Corrosion Resistance Behavior of Mg-Zn-Ce/MWCNT Magnesium Nanocomposites Synthesized by Ultrasonication-Assisted Hybrid Stir–Squeeze Casting for Sacrificial Anode Applications

The influence of multiwall carbon nanotube (MWCNT) reinforcements on electrochemical corrosion investigations at varying NaCl concentrations (0.4 M, 0.6 M, 0.8 M, 1 M) of Mg-Zn-Ce nanocomposites is studied in this work. The Mg-Zn-Ce/MWCNT nanocomposites were developed by using an ultrasonication-ass...

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Main Authors: S. C. Amith, Poovazhagan Lakshmanan, Gnanavelbabu Annamalai, Manoj Gupta, Arunkumar Thirugnanasambandam
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/6/673
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Summary:The influence of multiwall carbon nanotube (MWCNT) reinforcements on electrochemical corrosion investigations at varying NaCl concentrations (0.4 M, 0.6 M, 0.8 M, 1 M) of Mg-Zn-Ce nanocomposites is studied in this work. The Mg-Zn-Ce/MWCNT nanocomposites were developed by using an ultrasonication-assisted hybrid stir–squeeze (UHSS) casting method with different MWCNT concentrations (0, 0.4, 0.8, 1.2 wt.%) in a Mg-Zn-Ce magnesium alloy matrix. The microstructural characterizations shown using X-ray diffraction revealed the presence of secondary phases (MgZn<sub>2</sub>, Mg<sub>12</sub>Ce), T-phase (Mg<sub>7</sub>Zn<sub>3</sub>RE), α-Mg, and MWCNT peaks. Optical microscopy results showed grain refinement in the case of nanocomposites. Transmission electron microscope studies revealed well-dispersed MWCNT, indicating the good selection of processing parameters. The uniform dispersion of MWCNTs was achieved due to a hybrid stirring mechanism along with transient cavitation, ultrasonic streaming, and squeeze effect. The higher E<sub>corr</sub> value of −1.39 V, lower I<sub>corr</sub> value (5.81 µA/cm<sup>2</sup>), and lower corrosion rate of 0.1 mm/Yr (↑77%) were obtained by 0.8% nanocomposite at 0.4 M NaCl concentration, when compared to the monolithic alloy. The Mg(OH)<sub>2</sub> passive film formation on 0.8 wt.% nanocomposite was denser, attributed to the refined grains. At higher NaCl concentration, the one-dimensional morphological advantage of MWCNT helped to act as a barrier for further Mg exposure to excessive Cl<sup>−</sup> attack, which reduced the formation of MgCl<sub>2</sub>. Therefore, the UHSS-casted Mg-Zn-Ce/MWCNT nanocomposites present a good potential as sacrificial anodes for use in a wide range of industrial applications.
ISSN:2075-4701