Change in Oxygen Reduction Reactivity of Intermetallics: A Mechanism of the Difference in Trenching around Al–Fe and Al–Fe–Si Particles on AA1050 in NaCl

Kakinuma, Hiroshi; Muto, Izumi; Oya, Yoshiyuki; Momii, Takahiro; Jin, Ying; Sugawara, Yu; Hara, Nobuyoshi

doi:10.1149/1945-7111/acb6ba

Cited by 5 publications

(3 citation statements)

References 35 publications

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“…In general, the Cu accumulation results in a pronounced galvanic action, where the particles are the cathodes and the alloy matrix is the anode, and shallow trenches were reported to be generated around IMPs. 26,27,56,57 But, the trench shown in Fig. 12h was narrow and deep.…”

Section: Discussionmentioning

confidence: 96%

“…Intermetallic particles (IMPs) act as initiation sites for pitting. 23,[25][26][27] Guillaumin and Mankowski 28 studied the relationship among IMPs, pitting, and intergranular corrosion. They concluded that coarse IMPs are initiation sites for pits, which led to microscopic crystallographic tunnels, some of which penetrate grain boundaries, initiating intergranular corrosion.…”

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confidence: 99%

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Difference in the Precursory Process of the Intergranular Corrosion of Aged Al-Cu and Al-Cu-Mg Alloys in 0.1 M NaCl

Yoshida,

Nishimoto,

Muto

et al. 2023

J. Electrochem. Soc.

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Real-time in situ optical microscopy observations of the initiation behavior of intergranular corrosion on artificially aged Al-4.5Cu and Al-4.5Cu-1.5Mg were performed in naturally aerated 0.1 M NaCl at pH 6.0. For both alloys, the discoloration of intermetallic particles occurred before intergranular corrosion, and a discolored coarse intermetallic particle on the grain boundary acted as the initiation site for intergranular corrosion (Al2Cu for Al-4.5Cu and Al2CuMg for Al-4.5Cu-1.4Mg). The discoloration of Al2Cu particles was localized and occurred only on a small number of particles. However, almost all Al2CuMg particles were discolored; the overall surface of the particles was discolored uniformly. The discoloration of Al2Cu on Al-4.5Cu led to micropitting. In contrast, the discoloration of Al2CuMg on Al-4.5Cu-1.5Mg caused the trenching of particles. The difference in the initiation behavior of intergranular corrosion was discussed in terms of these precursory phenomena.

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Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

Difference in the Precursory Process of the Intergranular Corrosion of Aged Al-Cu and Al-Cu-Mg Alloys in 0.1 M NaCl

Yoshida,

Nishimoto,

Muto

et al. 2023

J. Electrochem. Soc.

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“…Kakinuma et almeasured the open-circuit potentials of the bulk intermetallic compounds and Al-matrix of AA1050 without intermetallic particles. The cathodic reactivity on bulk Al-Fe was higher than that on bulk Al-Fe-Si under aspolished condition [26]. The rich iron content in the aluminum matrix greatly influences the coating's corrosion resistance and electrochemical properties.…”

Section: Introductionmentioning

confidence: 95%

Effect of Si Content on Microstructures and Electrochemical Properties of Al-xSi-3.5Fe Coating Alloy

Wu,

Shen,

Wang

et al. 2023

Materials

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Hot-dip aluminum alloy is widely used in the engineering fields. However, during the aluminum plating process, Fe inevitably enters and reaches a saturation state, which has a significant impact on the corrosion resistance and microstructure of the coating. Currently, adding Si during the hot-dip aluminum process can effectively improve the quality of the coating and inhibit the Fe-Al reaction. To understand the effect of Si content on the microstructure and electrochemical performance of Al-xSi-3.5Fe coating alloys, the microstructure and post-corrosion morphology of the alloys were analyzed using SEM (Scanning Electron Microscope) and XRD (X-ray Diffraction). Through electrochemical tests and complete immersion corrosion experiments, the corrosion resistance of the coating alloys in 3.5 wt.% NaCl was tested and analyzed. The results show that the Al-3.5Fe coating alloy mainly comprises α-Al, Al3Fe, and Al6Fe. With the increase in Si addition, the iron-rich phase changes from Al3Fe and Al6Fe to Al8Fe2Si. When the Si content reaches 4 wt.%, the iron-rich phase is Al9Fe2Si2, and the excess Si forms the eutectic Si phase with the aluminum matrix. Through SKPFM (Scanning Kelvin Probe Force Microscopy) testing, it was determined that the electrode potentials of the alloy phases Al3Fe, Al6Fe, Al8Fe2Si, Al9Fe2Si2, and eutectic Si phase were higher than that of α-Al, acting as cathode phases to the micro-galvanic cell with the aluminum matrix, and the corrosion form of alloys was mainly galvanic corrosion. With the addition of silicon, the electrode potential of the alloy increased first and then decreased, and the corrosion resistance results were synchronous with it. When the Si content is 10 wt.%, the alloy has the lowest electrode potential and the highest electrochemical activity.

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Elucidation of the trigger for trenching around Al6(Fe, Mn) on AA5083 aluminum alloy in diluted synthetic seawater

Kosaba,

Nishimoto,

Muto

2024

Corrosion Science

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Change in Oxygen Reduction Reactivity of Intermetallics: A Mechanism of the Difference in Trenching around Al–Fe and Al–Fe–Si Particles on AA1050 in NaCl

Cited by 5 publications

References 35 publications

Difference in the Precursory Process of the Intergranular Corrosion of Aged Al-Cu and Al-Cu-Mg Alloys in 0.1 M NaCl

Difference in the Precursory Process of the Intergranular Corrosion of Aged Al-Cu and Al-Cu-Mg Alloys in 0.1 M NaCl

Effect of Si Content on Microstructures and Electrochemical Properties of Al-xSi-3.5Fe Coating Alloy

Elucidation of the trigger for trenching around Al6(Fe, Mn) on AA5083 aluminum alloy in diluted synthetic seawater

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