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Design, structure/Microstructure Evolution, Mechanical and Corrosion properties of Two New pseudo-High Entropy Amorphous Alloys

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ssRN 2023年

作者： Batalha, Weverson Capute Roche, Virginie Champion, Yannick Mantel, Marc Verdier, Marc Martin, Vincent Kiminami, Claudio s. Junior, Alberto M.J. Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS Grenoble INP LEPMI Grenoble38000 France Univ. Grenoble Alpes CNRS Grenoble INP SIMAP Grenoble38000 France Graduate Program of Materials Science and Engineering Federal University of São Carlos Dema São Carlos13565-905 Brazil

The influence of devitrification on structure/microstructure, corrosion, and mechanical properties of two new FeCrMoNbB and FeCrMoNiB pseudo-high entropy (pHE) amorphous alloys have been investigated to be used as coatings possibly. specimens were characterized using several techniques. Amorphous ribbons produced by melt spinning were heat-treated to simulate crystallization, which may occur during coating processing. As pHE alloys, amounts of amorphous phases were kept at high temperatures and crystallized in multi-principal element (MpE) bcc or fcc phases, with few borides. A 500 μm thick physically simulated coatings of commercial-grade precursors using spray forming in the air were produced to infer their viability and glass-forming ability and confirm the crystallization path and mechanical properties. The coating of the Nb-pHE alloy was nearly amorphous, and the Ni-pHE one crystallized in phases of ribbons treated at 1000 °C with fewer borides. Nanoindentation evaluated the ribbons' mechanical behavior and coatings by Vickers microhardness. Ribbons' hardness and elastic modulus depended on annealing temperatures and were very high, indicating high wear resistance. Hardness values were confirmed by the simulated coatings. Corrosion properties evaluated by potentiodynamic polarization in seawater at different pHs showed outstanding corrosion resistance in amorphous conditions. After devitrification, both compositions preserved excellent corrosion behavior up to ~700 °C. However, the Nb-pHE alloy corrosion resistance was better than the Ni-pHE alloy. pitting corrosion was not present in any condition. Even after crystallization, resistance to corrosion and wear indicates that these materials are promising for coating applications through different techniques. © 2023, The Authors. All rights reserved.

关键词： Entropy

Flexible Copper‑Doped silica Fibers promote Infected Conjunctival Tissue Repair Through Antibacterial and Anti‑inflammatory Effects

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Advanced Fiber materials 2024年第1期6卷 278-296页

作者： Jie Cui Yuchen Cai Xiao Yu Yihong shen Tianyi Zhou Binbin sun pengfei Cai Zhengchao Yuan Muhammad shafiq Mohamed EL‑Newehy Hany EL‑Hamshary Xingping Zhou Yao Fu Xiumei Mo State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Shanghai Engineering Research Center of Nano‑Biomaterials and Regenerative MedicineCollege of Biological Science and Medical EngineeringDonghua UniversityShanghai 201620People’s Republic of China Department of Ophthalmology Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011People’s Republic of China Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology Shanghai 200011People’s Republic of China Innovation Center of NanoMedicine Kawasaki Institute of Industrial Promotion3‑25‑14 Tono‑machiKawasaki‑kuKanagawa 210‑0821Japan United Graduate School of Drug Discovery and Medical Information Sciences Gifu University1‑1 YanagidoGifu 501‑1193Japan Department of Chemistry College of ScienceKing Saud UniversityP.O.Box 245511451 RiyadhSaudi Arabia

The conjunctiva is crucial in safeguarding the eye from harm or infection,thereby ensuring the preservation of the *** repair of infected conjunctival damage is *** objective of this study is to develop copper-doped flexible silica nanofibers(siO_(2)@Cu NFs)with multifunctional antibacterial and anti-inflammatory *** continuous release of copper ions from electrospun membranes is shown to be effective to promote antibacterial and bioactive *** membranes also exhibit biocompatibility and promote cell growth,angiogenesis,and inflammation *** vivo evaluations further reveal the therapeutic efficacy of siO_(2)@Cu NFs to promote the structural and the functional recoveries of the *** together,siO_(2)@Cu NFs may hold significant promise for the fabrication of alterna-tive ocular bandage to suppress bacterial infection and promote repair of ocular tissues and may potential be also used for related disciplines.

关键词： Conjunctival reconstruction Inorganic nanofiber Bacterial infection Angiogenesis Anti-inflammation

Theoretical insights into the chemical bonding, electronic structure, and spectroscopic properties of the lanarkite pb2sO5 structure

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arXiv

arXiv 2023年

作者： Fabris, Guilherme s.L. Ferrer, Mateus M. sambrano, Julio R. Almeida, Cláudio R.R. paskocimas, Carlos A. La porta, Felipe A. Graduate Program in Materials Science and Engineering Technological Development Center Universidade Federal de Pelotas RS Pelotas96010-610 Brazil Modeling and Molecular Simulation Group São Paulo State University Bauru São Paulo17033-360 Brazil Department of Materials Engineering Federal University of Rio Grande do Norte RN Natal59078-970 Brazil Postgraduate Program in Science and Engineering of Materials Federal University of Rio Grande do Norte RN Natal59078-970 Brazil Federal University of Technology - Paraná Nanotechnology and Computational Chemistry Laboratory Avenida dos Pioneiros 3131 CEP PR Londrina86036-370 Brazil State University of Londrina Post-Graduation Program in Chemistry Rodovia Celso Garcia Cid 445 km 380 CEP PR Londrina86057-970 Brazil

Lanarkite is a mineral formed by a combination of lead, sulphur, and oxygen atoms arranged in the general chemical formula pb2sO5 (psO) that crystallises with monoclinic symmetry (belonging to the C2/m space group, No. 12). This mineral was first discovered in Lanarkshire, scotland and was named after its location. psO has a unique structure comprising alternating penta-coordinated lead [pbO5] and tetra-coordinated sulphur [sO4] clusters. This lanarkite-type structure has recently attracted significant scientific interest and has been the focus of the superconducting material research community. However, its chemistry needs to be explored further. This article presents a comprehensive investigation on the chemical bonding, electronic structure, and spectroscopic properties of the lanarkite-type psO structure from a computational perspective. Thus, different functionals in the DFT (e.g., pBE, pBE0, pBEsOL, pBEsOL0, BLYp, WC1LYp37, and B3LYp) were assessed to accurately predict their fundamental properties. All the DFT calculations were performed using a triple-zeta valence plus polarisation basis set. Among all the DFT functionals tested in this study, pBE showed the best agreement with the experimental data available in the literature. Our results also reveal that the [pbO5] clusters are formed with three pb–O bond lengths, with values of about 2.32, 2.59, and 2.84 Å, respectively, while the [sO4] clusters have the same s–O bond length of 1.57 Å. We performed a complete topological analysis of this system to comprehend these structural differences. Additionally, the psO structure has an indirect band gap energy of 2.9 eV and an effective mass ratio (mℎ∗ /me∗) of about 0.415 (using pBE calculations) which may, in principle, indicate a low recombination of electron-hole pairs in the lanarkite structure. Therefore, we believe that a detailed understanding of their electronic structures, spectroscopic properties as well as their chemical bonding is critically important

关键词： Lead compounds

Advanced Under-Rails Fiber-Optic sensor for Detection of Rolling stock and Axles in Tram Transport

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IEEE Transactions on Instrumentation and Measurement 2025年 74卷

作者： Fajkus, Marcel Jargus, Jan Nedoma, Jan Kepak, stanislav Krizan, Daniel Cubik, Jakub Krenzelok, Tomas Leal, Arnaldo Marques, Carlos VSB—Technical University of Ostrava Faculty of Electrical Engineering and Computer Science Department of Telecommunications Ostrava708 00 Czech Republic Prodin a.s. Pardubice530 02 Czech Republic Graduate Program in Electrical Engineering Federal University of Espirito Santo Vitoria29075-910 Brazil University of Aveiro CICECO—Aveiro Institute of Materials Physics Department Aveiro3810-193 Portugal VSB—Technical University of Ostrava Department of Physics Ostrava708 00 Czech Republic

This article describes the implementation of an advanced fiber-optic intensity sensor for the comprehensive detection of axles and bogies of rail vehicles in tram transport. The sensor uses the principle of optical fiber bending, where the intensity of transmitted light is modulated due to mechanical stress on the fiber caused by the passage of a tram and the subsequent reversible deformation of the rail. The innovative design of the sensor allows for its easy installation under the rail foot, between the rail and the sleeper, replacing conventional anti-vibration pads, and includes specially designed deformable elements which the optical fiber bends and modulates the transmitted light intensity. During long-term testing (11 months in various weather conditions) conducted in the real tram depot (Ostrava, Czech Republic), 20602 tram passages were secured and analyzed. The sensor demonstrated success in detecting bogies, achieving 100% accuracy with no false positives (Fps) or false negatives (FNs). Axle detection showed an average success rate of 86.1%, with variability among different tram types up to 97.8%. The signal modulation was also subjected to detailed analysis, revealing differences in responses between various tram types, which can be attributed to differences in bogie construction and vehicle weight. Due to its electromagnetic immunity, the implemented fiber-optic sensor offers the potential for more reliable detection and broad application possibilities, including track occupancy monitoring, speed measurement, or determining the direction of travel on single-track lines. With slight optimization, the sensor could also be used to weigh rail vehicles or as an axle counter in railway or light rail transport. © 1963-2012 IEEE.

关键词： Bogies (railroad rolling stock)

Effect of Temperature and Mischmetal Addition on the Microstructure, Mechanical Andcorrosion Behavior of Crn Hard Coatings Deposited Onto Zk60 Magnesium Alloys Using Hipims

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ssRN 2023年

作者： pereira da silva, Erenilton Oliveira Junior, William Tavares Avila, pedro Renato Lima Ribeiro, Josy Kelly Alves dos santos, Marcos Junio Cortez Maciel, Natalia Mendes Rodrigues, Alisson pinto, Haroldo Cavalcanti MG Janaúba39447-790 Brazil Department of Engineering Physics Polytechnique Montréal P.O. Box 6079 Station Centre-Ville MontréalQCH3C 3A7 Canada Graduate Program in Materials Science UnB Planaltina Faculty University of Brasilia DF Brasilia70904-910 Brazil SP São Carlos13566-590 Brazil

Magnesium alloys have recently gained popularity due to their low density and suitability for various applications requiring both lightweight and robust mechanical qualities. Nevertheless, their widespread utilization could be improved by their inadequate corrosion resistance. This study examines the deposition of ceramic films using chromium nitride (CrN) via High power Impulse Magnetron sputtering (HipIMs) on ZK60 and ZK60 + 1.5 Mischmetal (MM) at 200°C and 300°C. The morphology and thickness of the CrN films was evaluated by Field Emission Gun-scanning Electron Microscopy (FEG-sEM) and X-ray Diffraction (XRD), roughness by atomic force microscopy (AFM), and mechanical properties (hardness and elastic modulus) were measured by nanoindentation experiments. Furthermore, the electrochemical impedance spectroscopy (EIs) analysis was used to evaluate the corrosion resistance. Fractured cross-section sEM-FEG images of CrN coatings deposited at 200°C and 300°C revealed differences in thickness and morphology for all samples. ZK60 samples exhibited thicker coatings compared to ZK60+1.5MM, which can be attributed to the stability of intermetallic phases. Increasing temperature resulted in the formation of thinner coatings. Also, at 300°C samples presented different thickness. surface roughness decreases with temperature, reflecting the formation of refined columnar structures. Hardness and elastic modulus increased with temperature, also presenting different behaviors at 300°C. Corrosion resistance also presented improvement at higher temperatures, with ZK60 outperforming ZK60+1.5MM, as EIs analysis confirmed the denser films enhance corrosion protection, while porous coatings exhibit lower resistance, as was observed for ZK60+1.5MM at 300°C. Results also showed the impact of the thermic stability of the samples on the coating formation, indicating that substrate temperature rises during deposition, leading to possible phase changes in the substrate and, consequently, affe

关键词： Corrosion resistance

Flake-like structure of srTiO3 nanoparticles dispersed on graphene oxide: A selective and sensitive electrochemical sensor for determination of chloramphenicol in milk and honey samples

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Food Chemistry 2024年 444卷

作者： sakaleshpur Kumar, Gagankumar Ballur prasanna, sanjay Lokesh Marenahalli, Bhuvan shadakshari, sandeep Arehalli shivamurthy, santhosh Rajabathar, Jothi Ramalingam Chimatahalli shanthakumar, Karthik Han, Young-Kyu Department of Chemistry SJCE JSS Science and Technology University Karnataka570006 India Department of Energy and Materials Engineering Dongguk University-Seoul Seoul100-715 Korea Republic of Taipei10608 Taiwan International PhD Program for Biomedical Engineering Taipei Medical University 250 Wuxing St Taipei11031 Taiwan N.M.K.R.V. College for Women's Karnataka 560011 India Department of Chemistry College of Science King Saud University P.O. Box. 2455 Riyadh11451 Saudi Arabia

The use of Chloramphenicol (CAp), a potent antibiotic with broad-spectrum capabilities in food-producing animals has been restricted by the European Union and several other countries due to its severe side effects. Thus, CAp must be detected quickly and sensitively. In this investigation, the preparation of srTiO3 nanoparticles was carried out utilizing a hydrothermal technique. The as-synthesized strontium titanate was decorated on the graphene oxide (srTiO3/GO) using an ultrasonication method. An electrochemical sensor was developed by employing a modified electrode consisting of srTiO3/GO, which can accurately detect CAp in food samples. The synergistic effect of srTiO3 and GO could improve the peak current response. Remarkably, the srTiO3/GO-modified glassy carbon electrode has a LOD and sensitivity of 6.08 µM nM and 2.771 µA·μM−1·cm−2, respectively. This modified electrode was evaluated in food samples and had an outstanding reaction with a high percentage of recovery, which makes it a potential electrocatalyst for CAp detection. © 2024 Elsevier Ltd

关键词： Titanium compounds

Magnetic and Electric Behavior of spike- and petal-Like Nanoscaled Cu:Zno superstructures Diluted Magnetic semiconductors

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ssRN 2022年

作者： Gunnewiek, Rodolfo Foster Klein perdomo, Claudia p.F. Almeida, Diógenes F. Cancellieri, Igor C. Garcia, Leonardo A. Cardoso, André L.F. Federal University of São Carlos Graduate Program in Materials Science and Engineering Rod. Washington Luiz km 235 SP São Carlos13565-905 Brazil Federal University of Alfenas Graduate Program in Materials Science and Engineering Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400 Brazil Federal University of Alfenas Institute of Science and Technology Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400 Brazil

Room temperature ferromagnetism (RTFM) is the main condition for searching for materials to be applied in spintronics. Beyond the candidates, the diluted magnetic semiconductors (DMs) are potential materials for such application. The introduction of a foreign transition metal ion in the semiconductor lattice may lead to the RTFM, where the intrinsic ferromagnetism developed by a nonmagnetic ion is preferable for spintronics application. In this work, single-phase Cu-substituted zinc oxide was synthesized by a fast polymeric precursor method, providing nanocrystallites from 4 to 11 nm. Copper hindered grain growth, even for high Cu concentrations. The crystallites assembled to superstructures with petal and spike-like morphologies, following an unconventional crystallization. The texturization observed during the crystallization led to the development of unexpected weak RTFM. The number of oxygen vacancies is too small to promote the RTFM since few atoms of copper find attached to the vacancies. probably the RTFM arises from overlapped spin-split bound magnetic polarons (BMp) due to the interaction of the hybridized O 2p and localized unoccupied twofold t2 subband of Cu 3d states. Although the sintering of pure and Cu-doped ZnO particles was equivalent, the electrical properties diverged. The copper insertion enhanced the resistivity and the non-linearity coefficient reached values higher than the unity. This is maybe due to the presence of copper at the grain boundaries forming a schottky barrier. Neither the non-ohmic electrical behavior nor the RTFM from nanostructured superstructures was ever reported before. © 2022, The Authors. All rights reserved.

关键词： II-VI semiconductors

Effects of MXenes (Ti3C2Tx) deposition by drop casting on the fretting wear of structural concrete

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Wear 2025年 570卷

作者： silva, Cristiane Arpino Gonçalves, Margarete R.F. Rosenkranz, Andreas Hammes, Gisele Costa, Henara Lillian Universidade Federal de Pelotas Materials Science and Engineering Graduate Program Rua Gomes Carneiro 1 Porto RS Pelotas Brazil University of Chile Department of Chemical Engineering Biotechnology and Materials Avenida Beauchef 851 Santiago Chile Universidade Federal de Santa Catarina LabMat Rua Delfino Conti s/n. Bloco B Trindade SC Florianópolis Brazil Universidade Federal do Rio Grande School of Engineering Av. Itália km 8 Bairro Carreiros RS Rio Grande Brazil

In civil engineering, concrete is the most widely used material due to the availability of its components. Research on tribology of semi-rigid structural systems is important in civil engineering, as the initially rigid contact between concrete and metallic elements can generate micromovement, resulting in wear due to fretting and possible cracks. Recently, a new family of 2D metal carbide and nitride nanosheets called MXenes has stood out in tribological applications due to their layered structure, which provides self-lubricating and reinforcing properties, but they are costly and difficult to produce in large scale, making their use in civil engineering challenging, despite encouraging results from the literature. To overcome this, the present work proposed surface deposition of MXenes by drop-casting (involving very small amounts of Mxenes) to control fretting wear between concrete and steel. One and five applications were deposited from a dispersion at a concentration of approximately 0.4 mg/mL of MXenes in isopropanol. Fretting tests were carried out on concrete (with and without MXenes deposition) against steel counterbodies for a total stroke of 200 μm under different speeds (0.2 and 2 mm/s) and times (5 and 30 min). The results showed that the friction coefficients obtained in the fretting tests did not present a statistically significant difference when using Mxenes either as a reinforcement in the concrete or deposited by drop casting. The wear rates obtained from the fretting tests demonstrated that, for the lower speed, no significant difference could be confirmed for the modified concretes in either the 5 min or the 30 min tests. On the other hand, in the condition of speed = 2 mm/s and time = 5 min, the wear rate for one application of MXenes by dropcasting was lower than the reference. With a higher speed and 30-min test, a greater effect on the wear rate occurred, which may be the result of tribochemical effects in the contact. It is clear that, in t

关键词： Tribology

Evidence for Two-stage Hardening in an Al-Zn-Mg-Cu Alloy processed by High-pressure Torsion

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ssRN 2022年

作者： dos santos, Igor Cuzzuol Mazzer, Eric M. Figueiredo, Roberto B. Langdon, Terence G. Rodrigues pereira, pedro Henrique Graduate Program in Metallurgical Materials and Mining Engineering Universidade Federal de Minas Gerais MG Belo Horizonte31270-901 Brazil Department of Materials Science and Engineering Universidade Federal de São Carlos SP São Carlos13565-905 Brazil Department of Metallurgical and Materials Engineering Universidade Federal de Minas Gerais MG Belo Horizonte31270-901 Brazil Materials Research Group Department of Mechanical Engineering University of Southampton SouthamptonSO17 1BJ United Kingdom

Experiments were conducted to assess the effect of torsional straining on the microstructural evolution of an Al-5.7Zn-1.8Mg-2.1Cu alloy containing dispersed second phase particles prior to deformation. The results show that the material exhibits two distinct and consecutive hardening stages when processed through 1/8, 1, 5, 30, 50 and 100 turns in high-pressure torsion (HpT). There is an initial increase in the Vickers hardness from ~120 Hv in the unprocessed state to ~240 Hv after 1 turn. In this first stage, hardening occurs primarily through the accumulation and rearrangement of dislocations into fine cells/subgrains. A quasi-stationary condition is achieved with further straining where the microhardness remains nearly constant and the grain size is ~140 nm up to 30 revolutions. Thereafter, the microstructure consists of ultrafine and slightly elongated grains but the second phases are continuously fragmented. This fragmentation produces a new hardening stage and the development of a uniform array of highly elongated grains with an average size of ~93 nm after 100 HpT turns. It is shown that this two-stage hardening is consistent with conventional Hall-petch strengthening and the development of the second stage is attributed to a reduction in grain boundary mobility due to the segregation of solutes. © 2022, The Authors. All rights reserved.

关键词： Aluminum alloys