Faraday Discussions最新文献

Few areas of materials science have evolved as rapidly and dynamically as high-entropy alloys (HEAs). What began just two decades ago as a bold idea - first articulated by Brian Cantor and Jien-Wei Yeh - that chemical complexity itself could stabilise materials, has grown into a thriving research field spanning structural, functional, and catalytic applications. The Faraday Discussions 'High-entropy alloy nanostructures: from theory to application', held at the Royal Society of Chemistry in London, brought together researchers from across the world to examine a fundamental question at the heart of this concept: with multicomponent alloys now within reach, do they truly deliver beyond simpler systems, or does complexity risk obscuring purpose?

The nanoscale distribution of elements in two multi-component materials is assessed by unsupervised machine learning methods. These are compared to elemental maps to highlight the potential shortcomings of simplistic compositional analyses. Quantification of the resulting microstructure components provides insight into the evolution of the microstructure and the possible reasons for misinterpretation of the traditional element maps.

High-entropy alloys (HEAs) combine five or more elements in near-equiatomic ratios, opening an immense compositional space whose optical behaviour is still largely unknown. Phase-modulated ellipsometry on bulk CrMnFeCoNi (Cantor) shows that its intrinsic optical constants, n, k, ε₁ and ε₂, deviate strongly from the arithmetic means of the constituent elements-by up to a factor of two beyond 1 μm-yet the derived functional responses, reflectance R and absorption coefficient α, are reproduced to within ∼20%. Cantor nanoparticles have been produced by nanosecond electric discharges in liquid nitrogen. Dark-field spectroscopy and Mie calculations reveal a dominant scattering mode near 100 nm that red-shifts and broadens with increasing size; the steady-state photothermal rise calculated from the absorption cross-section σ_abs falls between those of the constituent pure metals. Generalising the averaging rule, we compute proxy values of R and α for 10 994 density-functional-theory-predicted HEAs. Successive optical, thermal and resource filters condense the space to 58 candidates at 355 nm and eight refractory alloys at 1064 nm, illustrating a "sustainable-by-design" route for future HEA photonics.

High entropy alloys (HEAs) have gained significant attention in materials science and engineering due to their stable phases. These alloys are made up of five or more major elements in equimolar or near-equimolar proportions, enabling them to harness the properties of multiple elements rather than depending on a single one. In this study, nanocrystalline FeCoCuNbMo high-entropy alloy powders were synthesised via the mechanical alloying method with high-energy SPEX ball milling. The microstructures and crystal properties of the milled powders at regular intervals of milling were investigated through X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). XRD analysis revealed the BCC phase formation after 20 hours of milling. A study of diffraction patterns was conducted to find out the average crystallite size and internal strains, utilising Scherrer's formula and Williamson-Hall analysis, based on a uniform deformation model. Additionally, changes in particle size as a function of milling time were studied using nano zeta potential analysis. As milling time increased, the crystallite sizes decreased due to dislocations and stacking faults in the crystals, and nano-crystalline structure formations were observed after 20 h of milling.

High-throughput synthesis of multi-element alloy nanoparticles (MEA NPs) is essential for accelerating the discovery of advanced materials with complex compositions. Herein, we developed an automated continuous-flow reactor system capable of synthesising a wide variety of MEA NPs under controlled solvothermal conditions (up to 400 °C and 35 MPa). The system demonstrates a high screening throughput, capable of preparing up to 20 distinct samples in a single, automated run, with each synthesis requiring only 30 minutes. A key throughput optimising feature is the parallel process execution, whereby precursor preparation and system cleaning are performed concurrently via the reactor heating, synthesis, and cooling cycles. All washing procedures, for both the precursor preparation module and reactor unit, are fully automated, further minimising downtime. We demonstrated its versatility by successfully synthesising a wide range of MEA NPs, including high-entropy alloys, composed of various combinations of d- and p-block metals. The synthesized materials, ranging from bimetallic RuPd to ten-element CoNiCuRuRhPdInSnIrPt alloys, were all crystalline, single-phase face-centred cubic solid solutions. Furthermore, the platform enables the direct one-step synthesis of supported MEA catalysts, such as RuRhPdIrPt/CeO₂. For this supported catalyst, we achieved a practical mass throughput with a theoretical production rate of 0.5 g h^-1 for the MEA NPs (corresponding to 27 g h^-1 for the total catalyst including the support). The final product yield was approximately 56% under the current protocol, which is designed to prevent cross-contamination by automatically discarding the initial and final portions of the product slurry. We anticipate this yield can be readily improved in a system configuration optimized for mass throughput rather than for high-throughput screening. This study presents a scalable and versatile system for high-throughput MEA NPs synthesis and offers a practical solution for bridging the gap between computational predictions and experimental materials development.