Abstract
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−2 at 100 cycles of CV and good stability for 10 h when compared to state-of-the-art electrocatalytic materials IrO2 and RuO2. 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.
Highlights
Introduction iationsHigh entropy alloys (HEAs) are a new paradigm in designing alloys that have gained significant research interest in the last decade
We report a cobalt free, cheap NiMnFeCu high entropy alloys (HEAs) fabricated by combined mechanical alloying and vacuum sintering techniques, which is intended for electrocatalytic applications
There are several factors that contribute to the phase formation in HEAs [32]
Summary
Introduction iationsHigh entropy alloys (HEAs) are a new paradigm in designing alloys that have gained significant research interest in the last decade. HEAs have very attractive properties that cannot be seen in conventional alloys, such as high strength and hardness [4,5,6,7,8,9,10], excellent wear-resistance [11,12,13], good fatigue and toughness [14,15,16], as well as good corrosion and oxidation resistance [17] They show good mechanical properties from room temperature to even cryogenic temperatures [18]. These unique properties are attributed to the four core effects present in HEAs, namely the high entropy effect, the sluggish diffusion effect, the lattice distortion effect, and the cocktail effect [2]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
