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Solids, Volume 5, Issue 1 (March 2024) – 11 articles

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21 pages, 8770 KiB  
Article
Reactive Polymer Composite Microparticles Based on Glycidyl Methacrylate and Magnetite Nanoparticles
by Agnieszka Bukowska, Karol Bester, Sylwia Flaga and Wiktor Bukowski
Solids 2024, 5(1), 151-171; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010011 - 18 Mar 2024
Viewed by 681
Abstract
The modified suspension polymerization technique has been used for the preparation of composite microparticles from the mixture of glycidyl methacrylate (GMA), styrene (S), and divinylbenzene (DVB) in the presence of hydrophobized Fe3O4 nanoparticles. The obtained polymer microspheres were characterized using [...] Read more.
The modified suspension polymerization technique has been used for the preparation of composite microparticles from the mixture of glycidyl methacrylate (GMA), styrene (S), and divinylbenzene (DVB) in the presence of hydrophobized Fe3O4 nanoparticles. The obtained polymer microspheres were characterized using different instrumental and physicochemical techniques, modified with a zero-order PAMAM dendrimer, and impregnated with palladium(II) acetate solutions to immobilize palladium(II) ions. The resulting materials were preliminarily examined as catalysts in the Suzuki reaction between 4-bromotoluene and phenylboronic acid. It was found that the addition of magnetite particles to the composition of monomers provided polymer microparticles with embedded magnetic nanoparticles. The composite microparticles obtained showed a complex, multi-hollow, or raspberry-like morphology. After their modification, they could serve as recyclable catalysts for reactions that include both 4-bromotoluene and several other aryl bromides. Full article
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11 pages, 4682 KiB  
Article
Direct Synthesis of CuP2 and Cu3P and Their Performance as Electrocatalysts for Hydrogen Evolution, Oxygen Evolution, and Oxygen Reduction Reactions
by Xiao Ma, Xueni Huang and Abdessadek Lachgar
Solids 2024, 5(1), 140-150; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010010 - 7 Mar 2024
Viewed by 718
Abstract
Copper phosphides are promising materials for energy conversion applications because of their unique electronic structure and controllable composition. Two stoichiometric copper phosphides, CuP2 and Cu3P, were prepared by direct wet-chemical synthesis using red phosphorus. They were characterized by powder X-ray [...] Read more.
Copper phosphides are promising materials for energy conversion applications because of their unique electronic structure and controllable composition. Two stoichiometric copper phosphides, CuP2 and Cu3P, were prepared by direct wet-chemical synthesis using red phosphorus. They were characterized by powder X-ray diffraction, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. The precursor selection, reaction temperature, time and solvent composition were also studied. CuP2 is the thermodynamically more stable product, but Cu3P is more commonly obtained. This work demonstrated that higher temperature helps in CuP2 formation. More importantly, using more trioctylphosphine oxide helps control the morphology leading to crystal growth along the crystallographic a-axis. CuP2 and Cu3P were tested for hydrogen evolution, oxygen evolution, and oxygen reduction reactions. CuP2 works better for HER in acidic conditions and OER in general, and Cu3P showed better activity than CuP2 for HER and ORR in an alkaline medium. This study has led to a simple approach to the synthesis of CuP2 nanowires. Full article
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17 pages, 5427 KiB  
Article
Microstructure-Based CZE Model for Crack Initiation and Growth in CGI: Effects of Graphite-Particle Morphology and Spacing
by Xingling Luo, Konstantinos P. Baxevanakis and Vadim V. Silberschmidt
Solids 2024, 5(1), 123-139; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010009 - 1 Mar 2024
Viewed by 788
Abstract
Compacted graphite iron (CGI) is an engineering material with the potential to fill the application gap between flake- and spheroidal-graphite irons thanks to its unique microstructure and competitive price. Despite its wide use and considerable past research, its complex microstructure often leads researchers [...] Read more.
Compacted graphite iron (CGI) is an engineering material with the potential to fill the application gap between flake- and spheroidal-graphite irons thanks to its unique microstructure and competitive price. Despite its wide use and considerable past research, its complex microstructure often leads researchers to focus on models based on representative volume elements with multiple particles, frequently overlooking the impact of individual particle shapes and interactions between the neighbouring particles on crack initiation and propagation. This study focuses on the effects of graphite morphology and spacing between inclusions on the mechanical and fracture behaviours of CGI at the microscale. In this work, 2D cohesive-zone-element-based models with different graphite morphologies and spacings were developed to investigate the mechanical behaviour as well as crack initiation and propagation. ImageJ and scanning electron microscopy were used to characterise and analyse the microstructure of CGI. In simulations, both graphite particles and metallic matrix were assumed isotropic and ductile. Cohesive zone elements (CZEs) were employed in the whole domain studied. It was found that graphite morphology had a negligible effect on interface debonding but nodular inclusions can notably enhance the stiffness of the material and effectively impede the propagation of cracks within the matrix. Besides, a small distance between graphite particles accelerates the crack growth. These results can be used to design and manufacture better metal-matrix composites. Full article
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13 pages, 6456 KiB  
Article
Uncovering the Effects of Non-Hydrostaticity on Pressure-Induced Phase Transformation in Xenotime-Structured TbPO4
by Jai Sharma and Corinne E. Packard
Solids 2024, 5(1), 110-122; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010008 - 16 Feb 2024
Cited by 1 | Viewed by 578
Abstract
The pressure-induced phase transformations of rare earth orthophosphates (REPO4s) have become increasingly relevant in ceramic matrix composite (CMC) research; however, understanding of the shear-dependence of these transformations remains limited. This study employs diamond anvil cell experiments with three pressure media (neon, [...] Read more.
The pressure-induced phase transformations of rare earth orthophosphates (REPO4s) have become increasingly relevant in ceramic matrix composite (CMC) research; however, understanding of the shear-dependence of these transformations remains limited. This study employs diamond anvil cell experiments with three pressure media (neon, KCl, sample itself/no medium) to systematically assess the effect of shear on the phase transformations of TbPO4. Results show a lowering of the TbPO4 transformation onset pressure (Ponset) as well as an extension of the xenotime–monazite phase coexistence range under non-hydrostatic conditions. The TbPO4 Ponset under no medium (4.4(3) GPa) is the lowest REPO4 Ponset reported to date and represents a ~50% drop from the hydrostatic Ponset. Enthalpic differences likely account for lower Ponset values in TbPO4 compared to DyPO4. Experiments also show scheelite may be the post-monazite phase of TbPO4; this phase is consistent with observed and predicted REPO4 transformation pathways. Full article
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12 pages, 2873 KiB  
Article
Luminous Transmittance and Color Rendering Characteristics of Evaporated Chalcopyrite Thin Films for Semitransparent Photovoltaics
by Cecilia Guillén
Solids 2024, 5(1), 98-109; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010007 - 8 Feb 2024
Viewed by 686
Abstract
The luminous transmittance and the color rendering index of daylight through semitransparent photovoltaic glazing are essential parameters for visual comfort indoors, and they must be considered for different absorber materials that were traditionally developed for opaque solar cells, such as those of the [...] Read more.
The luminous transmittance and the color rendering index of daylight through semitransparent photovoltaic glazing are essential parameters for visual comfort indoors, and they must be considered for different absorber materials that were traditionally developed for opaque solar cells, such as those of the chalcopyrite type. With this aim, various chalcopyrite compounds (CuInSe2, CuInS2 and CuGaS2) were prepared by means of evaporation and then measured to obtain their optical absorption spectra. These experimental data are used here to calculate the solar absorptance (αS), luminous transmittance (τL) and color rendering index (Ra) as a function of the chalcopyrite film thickness. The comparative analysis of the different factors indicates that 70 nm thick CuInSe2 is optimal to guarantee excellent visual comfort (τL = 50% and Ra = 93%) while absorbing as much solar irradiance (αS = 37%) as 130 nm thick CuInS2 or 900 nm thick CuGaS2. The second option (130 nm thick CuInS2) is also considered good (τL = 40% and Ra = 80%), but for CuGaS2, the thickness should be kept below 250 nm in order to obtain a suitable color rendering Ra ≥ 60%. Full article
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14 pages, 28434 KiB  
Article
Durability Prediction of Cyclically Loaded CP-W800 Fillet Welds
by Dejan Tomažinčič, Peter Zobec, Marko Vrh, Aleš Gosar, Jurij Švegelj, Matic Muc, Vili Malnarič, Jernej Klemenc and Domen Šeruga
Solids 2024, 5(1), 84-97; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010006 - 1 Feb 2024
Viewed by 646
Abstract
Two methods of durability prediction of fillet welds were researched in this study. Namely, the structural Hot-Spot method and the structural stress method fe-safe Verity were applied to fatigue life estimation of a double plate lap fillet weld made of high-strength complex phase [...] Read more.
Two methods of durability prediction of fillet welds were researched in this study. Namely, the structural Hot-Spot method and the structural stress method fe-safe Verity were applied to fatigue life estimation of a double plate lap fillet weld made of high-strength complex phase CP-W800 steel. Durability predictions were compared against available high-cycle fatigue experimental data obtained for the same weld detail and material. Both 2D and 3D finite element meshes were considered in the simulations. It was shown that comparable predictions were obtained using either the Hot-Spot method or the fe-safe Verity module in the case of the 3D FE mesh. On the contrary, a less conservative durability prediction was observed using the Hot-Spot method and a more conservative durability prediction was gained using the fe-safe Verity module in the case of the 2D FE mesh due to a different consideration of stress concentration around the weld. Full article
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18 pages, 22595 KiB  
Article
Microwave Absorption Properties of Ceramics Based on BiFeO3 Modified with Ho
by Pavel Astafev, Konstantin Andryushin, Aleksey Pavelko, Alexander Lerer, Yakov Reizenkind, Ekaterina Glazunova, Lidiya Shilkina, Inna Andryushina, Alexandr Nagaenko and Larisa Reznichenko
Solids 2024, 5(1), 66-83; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010005 - 17 Jan 2024
Viewed by 657
Abstract
Ceramic samples of Bi1−xHoxFeO3, where x = 0.00–0.50, with a modifier concentration variation step ∆x = 0.05–0.10, were prepared by a two-step solid-phase synthesis followed by sintering using conventional ceramic technology. X-ray phase analysis showed [...] Read more.
Ceramic samples of Bi1−xHoxFeO3, where x = 0.00–0.50, with a modifier concentration variation step ∆x = 0.05–0.10, were prepared by a two-step solid-phase synthesis followed by sintering using conventional ceramic technology. X-ray phase analysis showed that all the solid solutions studied were formed in the presence of impurities. With increasing Ho concentration, a non-monotonic shift in all loss maxima towards the low-frequency region is observed, as well as an increase in their half-width. An increase in the external temperature leads to a monotonic shift in the absorption maxima towards the low-frequency region, which enables the necessary control of the microwave parameters in the X band. A conclusion has been drawn on the feasibility of using the data obtained in the design of new functional materials based on BiFeO3, as well as devices with thermally controlled frequency. Full article
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21 pages, 4460 KiB  
Review
Two-Dimensional Ferroelectrics: A Review on Applications and Devices
by Gabriella Maria De Luca and Andrea Rubano
Solids 2024, 5(1), 45-65; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010004 - 16 Jan 2024
Viewed by 1682
Abstract
Over the last few years, research activities have seen two-dimensional (2D) materials become protagonists in the field of nanotechnology. In particular, 2D materials characterized by ferroelectric properties are extremely interesting, as they are better suited for the development of miniaturized and high-performing devices. [...] Read more.
Over the last few years, research activities have seen two-dimensional (2D) materials become protagonists in the field of nanotechnology. In particular, 2D materials characterized by ferroelectric properties are extremely interesting, as they are better suited for the development of miniaturized and high-performing devices. Here, we summarize the recent advances in this field, reviewing the realization of devices based on 2D ferroelectric materials, like FeFET, FTJ, and optoelectronics. The devices are realized with a wide range of material systems, from oxide materials at low dimensions to 2D materials exhibiting van der Waals interactions. We conclude by presenting how these materials could be useful in the field of devices based on magnons or surface acoustic waves. Full article
(This article belongs to the Special Issue Recent Advance in Ferroelectric Composites)
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16 pages, 3976 KiB  
Article
The Origin of the Yellow Luminescence Band in Be-Doped Bulk GaN
by Michael A. Reshchikov and Michal Bockowski
Solids 2024, 5(1), 29-44; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010003 - 4 Jan 2024
Viewed by 864
Abstract
Photoluminescence (PL) from Be-doped bulk GaN crystals grown by the High Nitrogen Pressure Solution method was studied and compared with PL from GaN:Be layers on sapphire grown by molecular beam epitaxy and metalorganic chemical vapor deposition techniques. The yellow luminescence band in the [...] Read more.
Photoluminescence (PL) from Be-doped bulk GaN crystals grown by the High Nitrogen Pressure Solution method was studied and compared with PL from GaN:Be layers on sapphire grown by molecular beam epitaxy and metalorganic chemical vapor deposition techniques. The yellow luminescence band in the latter is caused by the isolated BeGa acceptor (the YLBe band), while the broad yellow band in bulk GaN:Be crystals is a superposition of the YLBe band and another band, most likely the CN-related YL1 band. The attribution of the yellow band in bulk GaN:Be crystals to the BeGaON complex (a deep donor) is questioned. Full article
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15 pages, 14674 KiB  
Article
Elastic Stress Field beneath a Sticking Circular Contact under Tangential Load
by Emanuel Willert
Solids 2024, 5(1), 14-28; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010002 - 26 Dec 2023
Cited by 1 | Viewed by 720
Abstract
Based on a potential theoretical approach, the subsurface stress field is calculated for an elastic half-space which is subject to normal and uniaxial tangential surface tractions that—in the case of elastic decoupling—correspond to rigid normal and tangential translations of a circular surface domain. [...] Read more.
Based on a potential theoretical approach, the subsurface stress field is calculated for an elastic half-space which is subject to normal and uniaxial tangential surface tractions that—in the case of elastic decoupling—correspond to rigid normal and tangential translations of a circular surface domain. The stress fields are obtained explicitly and in closed form as the imaginary parts of compact complex-valued expressions. The stress state in the surface and on the central axis are considered in detail. As, within specific approximations that have been discussed at length in the literature, any tangential contact problem with friction can be understood as a certain incremental series of such rigid translations, the solutions presented here can serve as the basis of very fast superposition algorithms for the analysis of subsurface stress fields in general tangential contact problems with friction. This idea is demonstrated by means of the frictional tangential contact between an elastic half-space and a rigid cylindrical flat punch with rounded corners. Full article
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13 pages, 845 KiB  
Article
Surface Characterization and Bulk Property Analysis of Aluminum Powders Treated with Hydrophobic Coatings: Stearic Acid and Phenyl-Phosphonic Acid
by Bellamarie Ludwig
Solids 2024, 5(1), 1-13; https://0-doi-org.brum.beds.ac.uk/10.3390/solids5010001 - 22 Dec 2023
Viewed by 824
Abstract
Stearic and phenyl-phosphonic acids were applied to fine aluminum particles to understand their effect on the surface chemical composition and bulk properties of the surface-treated powders. During the solution phase deposition process, the surface composition changes chemically through a condensation reaction between the [...] Read more.
Stearic and phenyl-phosphonic acids were applied to fine aluminum particles to understand their effect on the surface chemical composition and bulk properties of the surface-treated powders. During the solution phase deposition process, the surface composition changes chemically through a condensation reaction between the acid and particle surface hydroxyl groups, forming covalent chemical bonds. The retention of both types of acids was verified through characterization using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The presence of stearic acid on the particle surface was observed through signature absorbance peaks, including interfacial C-O bonding modes, carboxylate, and carbonyl moieties, all present on both the treated powder. Spectra using XPS showed an increase in -CH relative intensity signal on the particle surface when compared to the raw material when considering the the carbon 2p photoelectron peak. Similar findings confirmed the presence of the phenyl-phosphonic acid when comparing to the raw material. The IR spectrum confirmed the presence of P-O-Al, P-O, and phosponates as a result of the surface bonding between the reagent and particles. XPS always provided evidence through the presence of phosphorous 2p and 2s photoelecton peaks at 191.3 and 133.4 eV, respectively. The bulk properties of both surface treated powders improved, as shown through improved apparent/tap density and a decreased Hausner Ratio (Group C to Group A behavior). Rheological characterization provided additional evidence by showing a reduced specific energy, flow rate index, and cohesion. The particle packing was improved as evidenced through reduced compressibility as a function of applied normal stress. Full article
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