Synthesis and characterization of nanocrystalline CrFeCoNi alloy by high energetic mechanical alloying

Semen’ko, M. P.; Ostapenko, R.V.; Teselko, Petro

doi:10.1109/nap.2017.8190394

Cited by 3 publications

(5 citation statements)

References 20 publications

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“…27 Due to the heterogeneous nature, a range of lattice spacing measurements were recorded mostly falling within the 0.20−0.25 nm range. The 0.25 nm lattice measurement shown within the HRTEM inset in Figure 3 falls within normal lattice spacing range for FCC FeCoNi alloys 40 and FCC CrFeCoNi alloys 41 for the (111) plane both before and after HER−OER catalytic testing. As observed in the XRD pattern, the 2θ shifts resemble the FCC CrFeCoNi alloy 41 more closely (Figure S8c).…”

Section: ■ Results and Discussionsupporting

confidence: 54%

“…The 0.25 nm lattice measurement shown within the HRTEM inset in Figure 3 falls within normal lattice spacing range for FCC FeCoNi alloys 40 and FCC CrFeCoNi alloys 41 for the (111) plane both before and after HER−OER catalytic testing. As observed in the XRD pattern, the 2θ shifts resemble the FCC CrFeCoNi alloy 41 more closely (Figure S8c). The XRD pattern does not change significantly after catalytic testing of HER and OER (Figure S8c).…”

Section: ■ Results and Discussionsupporting

confidence: 54%

“…XRD of the annealed 400 °C sample compared to the nonannealed sample (Figure S9a) showed the appearance of crystalline metal oxide signatures (both spinel Fe 42 and Co oxides, 43 and SnO 2 44 from the FTO glass substrate) along with the FCC metal. 40,41 We used whole pattern fitting with third polynomial background modeling to try to determine the composition of the spinel oxide peaks; however, due to the significant overlap of these signals as they are in the same phase as well as the strain caused by multiple species existing in the structure, the model was not able to make an accurate prediction as shown by the high R/E value of 1.79 of the pattern fitting (Figure S9b). We found that annealing catalyst 1 has minor impact on OER overpotential, but a significant impact on increasing HER overpotential (Figure S9c).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Direct Laser Writing of Multimetal Bifunctional Catalysts for Overall Water Splitting

McGee

Fest

Chandler

et al. 2023

ACS Appl. Energy Mater.

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Water electrolysis is of interest as a sustainable way to produce clean hydrogen and oxygen fuel and help mitigate the rising problems of climate change while meeting global energy demands. High-efficiency, stable, and earth-abundant bifunctional catalysts are needed to enable more effective electrochemical cells for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Here, we investigate the synthesis, composition, performance, and mechanism of multimetal catalysts serving dual functionality in both OER and HER of water electrolysis. Through a laser synthesis method, we synthesized heterogeneous catalysts of nanocrystalline multimetallic alloy pockets embedded within an amorphous oxide matrix. We evaluated the performance and composition of a range of mixed transition-metal oxide materials for both OER and HER, ultimately synthesizing a Cr0.01Fe0.27Co0.34Ni0.38O x /C y catalyst that has a stable, high-rate, and competitive overall water splitting performance of 1.76 V at 100 mA cm–2 in an alkaline medium. Using density functional theory to gain insight as the active site and mechanism, we propose that the inclusion of a minor amount of Cr increases the degeneracy of energetic states that lowers the cost of forming the O 2 p–d bond and H 1 s–d bond due to the hybridization of s, p, and d orbitals from Cr. Using a two-electrode water electrolysis cell with a constant potential of 1.636 V to mimic the setup for fuel production, we found the catalyst to be stable at 14–15 mA cm–2 for 40 h. This laser synthesis method allowing for facile and rapid synthesis of complex multimetal systems demonstrates how doping a Fe, Co, and Ni heterogeneous amorphous/nanocrystalline structure with small amounts of Cr is important for bifunctional catalytic behavior, particularly for increasing HER functionality in advancing our understanding for future electrocatalytic design.

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Section: ■ Results and Discussionsupporting

confidence: 54%

Section: ■ Results and Discussionsupporting

confidence: 54%

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Direct Laser Writing of Multimetal Bifunctional Catalysts for Overall Water Splitting

McGee

Fest

Chandler

et al. 2023

ACS Appl. Energy Mater.

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show abstract

“…They observed that the ideal crystallite size was achieved at 300 RPM when the RPM was controlled between 200 and 300. Khailo et al [126] pioneered the notion of high-intensity MA in the synthesis of HEAs. A single-phase FCC CoCrNiFe HEAs is developed in 2 h, whereas typical milling takes about 10 h. According to Salemi et al [127], suitable alloying was not accomplished after 50 h of milling time & a rotating speed of 300 RPM.…”

Section: Rotational Speedmentioning

confidence: 99%

A critical review on mechanically alloyed high entropy alloys: processing challenges and properties

Kumar

Singh

Suhane

2022

Mater. Res. Express

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High entropy alloys (HEAs) earned the attention of the scientific community since their discovery in the year 2004, while the progress in this field has been realized since the year 2010 when a drastic increase in demand for HEAs was observed due to their unique characteristics and ability to form several compositions. As universally acknowledged, the immense potential in compositions, microstructures, and properties has sparked a great interest in this field. Researchers primarily focused on equiatomic HEAs, but the paradigm eventually shifted to non-equiatomic alloys. As the research progressed, four core effects were identified as the most important aspects in enabling the distinct characteristics. Mechanical alloying (MA), followed by the sintering approach, has piqued the interest of all researchers focusing on HEA processing. Accordingly, the main objective of this review is to critically discuss mechanically alloyed HEAs in the view of mechanical properties, tribological behavior, and functional properties. Furthermore, the predominant challenges and their conceivable prospects are also deliberated that offer novelty to this review article.

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“…Furthermore, several of the unary, binary, and ternary alloys from these elements have important properties and are in widespread use. Among the quaternary or "medium entropy alloy" systems, CoCrFeNi is of interest because it can form a single-phase fcc solid solution with phase stability to at least medium temperatures [17,18]. While CoCrFeNi has interesting deformation behavior at high strain [19,20], it was selected here mainly because it is a MPEA with a widely applicable basis for achieving tailored properties by adjusting the concentrations of the constituent elements [21] or by adding others, such as in Mn, Al, Cu, Ti, etc.…”

Section: Introductionmentioning

confidence: 99%

Structure Zone Investigation of Multiple Principle Element Alloy Thin Films as Optimization for Nanoindentation Measurements

et al. 2020

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Multiple principal element alloys, also often referred to as compositionally complex alloys or high entropy alloys, present extreme challenges to characterize. They show a vast, multidimensional composition space that merits detailed investigation and optimization to identify compositions and to map the composition ranges where useful properties are maintained. Combinatorial thin film material libraries are a cost-effective and efficient way to create directly comparable, controlled composition variations. Characterizing them comes with its own challenges, including the need for high-speed, automated measurements of dozens to hundreds or more compositions to be screened. By selecting an appropriate thin film morphology through predictable control of critical deposition parameters, representative measured values can be obtained with less scatter, i.e., requiring fewer measurement repetitions for each particular composition. In the present study, equiatomic CoCrFeNi was grown by magnetron sputtering in different locations in the structure zone diagram applied to multinary element alloys, followed by microstructural and morphological characterizations. Increasing the energy input to the deposition process by increased temperature and adding high-power impulse magnetron sputtering (HiPIMS) plasma generators led to denser, more homogeneous morphologies with smoother surfaces until recrystallization and grain boundary grooving began. Growth at 300 °C, even without the extra particle energy input of HiPIMS generators, led to consistently repeatable nanoindentation load–displacement curves and the resulting hardness and Young’s modulus values.

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Synthesis and characterization of nanocrystalline CrFeCoNi alloy by high energetic mechanical alloying

Cited by 3 publications

References 20 publications

Direct Laser Writing of Multimetal Bifunctional Catalysts for Overall Water Splitting

Direct Laser Writing of Multimetal Bifunctional Catalysts for Overall Water Splitting

A critical review on mechanically alloyed high entropy alloys: processing challenges and properties

Structure Zone Investigation of Multiple Principle Element Alloy Thin Films as Optimization for Nanoindentation Measurements

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