Crystals

16 pages, 4366 KB

Open AccessArticle

Influence of Fly Ash on the Macro Properties and Mineral Crystal Characteristics of Alkali-Activated Slag Grouting Materials

by Guodong Huang, Jiahao Xu, Jun Qi, Fengan Zhang and Baoxuan Dou

Crystals 2025, 15(11), 999; https://doi.org/10.3390/cryst15110999 - 20 Nov 2025

Viewed by 231

Abstract

Alkali-activated slag grouting materials exhibited excellent mechanical properties but still faced technical challenges such as insufficient fluidity and overly rapid setting. To enhance their workability, this study introduced fly ash as a modifying component, leveraging its morphological and activity effects to systematically investigate [...] Read more.

Alkali-activated slag grouting materials exhibited excellent mechanical properties but still faced technical challenges such as insufficient fluidity and overly rapid setting. To enhance their workability, this study introduced fly ash as a modifying component, leveraging its morphological and activity effects to systematically investigate the composite influence on fluidity, setting time, and compressive strength. The mechanism was further elucidated through microstructural analysis of the mineral crystallization characteristics of polycondensation products. The results indicated that with increasing fly ash content, the fluidity of the grouting material continuously improved, and both the initial and final setting times were significantly prolonged, albeit at the expense of a gradual decline in compressive strength. At a 20% fly ash content, the fluidity spread increased to 292 mm, the initial and final setting times were extended to 70 min and 103 min, respectively, while the 1 d and 28 d compressive strengths reached 11.8 MPa and 48.1 MPa, achieving an optimal overall performance that met practical grouting requirements. Microscopic analysis revealed that fly ash enhanced the rheological properties and delayed the setting process through the “ball-bearing effect” and its low early-age reactivity. However, as the fly ash content rose, the active calcium content in the system continuously decreased, inhibiting the formation and development of key mineral crystals such as calcium silicate and calcium aluminosilicate, thereby leading to the reduction in compressive strength. Full article

(This article belongs to the Section Crystal Engineering)

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20 pages, 7256 KB

Open AccessArticle

Influence of Y₂O₃ Content and Sintering Temperature on Microstructure and Mechanical Properties of YSZ Ceramics

by Madi Abilev, Dias Yerbolat, Mazhyn Skakov, Almira Zhilkashinova, Alexandr Pavlov and Igor Karpov

Crystals 2025, 15(11), 1002; https://doi.org/10.3390/cryst15111002 - 20 Nov 2025

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Abstract

This study investigates the influence of Y₂O₃ content and sintering temperature on the microstructure, phase composition, and physico-mechanical properties of zirconia-based ceramics with Al₂O₃ addition. It was shown that varying the stabilizer content within 3.0–6.0 wt.% Y [...] Read more.

This study investigates the influence of Y₂O₃ content and sintering temperature on the microstructure, phase composition, and physico-mechanical properties of zirconia-based ceramics with Al₂O₃ addition. It was shown that varying the stabilizer content within 3.0–6.0 wt.% Y₂O₃ leads to observable changes in the phase composition and grain size, as well as affecting the density and microhardness of the material. The sintering conditions ensuring the required density and homogeneous microstructure at moderate temperatures were determined. This research is aimed at optimizing synthesis and heat treatment parameters to produce a dense material with minimal porosity and stable mechanical characteristics. The samples were shaped by uniaxial pressing and sintered in the temperature range of 1530–1570 °C. The structure and phase composition were analyzed using X-ray diffraction and scanning electron microscopy, while the physico-mechanical properties were evaluated by measuring apparent density, porosity, and microhardness. The sintering temperature of 1550 °C was identified as optimal for achieving the highest performance characteristics while maintaining structural homogeneity. The addition of Al₂O₃ contributes to a reduction in the sintering temperature without compromising the material’s properties. Full article

(This article belongs to the Section Polycrystalline Ceramics)

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19 pages, 5760 KB

Open AccessArticle

Effect of Over-Temperature on Creep Damage of Bi-Based Brazing Filler Alloy

by Jun Hong, Tao Wang, Baoyin Zhu, Dongpeng Li, Haitao Dong, Dungui Zuo and Gongye Zhang

Crystals 2025, 15(11), 1001; https://doi.org/10.3390/cryst15111001 - 20 Nov 2025

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Abstract

This work investigates the creep damage behavior and life prediction of Bi-based brazing alloys and their corresponding joints under intermittent over-temperature conditions, and proposes an integrated real-time monitoring and analytical framework. Temperature–time histories of structural components are acquired using both fixed and mobile [...] Read more.

This work investigates the creep damage behavior and life prediction of Bi-based brazing alloys and their corresponding joints under intermittent over-temperature conditions, and proposes an integrated real-time monitoring and analytical framework. Temperature–time histories of structural components are acquired using both fixed and mobile infrared thermography systems to quantify thermal fluctuations. These data are subsequently coupled with a materials database and an enhanced Kachanov–Rabotnov creep damage constitutive model to simulate the evolution of thermally induced stresses and the accumulation of damage. Structural parameters, including weld seam thickness and porosity, are incorporated to perform sensitivity analyses. Experimental findings reveal a pronounced decline in the yield strength of the Bi-based brazing alloy with increasing temperature, identifying this degradation as the principal driver of creep failure. Fractographic observations show intergranular rupture characteristics during creep, in distinct contrast to the transgranular fracture mechanisms observed under tensile loading. Model predictions exhibit excellent concordance with experimental data and faithfully capture the life evolution across varying thermal–mechanical conditions. The results demonstrate that the proposed system enables real-time assessment of the health state, residual life, and failure risk of critical components. Moreover, it provides a robust theoretical foundation and practical guidance for operational safety management and maintenance decision-making in large enclosed containment structures, including those employed in nuclear power systems. Full article

(This article belongs to the Section Crystalline Metals and Alloys)

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17 pages, 1865 KB

Open AccessArticle

Halogens On, H-Bonds Off—Insights into Structure Control of Dihalogenated Imidazole Derivatives

by Luca Mensing, Marcus Layh and Marian Hebenbrock

Crystals 2025, 15(11), 1000; https://doi.org/10.3390/cryst15111000 - 20 Nov 2025

Viewed by 332

Abstract

Halogen bonds play an important role in the targeted generation of solid-state structures, with polyhalogenated compounds enabling the simultaneous formation of various interactions. In this manuscript, we investigate the interactions of dihalogenated compounds in the solid state. Unlike investigated in previous studies, the [...] Read more.

Halogen bonds play an important role in the targeted generation of solid-state structures, with polyhalogenated compounds enabling the simultaneous formation of various interactions. In this manuscript, we investigate the interactions of dihalogenated compounds in the solid state. Unlike investigated in previous studies, the introduction of protective groups in these compounds prevents the formation of dominant hydrogen bonds. The structures of diiodo imidazole derivatives are compared with the analogous dibromo compounds. A total of four different protective groups (two benzylic and two oxycarbonyl protective groups) are introduced and the respective compounds are characterized by X-ray crystallography. The significance of the protective groups for the solid-state structure can be distinguished on the basis of the additional donor atoms and functional groups. It can be seen that the iodo compounds in particular are capable of forming halogen bonds and that additional structural motifs can be generated by suitable protective groups. Full article

(This article belongs to the Special Issue Analysis of Halogen and Other σ-Hole Bonds in Crystals (2nd Edition))

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21 pages, 5717 KB

Open AccessArticle

Effect of Partial Fe-Substitution by Y and/or Ce in BaFeO₃-Based Oxides on Oxygen Diffusion

by Anna Khodimchuk, Irina Svishch, Egor Gordeev and Natalia Porotnikova

Crystals 2025, 15(11), 998; https://doi.org/10.3390/cryst15110998 - 19 Nov 2025

Viewed by 352

Abstract

The chemical diffusion coefficients of oxygen (

D^{δ}

) for the oxides BaFe_0.9Ce_0.1O_3−δ (BFC10), BaFe_0.9Y_0.1O_3−δ (BFY10), and BaFe_0.8Ce_0.1Y_0.1O_3−δ (BFCY1010) were determined by [...] Read more.

The chemical diffusion coefficients of oxygen (

D^{δ}

) for the oxides BaFe_0.9Ce_0.1O_3−δ (BFC10), BaFe_0.9Y_0.1O_3−δ (BFY10), and BaFe_0.8Ce_0.1Y_0.1O_3−δ (BFCY1010) were determined by the oxygen pressure relaxation method in the T = 600–800 °C and pO₂ = 0.1–3.5 kPa ranges. The oxygen diffusion coefficients at 700 °C were found to be 1.80·10⁻⁵, 3.92·10⁻⁵, and 1.85·10⁻⁵ cm²/s for BFC10, BFY10, and BFCY1010, respectively. It was established that the volume oxygen diffusion increases in the order

D^{δ}

(BFY10) >

D^{δ}

(BFCY1010) >

D^{δ}

(BFC10), which correlates with the data on oxygen non-stoichiometry (δ), and is associated with the oxygen vacancy content in oxides. The values of effective activation energies were determined: 1.21 ± 0.04, 1.31 ± 0.10, and 1.18 ± 0.09 eV for BFC10, BFY10, and BFCY1010, respectively. A comparative analysis of oxygen transport highlights the potential of co-doped BaFe_0.8Ce_0.1Y_0.1O_3−δ as a promising cobalt-free cathode material with triple (oxygen, proton, electron) conductivity. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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3 pages, 145 KB

Open AccessEditorial

Microstructure and Mechanical Behavior of Structural Materials: 2nd Edition

by Saif Haider Kayani and Byung-Joo Kim

Crystals 2025, 15(11), 997; https://doi.org/10.3390/cryst15110997 - 19 Nov 2025

Viewed by 241

Abstract

Metallic materials are the workhorses of structural applications and remain central to modern engineering across energy, transportation, process equipment, and extreme-environment service [...] Full article

(This article belongs to the Special Issue Microstructure and Mechanical Behaviour of Structural Materials: 2nd Edition)

3 pages, 128 KB

Open AccessEditorial

Research on Electrolytes and Energy Storage Materials

by Bhargav Akkinepally

Crystals 2025, 15(11), 996; https://doi.org/10.3390/cryst15110996 - 19 Nov 2025

Viewed by 274

Abstract

The global transition toward sustainable and efficient energy storage solutions has placed research on electrolytes and energy storage materials at the heart of scientific and technological innovation [...] Full article

(This article belongs to the Special Issue Research on Electrolytes and Energy Storage Materials)

6 pages, 212 KB

Open AccessEditorial

Crystallization of High Performance Metallic Materials (2nd Edition)

by Chao Chen and Wangzhong Mu

Crystals 2025, 15(11), 995; https://doi.org/10.3390/cryst15110995 - 18 Nov 2025

Viewed by 358

Abstract

Crystallization generally refers to the material processing in which a solid phase nucleates within a liquid or solid matrix [...] Full article

(This article belongs to the Special Issue Crystallization of High Performance Metallic Materials (2nd Edition))

20 pages, 7303 KB

Open AccessArticle

Unified Interpretation of Angular and Cumulative Angular Phase Representations with Best-Practice Guidelines for Differential Phase Shift Extraction in Nematic Liquid Crystal-Based Reconfigurable Phase Shifters

by Jinfeng Li, Haorong Li and Yunchen Xiao

Crystals 2025, 15(11), 994; https://doi.org/10.3390/cryst15110994 - 18 Nov 2025

Viewed by 333

Abstract

Electromagnetic phase reconfigurability is a critical functionality for many emerging applications in electronics, defence, and other disruptive technologies. This work addresses a significant challenge in developing nematic liquid crystal (NLC)-based phase shifters: inaccurate and ambiguous calculations of differential phase shift, which can jeopardise [...] Read more.

Electromagnetic phase reconfigurability is a critical functionality for many emerging applications in electronics, defence, and other disruptive technologies. This work addresses a significant challenge in developing nematic liquid crystal (NLC)-based phase shifters: inaccurate and ambiguous calculations of differential phase shift, which can jeopardise on-time, on-budget device development. We investigate and correct two vulnerable cases of these calculation errors, demonstrated using a 60 GHz strip line and a 300 GHz coaxial line. For completeness, we also present a third case—a 1 mm long 60 GHz strip line—that correctly calculates phase shift, illustrating a “false positive” scenario. A unique contribution of this paper is the statistical analysis of how often these different phase shift processing errors occur during NLC delay line parameterisation. This statistical insight provides practical guidance for research and development. By numerically testing common assumptions, we establish traceable know-how to support smarter design decisions for radiofrequency (RF) engineers and academics. This work aims to advance NLC devices beyond classical display applications towards commercial viability. It also serves as a valuable reference and educational resource for students, physicists, and designers working on the precise phase characterisation of NLC-based reconfigurable devices. Full article

(This article belongs to the Collection Liquid Crystals and Their Applications)

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10 pages, 5532 KB

Open AccessArticle

A Long-Wave Infrared Circularly Polarized Photodetector Based on an Array of Trapezoidal Silicon Pillars

by Bo Cheng, Yuxiao Zou, Taohua Liang, Ansheng Ye, Kunpeng Zhai and Longfeng Lv

Crystals 2025, 15(11), 993; https://doi.org/10.3390/cryst15110993 - 17 Nov 2025

Viewed by 362

Abstract

Integrating metasurface-based polarizing filters atop photodetectors enables the expansion of detection capabilities from intensity to polarization, offering significant potential for applications requiring high-precision discrimination in scientific, industrial, and defense sectors. However, such metasurfaces often introduce optical efficiency losses. Here, we present a long-wave [...] Read more.

Integrating metasurface-based polarizing filters atop photodetectors enables the expansion of detection capabilities from intensity to polarization, offering significant potential for applications requiring high-precision discrimination in scientific, industrial, and defense sectors. However, such metasurfaces often introduce optical efficiency losses. Here, we present a long-wave infrared (8.6 μm) circularly polarized photodetector capable of direct chiral discrimination, eliminating the need for additional optical components. The polarization selectivity arises from Guided-Mode resonances (GMRs) excited by two horizontally offset right-trapezoidal unit cells within a chiral metasurface. This design exhibits a pronounced transmittance contrast (~100%) between left circularly polarized light (LCP) and right circularly polarized light (RCP) while maintaining fabrication simplicity via a conventional single-step lithographic process. The proposed detector is expected to achieve high-dimensional physical characterization by resolving polarization-encoded vectorial information, demonstrating enhanced performance in complex environments. Full article

(This article belongs to the Special Issue Metamaterials and Their Devices, Second Edition)

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17 pages, 7895 KB

Open AccessArticle

Electrolytic-Plasma Nitriding of Austenitic Stainless Steels After Mechanical Surface Treatment

by Bauyrzhan Rakhadilov, Zarina Satbayeva, Almasbek Maulit, Nurlat Kadyrbolat and Anuar Rustemov

Crystals 2025, 15(11), 992; https://doi.org/10.3390/cryst15110992 - 17 Nov 2025

Viewed by 335

Abstract

In this work, the effect of preliminary mechanical surface treatment on the kinetics of formation, phase composition, and functional properties of the nitrided layer during electrolytic-plasma nitriding (EPN) of austenitic stainless steel 12Kh18N10T (AISI 321) was investigated. In contrast to traditional approaches, for [...] Read more.

In this work, the effect of preliminary mechanical surface treatment on the kinetics of formation, phase composition, and functional properties of the nitrided layer during electrolytic-plasma nitriding (EPN) of austenitic stainless steel 12Kh18N10T (AISI 321) was investigated. In contrast to traditional approaches, for the first time, this work establishes a direct correlation between the degree of surface deformation induced by shot peening and the formation of the expanded austenite (γN) phase under low-temperature plasma conditions. Quantitative X-ray phase analysis revealed a lattice parameter expansion of Δa/a₀ ≈ 1.4–1.8% and a gradual transformation of γ-Fe → γN without the formation of CrN nitrides at moderate intensity of preliminary treatment. According to SEM/EDS data and microhardness profiles, a multilayer structure was formed, consisting of a thin surface film of CrN/Fe₄N, a developed γN zone with a thickness of 12–15 µm, and a stable austenitic γ-Fe matrix. The surface microhardness increases to 880 ± 20 HV, while the friction coefficient decreases to 0.35–0.40, corresponding to a wear reduction of approximately 55% compared to the initial steel. The results provide a mechanistic understanding of nitrogen diffusion through defect-enriched subsurface layers and show that optimal preliminary deformation (d = 6 mm, v = 40 Hz, t = 20 min) promotes controlled formation of the γN phase with minimal lattice instability. The proposed combined approach—shot peening + EPN—is an effective method for producing wear- and corrosion-resistant surfaces of austenitic steels under atmospheric plasma conditions. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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10 pages, 1697 KB

Open AccessArticle

Persistent PbI₂-Passivated Microdomains in As-Prepared MAPbI₃ Perovskite Thin Film Revealed by Spatially Resolved Photoluminescence and Raman Maps

by Bong-Geun Kim, Jiwon Choi, Taeji Seo, Hyun Sung Kim, Minseok Kwak, Joonkyung Jang, Songyi Lee and Myeongkee Park

Crystals 2025, 15(11), 991; https://doi.org/10.3390/cryst15110991 - 17 Nov 2025

Viewed by 375

Abstract

Methylammonium lead iodide (MAPbI₃) perovskite has been widely studied for its optoelectronic properties, but its polycrystalline thin films inevitably contain grain boundaries and defects that degrade performance and stability. PbI₂ is often considered a destabilizing agent in perovskites, yet it [...] Read more.

Methylammonium lead iodide (MAPbI₃) perovskite has been widely studied for its optoelectronic properties, but its polycrystalline thin films inevitably contain grain boundaries and defects that degrade performance and stability. PbI₂ is often considered a destabilizing agent in perovskites, yet it has also been reported to act as a passivation agent, making its role a subject of debate. Here, we performed integrated optical, photoluminescence (PL), and ultra-low-frequency Raman mapping on a 100 μm² region of MAPbI₃ thin films to study the roles of PbI₂. The analyses resolved α-phase MAPbI₃-rich, PbI₂-rich, and mixed-phase domains, revealing heterogeneous PbI₂ distribution with PL quenching at defect sites. In addition, after light-induced degradation, PL changes were governed by both the local microstructure and PbI₂ distribution. Notably, PbI₂-rich regions retained PL, evidencing a protective passivation effect. These findings demonstrate that the beneficial role of PbI₂ is key to designing more stable perovskite devices. Full article

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20 pages, 4333 KB

Open AccessArticle

Hydrogen Storage Capacity and Optoelectronic Response of Mechanically and Thermally Stable Lithium-Based Tetrahydrates (LiXH₄, X = B, Al, Mn), a DFT Approach

by Ahmad Hussain, Nawishta Jabeen, Ali Yaqoob, Aseel Smerat, Muhammad Adnan Qaiser and Naflaa A. Aldawsari

Crystals 2025, 15(11), 990; https://doi.org/10.3390/cryst15110990 - 16 Nov 2025

Viewed by 309

Abstract

In this work, density functional theory (DFT)-based first-principles investigations are performed by Generalized Gradient Approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional in the CASTEP code. These simulations provide the insights of the structural, electronic, optical, thermodynamic, mechanical and hydrogen storage gravimetric ratios of [...] Read more.

In this work, density functional theory (DFT)-based first-principles investigations are performed by Generalized Gradient Approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional in the CASTEP code. These simulations provide the insights of the structural, electronic, optical, thermodynamic, mechanical and hydrogen storage gravimetric ratios of lithium-based tetrahydrides (LiBH₄, LiAlH₄, and LiMnH₄) for hydrogen storage and photovoltaic (PV) applications. All these structures crystallize in orthorhombic Cmcm (No. 63) geometry with different lattice parameters and bonding strengths. Thermodynamic stabilities of hydrides are obtained by dispersion of phonons and phonon density of states. The measured band gaps of hydrides are 3.81 eV (LiBH₄), 4.60 eV (LiAlH₄), and 0.53 eV (LiMnH₄), which are calculated by GGA-PBE approach. Moreover, the optical characteristics with strong optical activity are observed from visible to ultraviolet (2 eV to 6 eV) regions. High dielectric response between 6 and 8 and absorption coefficient up to 10⁵ cm⁻¹ for hydrides are observed. Debye temperature has exceeded from 300 K to 600 K for all hydrides and saturation occurred closer to Dulong–Petit limit ~75 J mol⁻¹ K⁻¹. Mechanical stability in hydrides has been observed by Born-Hung mechanical stability criterion, demonstrating ductile nature. These natural hydrides have shown exceptional hydrogen storage capacities, as 18.5 wt% for LiBH₄, 10.6 wt% for LiAlH₄, and 6.1 wt% for LiMnH₄, are measured; these values have exceeded the U.S department of energy (DOE) targets (5.5 wt% H₂). These analyses prove that LiXH₄ (X = B, Al, Mn) hydrides are promising candidates for solid state hydrogen storage materials. Full article

(This article belongs to the Section Materials for Energy Applications)

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13 pages, 3846 KB

Open AccessArticle

Novel 2D Porous Metal–Organic Frameworks: Synthesis, X-Ray Structure, Thermal, and Hirshfeld Surface Analyses

by Rupam Sen, Mahananda Roy, Sriparna Sanyal, Arpan Dolui, Paula Brandão and Zhi Lin

Crystals 2025, 15(11), 989; https://doi.org/10.3390/cryst15110989 - 15 Nov 2025

Viewed by 321

Abstract

In the present study, we have developed a series of compounds [M(tcm)₂(bix)₄]_n [where M = Co (1), Ni (2), and Cu (3)] using tricyanomethanide (tcm) and 1,4-bis(imidazol-1-ylmethyl)benzene (bix) ligands. The compounds were [...] Read more.

In the present study, we have developed a series of compounds [M(tcm)₂(bix)₄]_n [where M = Co (1), Ni (2), and Cu (3)] using tricyanomethanide (tcm) and 1,4-bis(imidazol-1-ylmethyl)benzene (bix) ligands. The compounds were characterized by elemental analysis, PXRD, FT-IR and single-crystal X-ray crystallography. Single-crystal X-ray investigation of compounds 1, 2, and 3 shows the formation of the porous 2D structure. These 2D structures are further stacked to create a 3D network in the crystallographic space. All the compounds are thermally stable up to 300 °C, as revealed by the TGA. Hirshfeld surface analysis was carried out, and it reveals the existence of short intermolecular interactions between the layers. Full article

(This article belongs to the Special Issue Synthesis, Crystal Structures and Hirshfeld Surface Analysis of Coordination Compounds (3rd Edition))

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16 pages, 2615 KB

Open AccessArticle

A Novel High-Performance 2-to-4 Decoder Design Utilizing a Plasmonic Well and Suspended Graphene Nanoribbon

by Mohammad Javad Maleki and Mohammad Soroosh

Crystals 2025, 15(11), 988; https://doi.org/10.3390/cryst15110988 - 15 Nov 2025

Viewed by 319

Abstract

This paper presents a compact and high-performance 2-to-4 optical decoder based on a plasmonic well structure incorporating suspended graphene nanoribbons. By exploiting the tunable graphene’s chemical potential, the propagation and confinement of surface plasmon polaritons are dynamically controlled, enabling efficient routing of optical [...] Read more.

This paper presents a compact and high-performance 2-to-4 optical decoder based on a plasmonic well structure incorporating suspended graphene nanoribbons. By exploiting the tunable graphene’s chemical potential, the propagation and confinement of surface plasmon polaritons are dynamically controlled, enabling efficient routing of optical signals toward the output ports. Finite-difference time-domain simulations are employed to analyze the influence of channel geometry and graphene chemical potential on surface plasmon polariton propagation, refractive index, and transmission loss. The designed structure, featuring a 30 nm wide and 10 nm high plasmonic well, achieves a low propagation loss of 0.188 dB/µm and a high figure of merit of 1950 at 40 THz. The designed decoder exhibits a contrast ratio of 36.93 dB and crosstalk suppression of −36.93 dB, while occupying a remarkably small area (0.05 µm²), demonstrating superior optical performance and compactness compared to previously reported designs. These results confirm the potential of the proposed plasmonic well-based decoder as a fundamental component for next-generation nanoscale optical and plasmonic computing systems. Full article

(This article belongs to the Special Issue Recent Advances in Graphene and Other Two-Dimensional Materials)

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19 pages, 16822 KB

Open AccessArticle

Origin of Light-Colored Nephrite Relative to Green Nephrite in Ospa, Russia

by Yihan Li, Guanghai Shi and Jinhong Zhang

Crystals 2025, 15(11), 987; https://doi.org/10.3390/cryst15110987 - 15 Nov 2025

Viewed by 282

Abstract

In serpentinite-related green nephrite, light-colored nephrite commonly occurs as veins or interlayers at nearly every nephrite locality. However, its characteristics have been poorly understood. In this study, samples containing both green and light-colored nephrites from the Ospa deposit in East Sayan, Russia, were [...] Read more.

In serpentinite-related green nephrite, light-colored nephrite commonly occurs as veins or interlayers at nearly every nephrite locality. However, its characteristics have been poorly understood. In this study, samples containing both green and light-colored nephrites from the Ospa deposit in East Sayan, Russia, were selected for integrated petrographic and geochemical analyses. Petrographic observations identified three domains transitioning from green to light-colored nephrite: the green domain, the transition band, and the light-colored domain. Although both the green domain and the transition band consist of oriented tremolite fibers, the fiber orientations differ between these two domains. In contrast, the light-colored domain typically exhibits non-oriented fibers and fine grains with flow textures. Geochemical data reveal a decrease in Cr and Ni contents from the green domain to the light-colored domain, while Fe and Mn contents remain relatively stable. Additionally, significant enrichments of Hf and Zr were observed in the light-colored domain. These observations suggest that the light-colored domain precipitated from a later-stage fluid distinct from the fluid sources responsible for the green nephrite, with the transition band resulting from the late fluid reacting with syn-deformational green nephrite. Thus, a model for light-colored nephrite formation can be simplified as a process in which a late fluid, low in Cr and Ni, precipitates predominantly within the stretched structures of green nephrite. UV-Vis spectroscopy on the studied samples, combined with a comparative analysis of chromogenic complexes in nephrites of various colors, further indicates that the green hue of the specific grayish-green in light-colored nephrite is dominantly controlled by Cr, whereas its grayish hue is modified by the ratio of (Fe + Mn) to Cr. These findings elucidate the formation sequence and genetic mechanisms behind light-colored nephrite, offering a thorough comprehension of nephritization in serpentinite-related deposits. Full article

(This article belongs to the Section Mineralogical Crystallography and Biomineralization)

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16 pages, 3585 KB

Open AccessArticle

Crystal Structure and Optical Behavior of Diamino-Substituted 1,4-Benzoquinones

by Anastasija Gaile, Sergey Belyakov, Svetlana Zhizhkun and Nelli Batenko

Crystals 2025, 15(11), 986; https://doi.org/10.3390/cryst15110986 - 15 Nov 2025

Viewed by 270

Abstract

Reactions of benzoquinone with amines can potentially lead to the formation of coupled merocyanine or merocyanine/polymethine systems. In this study, several diamino-substituted 1,4-benzoquinones were synthesized. The crystal structures for three derivatives bearing 2-hydroxyethylamino or 2-(2-hydroxyethoxy)ethyl)amino substituents were determined using single-crystal X-ray crystallographic analysis. [...] Read more.

Reactions of benzoquinone with amines can potentially lead to the formation of coupled merocyanine or merocyanine/polymethine systems. In this study, several diamino-substituted 1,4-benzoquinones were synthesized. The crystal structures for three derivatives bearing 2-hydroxyethylamino or 2-(2-hydroxyethoxy)ethyl)amino substituents were determined using single-crystal X-ray crystallographic analysis. A characteristic feature of all molecular structures is the presence of an extensive network of intermolecular interactions, significantly stabilized by hydrogen bonding. Additionally, changes in the optical behavior of the synthesized compounds were monitored by UV-Vis spectroscopy in the presence of Cu²⁺ and Zn²⁺ ions, followed by the addition of primary, secondary or biogenic (butane-1,4-diamine) amines. Full article

(This article belongs to the Special Issue Analysis of Halogen and Other σ-Hole Bonds in Crystals (2nd Edition))

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17 pages, 2576 KB

Open AccessArticle

Plasmon Dispersion in Two-Dimensional Systems with Non-Coulomb Interaction

by Levente Máthé, Ilinca Lianu, Adrian Calborean and Ioan Grosu

Crystals 2025, 15(11), 985; https://doi.org/10.3390/cryst15110985 - 15 Nov 2025

Viewed by 289

Abstract

We theoretically study plasmon dispersion within the random-phase approximation in two-dimensional systems, including undoped and doped monolayer graphene at zero and finite temperatures, and hole- and electron-doped monolayer

X Se

(

X = In, Ga

) and disordered two-dimensional electron gas at [...] Read more.

We theoretically study plasmon dispersion within the random-phase approximation in two-dimensional systems, including undoped and doped monolayer graphene at zero and finite temperatures, and hole- and electron-doped monolayer

X Se

(

X = In, Ga

) and disordered two-dimensional electron gas at zero temperature, in the presence of a non-Coulomb interaction of the form

\sim r^{- η}

. Our findings show that the parameter

η

, which characterizes the non-Coulombic nature of the interaction, strongly affects the dependence of the plasmon frequency on the wave vector in the long-wavelength limit. Furthermore, the carrier density dependence of the plasmon frequency is unaffected by the parameter

η

in this regime. For

η = 1

, corresponding to the Coulomb case, the well-known results are fully recovered for all systems studied here. Full article

(This article belongs to the Special Issue Research on Electrolytes and Energy Storage Materials (2nd Edition))

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14 pages, 2965 KB

Open AccessArticle

Study on Microstructure Evolution and Influencing Factors of Pure Copper Wire After Directional Heat Treatment

by Hao Xu, Xin Dong, Feixiang Chen, Yang Chen and Guang Chen

Crystals 2025, 15(11), 984; https://doi.org/10.3390/cryst15110984 - 14 Nov 2025

Viewed by 309

Abstract

The Ohon Continuous Casting is the main method for preparing single crystal copper wire, and it is also the research hotspot at present, but it is difficult to directly cast ultrafine single crystal copper wire (diameter < 0.05 mm). The copper wire obtained [...] Read more.

The Ohon Continuous Casting is the main method for preparing single crystal copper wire, and it is also the research hotspot at present, but it is difficult to directly cast ultrafine single crystal copper wire (diameter < 0.05 mm). The copper wire obtained by continuous casting must be drawn and deformed before it can be used in practice, but this will bring a series of problems such as single crystal structure destruction and conductivity deterioration. Directional heat treatment technology can control the direction of heat flow at a low temperature, realize the directional migration of grain boundaries in the recrystallization process, and form columnar crystals or single crystals, which is of great significance for improving electrical conductivity. In this paper, the directional heat treatment method was used to investigate the microstructure evolution and influencing factors of pure copper wire, the process parameters were optimized, and the conductivity of pure copper wire was measured. It was found that the conductivity of pure copper wire increased by 5% when the heating temperature was 750 °C and the withdrawing velocity was 15 μm/s, which laid a foundation for the improvement of conductivity of pure copper wire. Full article

(This article belongs to the Section Crystalline Metals and Alloys)

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17 pages, 11796 KB

Open AccessArticle

Mineralogical, Gemological Characteristics and Petrogenesis of High-Quality Maw-Sit-Sit Jade from the Myanmar Jade Belt

by Yu Zhang, Guanghai Shi and Jiabao Wen

Crystals 2025, 15(11), 983; https://doi.org/10.3390/cryst15110983 - 14 Nov 2025

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Abstract

Maw-sit-sit jade resembles kosmochlor-jadeitite in appearance and is spatially associated with it in the Myanmar Jade Belt. However, the mineral composition, microstructure, and petrogenesis of this type of jade remain unclear. To address this gap, this study investigated high-quality Maw-sit-sit jade using a [...] Read more.

Maw-sit-sit jade resembles kosmochlor-jadeitite in appearance and is spatially associated with it in the Myanmar Jade Belt. However, the mineral composition, microstructure, and petrogenesis of this type of jade remain unclear. To address this gap, this study investigated high-quality Maw-sit-sit jade using a range of analytical techniques, including conventional gemological tests, infrared spectroscopy, petrographic observations, electron probe microanalysis (EPMA), and backscattered electron (BSE) imaging. Results show that Maw-sit-sit jade primarily consists of albite and chromium-omphacite, with minor amphibole (eckermannite and richterite). Jadeite and relict chromite are absent in the studied samples. Its high albite content gives it lower refractive index (RI: 1.55–1.56) and specific gravity (SG: 2.69–2.73) compared to kosmochlor-jadeitite and jadeite jade. Additionally, Maw-sit-sit jade exhibits punctate or banded fluorescence under ultraviolet (UV) light, distinguishing it from kosmochlor-jadeitite and jadeite jade (both inert). Petrographically, euhedral albite fills interstices between early-formed Cr-omphacite and eckermannite, which is textural evidence of its late-stage origin. Eckermannite and Cr-omphacite occur as enclosed grains with embayed boundaries and dissolution pores, indicating they experienced mechanical disruption and chemical dissolution during subsequent geological processes. Petrogenetically, Maw-sit-sit jade (defined as “Cr-omphacite-albitite”) forms via a two-stage process: (1) Under high-pressure/low-temperature (HP/LT) conditions in the subduction zone, Na-Al-Si-rich fluids metasomatize chromite-bearing serpentinite protoliths, generating an early assemblage of jadeite, Cr-omphacite and amphiboles; (2) During subsequent plate exhumation and decompression, jadeite underwent retrograde metamorphism under low-pressure/low-temperature (LP/LT) conditions involving residual Na-Al-Si fluids, resulting in the formation of albite. This process led to the replacement of early-formed minerals by euhedral albite, ultimately generating the Ab+Cr-Omp+Eck symplectic texture. This study elucidates the mineralogical, gemological identity and petrogenesis of high-quality Maw-sit-sit jade, advancing our understanding of fluid evolution within a subduction zone. Full article

(This article belongs to the Section Mineralogical Crystallography and Biomineralization)

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17 pages, 3178 KB

Open AccessArticle

Laser-Synthesized Plasmono-Fluorescent Si-Au and SiC-Au Nanocomposites for Colorimetric Sensing

by Yury V. Ryabchikov

Crystals 2025, 15(11), 982; https://doi.org/10.3390/cryst15110982 - 14 Nov 2025

Viewed by 513

Abstract

Sensing represents one of the most rapidly developing areas of modern life sciences, spreading from the detection of pathogenic microorganisms in living systems, food, and beverages to hazardous substances in liquid and gaseous environments. However, the development of efficient and low-cost multimodal sensors [...] Read more.

Sensing represents one of the most rapidly developing areas of modern life sciences, spreading from the detection of pathogenic microorganisms in living systems, food, and beverages to hazardous substances in liquid and gaseous environments. However, the development of efficient and low-cost multimodal sensors with easy-to-read functionality is still very challenging. In this paper, stable aqueous colloidal suspensions (ζ-potential was between −30 and −40 mV) of ultrasmall (~7 nm) plasmonic Si-Au and SiC-Au nanocomposites were formed. Two variants of pulsed laser ablation in liquids (PLAL)—direct ablation and laser co-fragmentation—were used for this purpose. The co-fragmentation approach led to a considerable decrease in hydrodynamic diameter (~78 nm) and bandgap widening to approximately 1.6 eV. All plasmonic nanocomposites exhibited efficient multi-band blue emission peaking at ~430 nm upon Xe lamp excitation. Co-fragmentation route considerably (~1 order of magnitude) increased the PL efficiency of the nanocomposites in comparison with the laser-ablated ones, accompanied by a negligible amount of dangling bonds. These silicon-based nanostructures significantly affected the optical response of rhodamine 6G, depending on the synthesis route. In particular, directly ablated nanoparticles revealed a stronger influence on the optical response of dye molecules. The observed findings suggest using such types of semiconductor-plasmonic nanocomposites for multimodal plasmonic and colorimetric sensing integrated with luminescent detection capability. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Multi-Component Hybrid and Composite Nanostructures)

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13 pages, 3064 KB

Open AccessArticle

Enhancement of Solidification Microstructure and Mechanical Properties of Al-5Si-Cu-Mg Alloy Through the Addition of Scandium and Zirconium

by Tian Li, Ling Shan, Chunwei Wang, JinHua Wu, Jianming Zheng and Kai Wang

Crystals 2025, 15(11), 981; https://doi.org/10.3390/cryst15110981 - 14 Nov 2025

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Abstract

Although low-silicon Al-Si alloys have been extensively studied, further improvement in their mechanical performance remains a critical challenge. This study examines the synergistic effects of scandium (Sc) and zirconium (Zr) additions on the solidification behavior, microstructural evolution, and mechanical properties of Al-5Si-Cu-Mg alloys. [...] Read more.

Although low-silicon Al-Si alloys have been extensively studied, further improvement in their mechanical performance remains a critical challenge. This study examines the synergistic effects of scandium (Sc) and zirconium (Zr) additions on the solidification behavior, microstructural evolution, and mechanical properties of Al-5Si-Cu-Mg alloys. The Sc/Zr additions refine the α-Al grains and modify the eutectic Si morphology, with the most uniform microstructure obtained at 0.5 wt.% due to the formation of coherent Al₃(Sc,Zr) dispersoids. These additions also suppress the formation of needle-like β-Al₅FeSi phases and promote the transformation to compact α-Al₁₅(Fe,Mn)₃(Si,Zr,Sc)₂ intermetallics, optimizing the solidification process. The yield strength increases with Sc/Zr content owing to grain-boundary and precipitation strengthening. However, the alloy without Sc/Zr exhibits the highest ultimate tensile strength and elongation, likely due to its finer secondary dendrite arm spacing and the absence of casting-induced cracks in this investigation. Although Sc/Zr additions of 0.25–0.5 wt.% contribute to microstructural refinement, the concurrent formation of porosity and coarse intermetallic compounds leads to a deterioration in ductility. Excessive Sc/Zr additions further coarsen grains and degrade the overall mechanical integrity. Full article

(This article belongs to the Special Issue Microstructure, Properties and Characterization of Aluminum Alloys)

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18 pages, 11078 KB

Open AccessArticle

Mechanism of Hydrothermal Zeolite Crystallization from Kaolin in Concentrated NaOH Solutions (1–5 M): Formation of NaP1, NaP2, Analcime, Sodalite and Cancrinite

by Paola Mameli, Ambra M. Fiore, Saverio Fiore and F. Javier Huertas

Crystals 2025, 15(11), 980; https://doi.org/10.3390/cryst15110980 - 14 Nov 2025

Viewed by 531

Abstract

Kaolin from the Donigazza deposit (NW Sardinia, Italy) was used to investigate the mechanisms of zeolite crystallization under alkaline hydrothermal conditions. The starting material, composed mainly of kaolinite and opal-CT with minor quartz and low iron content, was reacted with NaOH solutions (1–5 [...] Read more.

Kaolin from the Donigazza deposit (NW Sardinia, Italy) was used to investigate the mechanisms of zeolite crystallization under alkaline hydrothermal conditions. The starting material, composed mainly of kaolinite and opal-CT with minor quartz and low iron content, was reacted with NaOH solutions (1–5 mol L⁻¹) at 100 °C for 12–168 h. XRD analyses revealed the formation of zeolitic and related phases, including NaP1, NaP2, analcime, sodalite, and cancrinite, with zeolite contents reaching up to 100%. The extent of kaolinite dissolution varied with both NaOH concentration and reaction time, with complete transformation occurring at ≥3 mol L⁻¹ and ≥48 h. SEM imaging showed idiomorphic crystals (100 nm–10 μm) and globular nanoparticles (<50 nm), likely Na-Al-Si gels. Phase distribution reflected evolving solution chemistry, particularly changes in the Si/Al ratio due to differential dissolution of opal-CT and kaolinite. Crystallization proceeded via both classical (monomer addition) and non-classical (particle attachment) pathways, influenced by supersaturation, gel composition, and reaction kinetics. The transition from NaP1 to NaP2, and the development of metastable phases, indicate kinetic control consistent with Ostwald’s step rule. These results provide insights into the complex dynamics of zeolite formation from natural aluminosilicate precursors in alkaline environments. Full article

(This article belongs to the Special Issue Crystal Structure and Characterization of Minerals and Related Nanomaterials)

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19 pages, 4749 KB

Open AccessArticle

Modeling Fatigue Crack Growth Under Compressive Loads: The Role of Non-Monotonic Stress and Crack Closure

by Yahya Ali Fageehi and Abdulnaser M. Alshoaibi

Crystals 2025, 15(11), 979; https://doi.org/10.3390/cryst15110979 - 14 Nov 2025

Viewed by 461

Abstract

A comprehensive numerical investigation of Fatigue Crack Growth (FCG) under negative stress ratios (R < 0) was conducted using the Finite Element Method (FEM) and the ANSYS Benchmark 19.2 SMART crack growth module on modified Compact Tension (CT) specimens. This study addresses [...] Read more.

A comprehensive numerical investigation of Fatigue Crack Growth (FCG) under negative stress ratios (R < 0) was conducted using the Finite Element Method (FEM) and the ANSYS Benchmark 19.2 SMART crack growth module on modified Compact Tension (CT) specimens. This study addresses the critical challenge posed by the compressive portion of cyclic loading, which traditional Linear Elastic Fracture Mechanics (LEFM) models often fail to capture accurately due to the complex interaction of crack closure and reversed plastic zones. The analysis focused on the evolution of the von Mises stress and maximum principal stress distributions at the crack tip across a range of stress ratios, including R = 0.1, −0.1, −0.2, −0.3, −0.4, −0.5, and −1.0. The results demonstrate a significant inverse correlation between fatigue life cycles and the magnitude of the negative stress ratio, consistent with the detrimental effect of increasing tensile stress. Crucially, the numerical simulation successfully captured the non-monotonic behavior of the crack tip stress field, revealing that the compressive load phase substantially alters the effective stress intensity factor range and the crack growth path, which was governed by the Maximum Tangential Stress (MTS) criterion. This research provides a validated computational methodology for accurately predicting FCG life in engineering components subjected to demanding, fully reversed, or compressive–dominant cyclic loading environments. Full article

(This article belongs to the Special Issue Fatigue and Fracture of Crystalline Metal Structures)

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21 pages, 3742 KB

Open AccessArticle

Stability of Higher-Order Skyrmion Crystals Under Competing Magnetic Anisotropies in D_3d Systems

by Satoru Hayami

Crystals 2025, 15(11), 978; https://doi.org/10.3390/cryst15110978 - 13 Nov 2025

Viewed by 516

Abstract

We investigate the stability of higher-order skyrmion crystals with large topological charges in the presence of crystal-dependent magnetic anisotropies. Focusing on the competition between two types of bond-dependent anisotropy allowed by

D_{3 d}

crystalline symmetry on a two-dimensional triangular lattice, we systematically [...] Read more.

We investigate the stability of higher-order skyrmion crystals with large topological charges in the presence of crystal-dependent magnetic anisotropies. Focusing on the competition between two types of bond-dependent anisotropy allowed by

D_{3 d}

crystalline symmetry on a two-dimensional triangular lattice, we systematically construct a low-temperature magnetic phase diagram using simulated annealing. Our analysis reveals that the stability of the higher-order skyrmion crystal with skyrmion number of two is strongly controlled by the relative sign of the bond-dependent anisotropy to the

D_{3 d}

-type anisotropy: a positive anisotropy, which favors spin oscillations perpendicular to the ordering wave vector, enhances its stability, whereas a negative anisotropy, favoring oscillations parallel to the ordering wave vector, suppresses it and instead stabilizes a topologically trivial double-Q state. We further examine the field evolution of these phases under an out-of-plane magnetic field and show that distinct types of skyrmion crystals with the skyrmion number of one emerge in the intermediate-field regime. These results highlight that the competition between different magnetic anisotropies in crystalline systems is a key factor governing the stability of both zero-field and field-induced skyrmion crystals. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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16 pages, 20222 KB

Open AccessArticle

Resulted Mechanical and Microstructural Properties of Ballistic Protection Materials for Bulletproof Vest Applications Using Plasma Jet Thermal Spray Coatings

by Adrian Ioan Ropotoae, Corneliu Munteanu, Fabian Cezar Lupu, Bogdan Istrate, Marcelin Benchea, Adrian Nicolae Rotariu and Andrei Spoiala

Crystals 2025, 15(11), 977; https://doi.org/10.3390/cryst15110977 - 13 Nov 2025

Viewed by 296

Abstract

This paper addresses ballistic protection, which is an important element in the performance of any military equipment. Improving ballistic properties is a necessity for individual protection through the use of protective vests. In this study, plasma jet thermal deposition was performed on ballistic [...] Read more.

This paper addresses ballistic protection, which is an important element in the performance of any military equipment. Improving ballistic properties is a necessity for individual protection through the use of protective vests. In this study, plasma jet thermal deposition was performed on ballistic protection materials, steel plates from the ARMOX category, using both metallic and ceramic powders. The samples with appropriate dimensions, covered with these types of powders, were analyzed from a microstructural point of view to determine their mechanical properties and evaluate the improvement in ballistic protection level. Microstructural analyses by optical and electronic microscopy, SEM (Scanning Electron Microscopy), allowed the performance of complex analyses regarding the adhesion of the deposits to the base material. It was possible to evaluate the microstructure, thickness, uniformity, and porosity of the deposits and the microstructural aspects at the interface between the base material and the deposit. For the efficient use of these deposits, tribological studies were carried out on the mechanical properties through scratch and microindentation analyses. The paper concludes the results obtained for the two types of deposits, metallic and ceramic, to streamline their use to increase the ballistic protection of bulletproof vests used in individual protection in military equipment. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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15 pages, 4474 KB

Open AccessArticle

Spectroscopic Study of Electrolytic-Plasma Discharge During Hardening of 20GL Steel and Its Effect on Microstructure and Mechanical Properties

by Bauyrzhan Rakhadilov, Rinat Kurmangaliyev, Nurlat Kadyrbolat, Rinat Kussainov, Zarina Satbayeva, Almasbek Maulit and Yerzhan Shayakhmetov

Crystals 2025, 15(11), 976; https://doi.org/10.3390/cryst15110976 - 13 Nov 2025

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Abstract

This study investigated the electrolytic-plasma hardening (EPH) of cast 20GL steel, used for railway spring beams. The main objective was to analyze the spectral characteristics of the cathodic discharge and establish correlations between the plasma parameters, processing regimes, and resulting surface properties. Optical [...] Read more.

This study investigated the electrolytic-plasma hardening (EPH) of cast 20GL steel, used for railway spring beams. The main objective was to analyze the spectral characteristics of the cathodic discharge and establish correlations between the plasma parameters, processing regimes, and resulting surface properties. Optical emission spectroscopy revealed that the plasma at 260 V exhibited a high-energy state with an electron density of ~5.3 × 10¹⁶ cm⁻³ and an electron temperature of 10,031 K. Using these parameters, the heat flux from the plasma to the steel surface was estimated at ~1.5 × 10⁷ W/m², confirming that the discharge provides sufficient energy for surface austenitization. Microstructural analysis demonstrated that the electrolyte flow rate, which determines the cooling rate, is the key parameter controlling phase transformations. At low flow rates, ferrite–pearlite and bainitic structures formed, while a fully martensitic structure and maximum hardness (1046 HV) were achieved at 10 L/min. Tribological tests confirmed the superior wear resistance of the martensitic layers, showing a friction coefficient of 0.454 and a wear volume 3.4 times lower than in the as-cast state. These findings verify that EPH offers an energy-efficient, low-cost method for improving the surface performance and service life of 20GL steel components in heavy-duty railway applications. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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30 pages, 8504 KB

Open AccessArticle

Comparative Analysis of Single-Particle Radiation Sensitivity of AlN, Diamond and β-Ga₂O₃ Semiconductors Exposed to Terrestrial Sea Level Neutrons

by Daniela Munteanu and Jean-Luc Autran

Crystals 2025, 15(11), 975; https://doi.org/10.3390/cryst15110975 - 12 Nov 2025

Viewed by 216

Abstract

Aluminum nitride (AlN), diamond, and β-phase gallium oxide (β-Ga₂O₃) belong to the family of ultra-wide bandgap (UWBG) semiconductors and exhibit remarkable properties for future power and optoelectronic applications. Compared to conventional wide bandgap (WBG) materials such as silicon carbide [...] Read more.

Aluminum nitride (AlN), diamond, and β-phase gallium oxide (β-Ga₂O₃) belong to the family of ultra-wide bandgap (UWBG) semiconductors and exhibit remarkable properties for future power and optoelectronic applications. Compared to conventional wide bandgap (WBG) materials such as silicon carbide (SiC) and gallium nitride (GaN), they demonstrate clear advantages in terms of high-voltage, high-temperature, and high-frequency operation, as well as extremely high breakdown fields. In this work, numerical simulations are performed to evaluate and compare the radiative responses of AlN, diamond, and β-Ga₂O₃ when exposed to neutron irradiation covering the full atmospheric spectrum at sea level, from 1 meV to 10 GeV. The Geant4 simulation framework is used to model neutron interactions with the three materials, focusing on single-particle events that may be triggered. A detailed comparison is conducted, particularly concerning the generation of secondary charged particles and their distributions in energy, linear energy transfer (LET), and range given by SRIM. The contribution of the ¹⁴N(n,p)¹⁴C reaction in AlN is also specifically investigated. In addition, the study examines the consequences of these interactions in terms of electron-hole pair generation and charge deposition, and discusses the implications for the radiation sensitivity of these materials when exposed to atmospheric neutrons. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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29 pages, 4413 KB

Open AccessArticle

Reactions of the Uranyl Ion and a Bulky Tetradentate, “Salen-Type” Schiff Base: Synthesis and Study of Two Mononuclear Complexes

by Sotiris G. Skiadas, Ioanna Th. Papageorgiou, Zoi G. Lada, Catherine P. Raptopoulou, Vlasoula Bekiari, Vassilis Psycharis, Sokratis T. Tsantis and Spyros P. Perlepes

Crystals 2025, 15(11), 974; https://doi.org/10.3390/cryst15110974 - 12 Nov 2025

Viewed by 276

Abstract

The reactions of UO₂(NO₃)₂·6H₂O or UO₂(O₂CMe)₂·2H₂O and 2,2′-{(1,2-ethanediyl)bis[nitrilo(phenyl)methylidene]}bisphenol (H₂L) in MeOH and DMF have provided access to complexes [UO₂(L)(MeOH)] (1) and [...] Read more.

The reactions of UO₂(NO₃)₂·6H₂O or UO₂(O₂CMe)₂·2H₂O and 2,2′-{(1,2-ethanediyl)bis[nitrilo(phenyl)methylidene]}bisphenol (H₂L) in MeOH and DMF have provided access to complexes [UO₂(L)(MeOH)] (1) and [UO₂(L)(DMF)]·DMF (2·DMF), respectively. The molecular structures of the complexes are similar. The central U^VI atom is surrounded by five oxygen and two nitrogen atoms in a distorted pentagonal bipyramidal geometry; the two uranyl oxygen atoms are at the axial positions. Two phenolato oxygen and two imino nitrogen atoms from the tetradentate chelating (1.1111 using Harris notation) L²⁻ ligand are located at the equatorial plane, which is completed by the oxygen atom of a terminally ligated solvent (MeOH, DMF) molecule. Interestingly, the L²⁻ ligand adopts a chair (or stepped) conformation in 1 and a boat conformation in 2·DMF. The supramolecular features of 1 and 2·DMF are distinctly different due to the different H-bonding abilities of coordinated MeOH and DMF, and the presence of an extra-lattice solvent molecule in the latter. The solid complexes were studied by IR, Raman, electronic (UV/Vis), and emission spectroscopic techniques. Complex 1 decomposes in CHCl₃ and DMSO, whereas the molecular structure of 2 is retained in these solvents. A new polymorph of the free ligand, H₂L(B), has also been discovered and its crystal structure is described. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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23 pages, 38358 KB

Open AccessArticle

Microstructure and Mechanical Properties of Hybrid Pure Al/B₄C/Microsilica Composites Produced by Ultrasonically Assisted Stir Casting

by Maxat Abishkenov, Ilgar Tavshanov, Kairosh Nogayev, Zoja Gelmanova, Saule Kamarova and Almas Yerzhanov

Crystals 2025, 15(11), 973; https://doi.org/10.3390/cryst15110973 - 12 Nov 2025

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Abstract

This study explores the fabrication and characterization of hybrid aluminum matrix composites reinforced with boron carbide (B₄C) and microsilica, produced via ultrasonically assisted stir casting followed by T6 heat treatment. Pure aluminum was selected as the base matrix to evaluate the [...] Read more.

This study explores the fabrication and characterization of hybrid aluminum matrix composites reinforced with boron carbide (B₄C) and microsilica, produced via ultrasonically assisted stir casting followed by T6 heat treatment. Pure aluminum was selected as the base matrix to evaluate the combined effects of B₄C and microsilica reinforcements. Microstructural analyses showed that ultrasonic treatment effectively dispersed nanoparticles, reduced agglomeration, and enhanced particle–matrix interfacial bonding. T6 heat treatment further refined the grain structure through Zener pinning and promoted the formation of reaction layers at particle interfaces. Mechanical testing revealed that Al/B₄C composites provided the highest strength and hardness, while Al/microsilica systems retained superior ductility. The hybrid Al/B₄C/microsilica composites demonstrated a balanced combination of yield strength (38.6 MPa), ultimate tensile strength (82.6 MPa), and elongation (35.2%), confirming a synergistic strengthening–toughening effect. These results highlight the potential of Al/B₄C/microsilica hybrid reinforcements to optimize the trade-off between strength and ductility in aluminum-based composites. Full article

(This article belongs to the Section Hybrid and Composite Crystalline Materials)

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