pH range from 10 to 14. The results indicate that various phases behave differently at different pH levels. Al-Mn intermetallics serve as strong cathode at pH ≤ 11, but dissolve at pH ≥ 13. Ambient oxygen is responsible for the potential rise at pH ≥ 13 and subsequent significant potential oscillation (>1 V) is attributed to the passive film breakdown at the intergranular boundaries in the oxide film. Optimal passivation is achieved at pH 12 with thin uniform passive film formed across the surface.

KW - A: Magnesium

KW - B: Polarization

KW - C: Alkaline corrosion

KW - C: Oxygen reduction

KW - C: Passive films

KW - C: Pitting corrosion

UR - http://www.scopus.com/inward/record.url?scp=84994885378&partnerID=8YFLogxK

U2 - 10.1016/j.corsci.2016.08.022

DO - 10.1016/j.corsci.2016.08.022

M3 - Article

SN - 0010-938X

VL - 112

SP - 596

EP - 610

JO - Corrosion Science

JF - Corrosion Science

ER -

Passivation and potential fluctuation of Mg alloy AZ31B in alkaline environments

Abstract

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