In-situ Mg2+ release monitored during magnesium alloy corrosion

• Fabrication and analytical validation of a micro Mg2+ potentiometric sensor.
• In-situ electrochemical detection of Mg2+ ions generated from a corroding Mg alloy.
• Pre-positioning of micro Mg2+ sensor with high resolution using shear force mode.
• Correlation of Al and microstructure distribution in Mg alloys with Mg2+ release.
• Precise determination of Mg(OH)2 precipitation time.

Quantitative in-situ and localized analytical methods that can monitor Mg2+ release are central to probe the impact of the microstructure on magnesium alloy corrosion. As such, a potentiometric micro-Mg2+ ion-selective membrane electrode is fabricated, calibrated, characterized and used to selectively monitor the Mg2+ release from different cast Mg AM50 alloys during corrosion. We demonstrate that the local Mg2+ release is tied to the alloy microstructure and its aluminum distribution, indicating a possibility of optimization of the base material corrosion properties.

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