Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders
Transition metal based high entropy alloys (HEAs) are often used in electrocatalytic (water electrolysis) applications due to the synergistic effect operating among its constituent elements and unpaired electrons in d orbitals of the concerned metal. In this study, a low cost NiMnFeCu high entropy a...
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MDPI AG
2022-01-01
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| author | Ashok Kumar Michael Mucalo Leandro Bolzoni Yiming Li Fantao Kong Fei Yang |
| author_facet | Ashok Kumar Michael Mucalo Leandro Bolzoni Yiming Li Fantao Kong Fei Yang |
| author_sort | Ashok Kumar |
| collection | DOAJ |
| description | Transition metal based high entropy alloys (HEAs) are often used in electrocatalytic (water electrolysis) applications due to the synergistic effect operating among its constituent elements and unpaired electrons in d orbitals of the concerned metal. In this study, a low cost NiMnFeCu high entropy alloy was successfully synthesised using the combined techniques of mechanical milling (MA) and vacuum sintering. X-ray diffraction was used to analyse the phase composition, optical microscopy, and scanning electron microscopy were used to characterise the fabricated material’s microstructure and chemical homogeneity, thermal, and mechanical properties were tested using the differential scanning calorimetry method and a universal testing machine, respectively. Electrochemical workstation was used to carry out preliminary electrochemical studies such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and chronoamperometry. The results showed that the as- sintered NiMnFeCu HEA possessed a single- phase FCC structure. The HEA NiMnFeCu sintered at 1050 °C (S4) and 1000 °C (S2) with a holding time of 2 h showed a yield strength of 516.3 MPa and 389.8 MPa, respectively, and the micro-hardness values were measured to be 233.45 ± 9 HV and 198.7 ± 8 HV, respectively. Preliminary electrochemical studies proved that the alloy sintered at 1000 °C (S2) with a holding time of 2 h exhibited excellent electrocatalytic properties with a measured overpotential of 322 mV at 10 mA cm<sup>−2</sup> at 100 cycles of CV and good stability for 10 h when compared to state-of-the-art electrocatalytic materials <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>IrO</mi></mrow><mn>2</mn></msub></mrow></semantics></math></inline-formula> and Ru<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula>. This suggested that the HEA NiMnFeCu fabricated under the condition S2 could potentially be used for industrial-scale water electrolysis as it possesses permissible mechanical and good electrochemical properties. |
| first_indexed | 2024-03-10T00:56:17Z |
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| spelling | doaj.art-f034299fd62b4258b70e0af9a54001a22023-11-23T14:43:21ZengMDPI AGMetals2075-47012022-01-0112116710.3390/met12010167Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental PowdersAshok Kumar0Michael Mucalo1Leandro Bolzoni2Yiming Li3Fantao Kong4Fei Yang5Waikato Centre for Advanced Materials and Manufacturing, School of Engineering, University of Waikato, Hamilton 3240, New ZealandSchool of Science, University of Waikato, Hamilton 3240, New ZealandWaikato Centre for Advanced Materials and Manufacturing, School of Engineering, University of Waikato, Hamilton 3240, New ZealandKey Laboratory of Advanced Metals and Materials of Inner Mongolia, School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, ChinaSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaWaikato Centre for Advanced Materials and Manufacturing, School of Engineering, University of Waikato, Hamilton 3240, New ZealandTransition metal based high entropy alloys (HEAs) are often used in electrocatalytic (water electrolysis) applications due to the synergistic effect operating among its constituent elements and unpaired electrons in d orbitals of the concerned metal. In this study, a low cost NiMnFeCu high entropy alloy was successfully synthesised using the combined techniques of mechanical milling (MA) and vacuum sintering. X-ray diffraction was used to analyse the phase composition, optical microscopy, and scanning electron microscopy were used to characterise the fabricated material’s microstructure and chemical homogeneity, thermal, and mechanical properties were tested using the differential scanning calorimetry method and a universal testing machine, respectively. Electrochemical workstation was used to carry out preliminary electrochemical studies such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and chronoamperometry. The results showed that the as- sintered NiMnFeCu HEA possessed a single- phase FCC structure. The HEA NiMnFeCu sintered at 1050 °C (S4) and 1000 °C (S2) with a holding time of 2 h showed a yield strength of 516.3 MPa and 389.8 MPa, respectively, and the micro-hardness values were measured to be 233.45 ± 9 HV and 198.7 ± 8 HV, respectively. Preliminary electrochemical studies proved that the alloy sintered at 1000 °C (S2) with a holding time of 2 h exhibited excellent electrocatalytic properties with a measured overpotential of 322 mV at 10 mA cm<sup>−2</sup> at 100 cycles of CV and good stability for 10 h when compared to state-of-the-art electrocatalytic materials <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>IrO</mi></mrow><mn>2</mn></msub></mrow></semantics></math></inline-formula> and Ru<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula>. This suggested that the HEA NiMnFeCu fabricated under the condition S2 could potentially be used for industrial-scale water electrolysis as it possesses permissible mechanical and good electrochemical properties.https://www.mdpi.com/2075-4701/12/1/167high entropy alloyspowder metallurgyvacuum sinteringmicrostructureoxygen evolution reaction |
| spellingShingle | Ashok Kumar Michael Mucalo Leandro Bolzoni Yiming Li Fantao Kong Fei Yang Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders Metals high entropy alloys powder metallurgy vacuum sintering microstructure oxygen evolution reaction |
| title | Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders |
| title_full | Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders |
| title_fullStr | Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders |
| title_full_unstemmed | Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders |
| title_short | Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders |
| title_sort | fabrication microstructure mechanical and electrochemical properties of nimnfecu high entropy alloy from elemental powders |
| topic | high entropy alloys powder metallurgy vacuum sintering microstructure oxygen evolution reaction |
| url | https://www.mdpi.com/2075-4701/12/1/167 |
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