Materials

12 pages, 1994 KB

Open AccessArticle

Construction of Graphite Shells on Ferromanganese Oxide for Electromagnetic Wave Absorption

by Yuxiang Zhang, Shuling Shen and Jing Li

Materials 2025, 18(23), 5336; https://doi.org/10.3390/ma18235336 - 26 Nov 2025

Ferromanganese oxide (FMO), a by-product of steelmaking industry, was coated with polyacrylonitrile (PAN) to construct an electromagnetic wave absorber (FMO@C) with a core–shell structure. The effect of heat treatment from 600 to 1000 °C on the phase transformation of FMO and carbonization of [...] Read more.

Ferromanganese oxide (FMO), a by-product of steelmaking industry, was coated with polyacrylonitrile (PAN) to construct an electromagnetic wave absorber (FMO@C) with a core–shell structure. The effect of heat treatment from 600 to 1000 °C on the phase transformation of FMO and carbonization of PAN was studied. Upon the heat treatment at 1000 °C, the reflection loss and effective bandwidth of the FMO@C reached −18.20 dB and 3.08 GHz at a thickness of 1.6 mm, presenting a significant improvement over FMO which only exhibited a reflection loss of −2.31 dB at 10 mm. Boric acid was infiltrated into the PAN shells to catalyze the carbonization process and adjust the impedance matching, which further improved the reflection loss to a minimum value of −28.25 dB. Via varying the concentration of boric acid, the reflection loss of −22.01 dB with an effective bandwidth of 3.36 GHz at a thickness of 1.3 mm was achieved. The enhanced EMW absorption performance was attributed to multiple reflections and polarization caused by the core–shell structure, magnetic loss from the phase transformation of FMO, dielectric loss from carbon shells, as well as the tunable impedance matching by boron-catalyzed carbonization. The construction of the core–shell structure could be a promising downstream processing of FMO and could extend the application of the solid wastes. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Diverse Applications—Second Edition)

14 pages, 3124 KB

Open AccessArticle

Mechanism by Which Heat Treatment Influences the Acoustic Vibration Characteristics of Bamboo

by Rongzhen Song, Ying Li, Shanyu Han, Lei Chen, Shumin Yang, Genlin Tian, Xing’e Liu, Fuming Chen and Zehui Jiang

Materials 2025, 18(23), 5335; https://doi.org/10.3390/ma18235335 (registering DOI) - 26 Nov 2025

Abstract

The multi-layered and multi-scale refined structure of bamboo gives bamboo musical instruments a unique tonal quality. This study employed heat treatment to enhance the acoustic vibration stability of bamboo materials. The hammering method was subsequently employed for conducting multi-point impact excitation tests on [...] Read more.

The multi-layered and multi-scale refined structure of bamboo gives bamboo musical instruments a unique tonal quality. This study employed heat treatment to enhance the acoustic vibration stability of bamboo materials. The hammering method was subsequently employed for conducting multi-point impact excitation tests on instrument-grade bamboo, and the resulting vibration response was subjected to modal analysis. Next, we investigated the acoustic vibration characteristics of bamboo, including its sound vibration efficiency, timbre, and acoustic stability, in terms of its macroscopic gradient structure, ultra-microstructure, molecular scale, key components, and pore structure. Modal analysis revealed that the first three damping ratios of Xipi were 94.55%, 7.89%, and 26.60% higher than those of Erhuang, respectively. The relative stiffness of Xipi across the first three modes was 1.22, 1.22, and 1.18 times that of Erhuang, indicating a generally higher structural rigidity. The first three natural frequencies of Xipi were approximately 1.20, 1.20, and 1.19 times higher than those of Erhuang, and its fundamental transfer function value was 1.5 times greater, suggesting a lower susceptibility to low-frequency resonance. Modal shapes showed distinct vibration behaviors between the two types: Xipi exhibited a more effective energy transmission path in the second mode and less structural distortion in the third mode, potentially indicating higher structural integrity. This research provides support for developing new technologies to select and process bamboo materials for musical instruments. Full article

16 pages, 1465 KB

Open AccessArticle

High-Frequency Plasma Electrolytic Oxidation of an Al–Si Alloy: Influence of Al₂O₃ and SiO₂ Additives on Coating Microstructure and Tribological Performance

by Gulzhaz Uazyrkhanova, Amangeldi Sagidugumar, Yernat Kozhakhmetov, Gulzhaz Moldabayeva, Daniyar Kaliyev, Sergey Rudenko and Nurgamit Kantay

Materials 2025, 18(23), 5334; https://doi.org/10.3390/ma18235334 - 26 Nov 2025

Abstract

This study focuses on surface modification of aluminum alloys (Al–Si) with high silicon content using plasma electrolytic oxidation (PEO). The influence of Al₂O₃ and SiO₂ particles, introduced both separately and in combination, into a sodium aluminate-based electrolyte during high-frequency [...] Read more.

This study focuses on surface modification of aluminum alloys (Al–Si) with high silicon content using plasma electrolytic oxidation (PEO). The influence of Al₂O₃ and SiO₂ particles, introduced both separately and in combination, into a sodium aluminate-based electrolyte during high-frequency treatment (2000 Hz). Examination of surface and cross-sections using a scanning electron microscope SEM showed an increase in the compactness of the coating when Al₂O₃ particles were introduced. The addition of SiO₂ particles tended to promote a smoother surface and a slight reduction in the porosity and defect density. However, when these particles are added together, especially at high concentrations, an increase in structural defects and crack formation is observed. X-ray diffraction analysis revealed that the γ-Al₂O₃ phase was present in all coatings. In the samples with Al₂O₃ addition, the α-Al₂O₃ diffraction signal became stronger compared with the other coatings. Tribological tests revealed that the addition of Al₂O₃ particles significantly improved wear resistance, while the introduction of SiO₂ particles contributed to the stabilization of the friction coefficient. Thus, Al₂O₃ particles were the most effective in enhancing the mechanical properties of the coating. Full article

(This article belongs to the Section Thin Films and Interfaces)

18 pages, 4465 KB

Open AccessArticle

Influence of Film Thickness on the Structure and Properties of Copper Thin Films Deposited on BaTiO₃ Ceramics by DCMS and HiPIMS

by Yuanhao Liao, Heda Bai, Fengtian Shi, Jin Li and Xiangli Liu

Materials 2025, 18(23), 5333; https://doi.org/10.3390/ma18235333 - 26 Nov 2025

Abstract

In this study, we investigate the role of film thickness in modulating the properties of Cu films deposited on BaTiO₃ ceramic substrates using direct current magnetron sputtering (DCMS) and high-power pulsed magnetron sputtering (HiPIMS). While HiPIMS is known for producing dense films, [...] Read more.

In this study, we investigate the role of film thickness in modulating the properties of Cu films deposited on BaTiO₃ ceramic substrates using direct current magnetron sputtering (DCMS) and high-power pulsed magnetron sputtering (HiPIMS). While HiPIMS is known for producing dense films, and the thickness-dependent properties of sputtered Cu films are well-documented, this work uniquely explores the synergistic interplay between deposition technique and thickness on BaTiO₃ ceramic substrates, revealing novel insights into stress evolution and property optimization for advanced microelectronic and coating applications. Cu films of 300 nm, 1000 nm, and 1700 nm were systematically compared for their microstructures, surface morphologies, and electrical and mechanical properties, elucidating the critical role of thickness in densification, stress state, and overall performance. The results indicate that the target current and voltage waveforms of HiPIMS are similar to square waves, and the ionization rate is significantly higher than that of DCMS. Still, the deposition rate at the same power of 180 W is only 44.6% of that of DCMS. The films obtained by both processes present a strong (111) orientation; the crystallite size of the DCMS film grows with increasing thickness, while the HiPIMS film shows increasing and then decreasing, and its residual stress is overall lower than that of DCMS. In terms of surface morphology, DCMS films appeared porous and rough, whereas HiPIMS films were denser and smoother. In terms of properties, the resistivity of HiPIMS films is significantly lower than that of DCMS, especially at 1000 nm thickness. The binding force is also better than that of DCMS, especially at thicknesses less than 1000 nm, which is mainly attributed to the compressive stresses introduced by the energetic ion bombardment at the early deposition stage. These findings provide new mechanistic insights into thickness-dependent stress and property modulation, offering a reference for tailoring high-performance Cu films through process optimization. Full article

(This article belongs to the Special Issue Advanced Thin Films: Structural, Optical, and Electrical Properties)

37 pages, 6455 KB

Open AccessArticle

Experimental Investigation on the Bending Performance of Steel–Concrete Composite Beams After Creep

by Faxing Ding, Yang Dai, Xiaolei He, Fei Lyu and Linli Duan

Materials 2025, 18(23), 5332; https://doi.org/10.3390/ma18235332 - 26 Nov 2025

Abstract

The long-term flexural performance of steel-concrete composite beams after creep is influenced by multiple factors such as the degree of shear connection, cross-sectional form, and boundary conditions. The engineering community has an ambiguous understanding of the coupling effects of these factors. To address [...] Read more.

The long-term flexural performance of steel-concrete composite beams after creep is influenced by multiple factors such as the degree of shear connection, cross-sectional form, and boundary conditions. The engineering community has an ambiguous understanding of the coupling effects of these factors. To address this issue, this paper conducts systematic experimental research: six simply supported beams (three box-shaped, three I-shaped) and four continuous beams (two box-shaped, two I-shaped) were designed with three degrees of shear connection (0.57, 1.08, 1.53). These beams first underwent simulated creep tests (24 °C, 80% relative humidity, 10 kN load, 180 days), followed by monotonic bending tests. The results indicate: (1) A high degree of shear connection (1.53) reduces creep deflection by 15–20% compared to partial connection (0.57) and delays the initiation of interface slip to 30% of the ultimate load; (2) Box sections exhibit 10–15% lower creep deflection than I-sections, though both experience 40–60% stiffness reduction after creep; (3) Continuous beams show a 25% improvement in crack resistance in the negative moment region and a 50% increase in flexural capacity at mid-span compared to simply supported beams; (4) After creep, the elastic modulus of concrete decreases by 40–60% (inversely related to the degree of shear connection), with fully connected specimens retaining 55–61% of their strength, while partially connected specimens retain only 43–49%. This study quantifies the degradation patterns of concrete performance, clarifies the influence mechanisms of key structural factors, and provides theoretical and experimental support for the long-term performance design of composite beams. Shear connection design is crucial for mitigating creep effects. Full article

(This article belongs to the Section Construction and Building Materials)

16 pages, 10674 KB

Open AccessArticle

Mechanisms Influencing Ferromagnetic Resonance Linewidth in Ca–In–Sn Co-Substituted Yttrium–Iron Garnet Ferrites

by Yiwei Hu, Xiansong Liu and Shuangjiu Feng

Materials 2025, 18(23), 5331; https://doi.org/10.3390/ma18235331 - 26 Nov 2025

Abstract

With the rapid development of communication technologies such as 5G, yttrium iron garnet (YIG) has been widely applied in microwave devices and other systems owing to its low ferromagnetic resonance linewidth. Loss reduction and effects of doping on performance have been important research [...] Read more.

With the rapid development of communication technologies such as 5G, yttrium iron garnet (YIG) has been widely applied in microwave devices and other systems owing to its low ferromagnetic resonance linewidth. Loss reduction and effects of doping on performance have been important research areas for garnet ferrite. This study prepared Ca²⁺, In³⁺, and Sn⁴⁺ codoped YIG ferrite samples with the chemical formula Y_3−xCa_xFe_5−x−yIn_ySn_xO₁₂ (x = 0.05–0.3) (y = 0.2, 0.45) via solid-state reaction. The analyses of the crystal structure, micromorphology, and magnetic properties enabled the identification of the causes of variations in parameters, such as saturation magnetization and coercivity. Theoretical calculations of the anisotropy constants clarified the patterns upon substituting Fe³⁺ with In³⁺ and Sn⁴⁺, revealing a shift in the positions of Fe³⁺ substitution. Finally, the primary factors influencing loss were identified, and the key process parameters influencing performance were determined. The resulting polycrystalline garnet ferrite exhibited an extremely low ferromagnetic resonance linewidth parameter (ΔH = 29 Oe) and a high density (>5.2 g/cm³). This study provides specific guidance on process parameters and element selection for high-performance, low-loss YIG materials, as well as a detailed theoretical explanation of the performance changes resulting from co-doping YIG with In³⁺ and Sn⁴⁺. Full article

(This article belongs to the Section Metals and Alloys)

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4 pages, 149 KB

Open AccessEditorial

An Editorial for Mechanical Performance and Microstructural Characterization of Light Alloys (2nd Edition)

by Qinghuan Huo

Materials 2025, 18(23), 5330; https://doi.org/10.3390/ma18235330 - 26 Nov 2025

Abstract

Although studies on the mechanical performance of light metals and their alloys have been carried out all over the world [...] Full article

(This article belongs to the Special Issue Mechanical Performance and Microstructural Characterization of Light Alloys (2nd Edition))

20 pages, 3351 KB

Open AccessArticle

Preliminary Study of Microbial Corrosion of Stainless Steel AISI 304 Under Conditions Simulating Deep Radioactive Waste Disposal

by Elena Abramova, Oleg Tripachev, Natalia Shapagina and Alexey Safonov

Materials 2025, 18(23), 5329; https://doi.org/10.3390/ma18235329 - 26 Nov 2025

Abstract

This work involved the laboratory modeling of biogenic and biogenically mediated corrosion of AISI 304 stainless steel under geochemical conditions representative of the geological disposal of radioactive waste at the Yeniseisky site (Russia). Experiments with a single glucose stimulation of a microbial community [...] Read more.

This work involved the laboratory modeling of biogenic and biogenically mediated corrosion of AISI 304 stainless steel under geochemical conditions representative of the geological disposal of radioactive waste at the Yeniseisky site (Russia). Experiments with a single glucose stimulation of a microbial community sampled from a depth of 450 m established that the initial dominance of organotrophic microflora (primarily genera such as Xanthobacterium, Novosphingobium, Hydrogenophaga, and Pseudomonas) during the first stage (up to 30 days) led to the formation of a microbial biofilm. This biofilm resulted in uniform surface corrosion at a rate of up to 16 µm/year, which is more than 30 times higher than the corrosion rate in the abiotic control. This acceleration is attributed to the accumulation of microbial metabolites, including acetate, ethanol, formate, succinate, n-butyrate, and lactate. The subsequent development of chemotrophic iron- and sulfur-cycling microflora (dominated by genera such as Sideroxydans, Pseudomonas, Geobacter, Desulfuromonas, Desulfovibrio, and Desulfomicrobium) during the second stage of microbial succession (days 60–120) led to the formation of a pit density 10 times greater than that in the abiotic control. It is important to note that the maximum corrosion rates and pit densities were observed upon the addition of a mixture of glucose and sulfate. An assessment of the role of various microbial metabolites and medium components using the potentiodynamic method demonstrated that the combined presence of hydrocarbonate, sulfide, and microbial metabolites in the solution caused a more than fivefold increase in the corrosion current. Thus, the results demonstrate the complex nature of corrosion processes under conditions modeling the geological disposal of radioactive waste, where biological and abiotic factors interact, creating a synergistic effect that significantly enhances corrosion. Full article

(This article belongs to the Section Corrosion)

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20 pages, 1279 KB

Open AccessSystematic Review

Synthetic Biomaterials for Alveolar Bone Regeneration: A Systematic Review of Clinical Evidence

by Beatrice Bozza, Paolo Pesce, Domenico Baldi, Francesco Bagnasco, Marco Migliorati and Nicola De Angelis

Materials 2025, 18(23), 5328; https://doi.org/10.3390/ma18235328 - 26 Nov 2025

Abstract

Background: Alveolar bone resorption remains a major challenge in implant and prosthetic rehabilitation. While autologous bone grafts are still considered the gold standard, their biological and surgical limitations have promoted the use of synthetic biomaterials such as biphasic calcium phosphate (BCP), β-tricalcium phosphate [...] Read more.

Background: Alveolar bone resorption remains a major challenge in implant and prosthetic rehabilitation. While autologous bone grafts are still considered the gold standard, their biological and surgical limitations have promoted the use of synthetic biomaterials such as biphasic calcium phosphate (BCP), β-tricalcium phosphate (β-TCP), nanocrystalline hydroxyapatite, and bioactive glass. Methods: This systematic review, conducted in accordance with PRISMA guidelines, was based on a comprehensive search performed in March 2025 across PubMed, MEDLINE, Embase, and Google Scholar. A total of 11 clinical studies—including both randomized and non-randomized comparative trials—were identified. Due to the marked heterogeneity of study designs and outcome measures, meta-analysis was not feasible. Reported outcomes focused on bone volume preservation, residual biomaterial, implant stability, histological integration, and postoperative complications. Results: Overall, synthetic biomaterials achieved satisfactory bone regeneration and implant stability, with mean bone preservation ranging between 85% and 95%, often comparable to xenografts and other grafting materials. Among the materials analyzed, β-TCP and BCP generally demonstrated superior resorption control and dimensional stability, while bioactive glass showed favorable integration and remodeling rates. The addition of bioactive agents such as rhBMP-2, rhPDGF-BB, or platelet-rich plasma further enhanced new bone formation. Conclusions: Within the limits of current evidence, synthetic biomaterials show clinical performance comparable to xenografts, particularly in socket preservation and ridge augmentation procedures. Their predictable handling, absence of donor-site morbidity, and potential for bioactive enhancement make them valuable tools for routine clinical use. Larger, standardized trials with long-term follow-up are needed to validate these findings and refine material selection in alveolar bone regeneration. Full article

(This article belongs to the Special Issue Biomaterials in Periodontology and Implant Dentistry)

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18 pages, 8171 KB

Open AccessArticle

Experimental Study of the Discharging Process of Sorption Heat Storage Units Filled with 13X Zeolite

by Beata Pytlik, Daniel Smykowski, Piotr Szulc, Tomasz Tietze, Beata Anwajler and Artur Chorążyczewski

Materials 2025, 18(23), 5327; https://doi.org/10.3390/ma18235327 - 26 Nov 2025

Abstract

The paper presents the experimental study of the zeolite heat storage unit discharging process in a laboratory scale. The Authors focused on the discharging process, which utilizes adsorption of water, in the form of steam, on zeolite, because the adsorption process is considered [...] Read more.

The paper presents the experimental study of the zeolite heat storage unit discharging process in a laboratory scale. The Authors focused on the discharging process, which utilizes adsorption of water, in the form of steam, on zeolite, because the adsorption process is considered as more challenging in terms of reaction kinetics and heat transfer. The Authors designed and built a laboratory stand with a sorption heat storage unit filled with 13X zeolite and with a separated heat transfer fluid system, where air was used for discharging. Dynamic parameters including the temperature of inlet and outlet air and the temperature distribution inside the zeolite bed during the discharging process were investigated. The gathered measurement data were used to determine the heat fluxes and to compute dynamic heat balance of the thermal storage unit including internal and external heat losses. It was demonstrated that the applied design and scale of the thermal storage unit allows to reach the thermal power over 300 W and heat the discharging air from 40 °C to over 110 °C. The innovative aspect of the study is the improvement of operational stability of the sorption heat storage unit through the implementation of a heat exchanger design that separates the heat transfer fluid from the zeolite bed, as well as a control system with a neural network layer for predicting the mass flow rate of steam. Full article

(This article belongs to the Special Issue Research on Zeolites and Zeolite-Like Materials: Synthesis, Structure, Properties and Application)

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14 pages, 1567 KB

Open AccessArticle

Osteogenic Potential of Various Premixed Hydraulic Calcium Silicate-Based Sealers on Human Bone Marrow Stem Cells

by Na-Hyun You, Donghee Lee, Yemi Kim, Sieun Nam and Sin-Young Kim

Materials 2025, 18(23), 5326; https://doi.org/10.3390/ma18235326 - 26 Nov 2025

Abstract

This study aims to compare the osteogenic potential of premixed hydraulic calcium silicate-based sealers (HCSSs) with an epoxy resin-based sealer in human bone marrow-derived stem cells (hBMSCs). Three HCSSs (White Endoseal MTA, One-Fil, EndoSequence BC Sealer) were compared with AH Plus Jet, an [...] Read more.

This study aims to compare the osteogenic potential of premixed hydraulic calcium silicate-based sealers (HCSSs) with an epoxy resin-based sealer in human bone marrow-derived stem cells (hBMSCs). Three HCSSs (White Endoseal MTA, One-Fil, EndoSequence BC Sealer) were compared with AH Plus Jet, an epoxy resin-based sealer. Disk-shaped specimens were prepared using sterilized Teflon tubes and immersed in osteogenic medium to create eluates. hBMSCs were cultured in each eluate, and osteogenic potential was assessed by alkaline phosphatase (ALP) activity (n = 6), Alizarin Red-S (ARS) staining (n = 6), quantitative real-time polymerase chain reaction (qPCR) (n = 3), and Western blot analysis. Statistical analyses were conducted using SPSS (version 24.0), with significance set at p < 0.05. All experimental groups exhibited higher ALP activity than the control on day 4. ARS staining of HCSSs differed significantly from AH Plus Jet on day 14 (p < 0.05), while White Endoseal MTA exhibited the highest intensity. qPCR revealed that EndoSequence BC Sealer induced the highest SMAD1 expression on day 4, while One-Fil and EndoSequence BC Sealer significantly upregulated RUNX2 expression compared with AH Plus Jet (p < 0.05). Western blotting confirmed that EndoSequence BC Sealer induced the highest RUNX2 protein expression. Collectively, premixed HCSSs promoted superior mineralization and RUNX2 expression compared to conventional resin-based sealer in hBMSCs. Full article

(This article belongs to the Special Issue Development and Research of New Dental Materials)

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24 pages, 6903 KB

Open AccessArticle

Analysis of Load-Bearing Capacity and Lateral-Torsional Buckling (LTB) Stability of OSB Laminated and I-Beams Made of Wood and Wood-Based Materials

by Arkadiusz Denisiewicz, Tomasz Socha and Krzysztof Kula

Materials 2025, 18(23), 5325; https://doi.org/10.3390/ma18235325 - 26 Nov 2025

Abstract

The study presents experimental and numerical analyses comparing two types of wood-based structural beams—laminated beams made of oriented strand board (OSB) and traditional wooden I-beams. Load-bearing capacity, stiffness, and susceptibility to loss of stability were compared. Full-scale four-point bending tests were conducted on [...] Read more.

The study presents experimental and numerical analyses comparing two types of wood-based structural beams—laminated beams made of oriented strand board (OSB) and traditional wooden I-beams. Load-bearing capacity, stiffness, and susceptibility to loss of stability were compared. Full-scale four-point bending tests were conducted on 5400 mm-long beams with 300 mm cross-sectional height, in accordance with the European Organisation for Technical Approvals (EOTA) guidelines. The results showed that OSB laminated beams, despite having about 20% lower bending stiffness, achieved up to 46% higher ultimate load capacity compared to I-beams. Failures in I-beams were mainly initiated by material defects and weaknesses in the glued joints of flanges, whereas laminated beams exhibited more uniform and predictable behaviour with greater repeatability of results. Numerical simulations performed in Abaqus/Standard 2022, including linear buckling and modal analyses, confirmed the experimental findings and indicated higher global stability and dynamic stiffness of laminated beams. The numerical model was validated in the elastic range and subsequently used to assess stability and dynamic behaviour, which are governed by linear elastic stiffness. The obtained results demonstrate that OSB laminated beams can serve as a potential alternative to conventional I-beams in structural applications requiring high safety and durability, offering a structurally efficient and more failure-tolerant configuration. Full article

(This article belongs to the Section Construction and Building Materials)

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11 pages, 2169 KB

Open AccessCommunication

Robust Self-Trapped Exciton Emission in Sb³⁺-Engineered Lead-Free Cs₄SnBr₆ Zero-Dimensional Perovskites

by Haixia Wu, Wendi Zhou, Rui Huang, Jie Song, Zhenxu Lin, Yi Zhang, Tianpei Qiu and Hongliang Li

Materials 2025, 18(23), 5324; https://doi.org/10.3390/ma18235324 - 26 Nov 2025

Abstract

Zero-dimensional (0D) tin halide perovskites have emerged as promising luminescent materials owing to their broadband emission, high quantum yield, and negligible self-absorption. Yet, their luminescence efficiency and stability remain insufficient for practical optoelectronic applications. Here, Sb³⁺ dopants are introduced into Cs₄ [...] Read more.

Zero-dimensional (0D) tin halide perovskites have emerged as promising luminescent materials owing to their broadband emission, high quantum yield, and negligible self-absorption. Yet, their luminescence efficiency and stability remain insufficient for practical optoelectronic applications. Here, Sb³⁺ dopants are introduced into Cs₄SnBr₆ through a water-assisted wet ball milling strategy, resulting in bright and thermally robust emission. The doped materials exhibit pronounced self-trapped exciton (STE) luminescence centered at 525 nm with a broad full width at half maximum of 110 nm, a large Stokes shift of approximately ~1.3 eV, and a photoluminescence lifetime of ~0.8 µs. Remarkably, Sb³⁺ incorporation boosts the photoluminescence quantum yield (PLQY) up to 64% at room temperature while simultaneously improving thermal stability. Correlated spectroscopic analyses reveal that the Sb³⁺-induced lattice distortion of the [SnBr₆]⁴⁻ octahedra strengthens electron–phonon interactions and elevates the STE binding energy, thereby stabilizing the excited states and suppressing nonradiative losses. Full article

(This article belongs to the Special Issue Advances in Luminescent Materials: Fabrication and Technological Applications)

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17 pages, 4796 KB

Open AccessArticle

Nanomechanical and Adhesive Behavior of Electrophoretically Deposited Hydroxyapatite- and Chitosan-Based Coatings on Ti13Zr13Nb Alloy

by Michał Bartmański

Materials 2025, 18(23), 5323; https://doi.org/10.3390/ma18235323 - 26 Nov 2025

Abstract

This work reports on the effects of surface pre-treatment and EPD process parameters on the nanomechanical and adhesive performance of chitosan-based composite coatings fabricated on a Ti13Zr13Nb alloy. Three different coating systems were prepared: chitosan–Cu (series A), chitosan–HAp (series B), and HAp–Cu (series [...] Read more.

This work reports on the effects of surface pre-treatment and EPD process parameters on the nanomechanical and adhesive performance of chitosan-based composite coatings fabricated on a Ti13Zr13Nb alloy. Three different coating systems were prepared: chitosan–Cu (series A), chitosan–HAp (series B), and HAp–Cu (series C). Coatings were deposited from suspensions at different voltages (10–30 V) and for various times (1–2 min) onto polished, anodized, and laser surface-treated titanium alloy substrates. Microstructural, nanomechanical, and adhesion properties were characterized by means of SEM, nanoindentation, and nanoscratch testing, respectively. Chitosan–Cu coatings exhibited the highest hardness (up to 8.2 GPa) and stiffness due to the homogeneous dispersion of Cu nanoparticles and strong interfacial bonding to the underlying anodized TiO₂ layer. Chitosan–HAp coatings were softer (0.05–0.13 GPa) and highly plastic, particularly after laser surface treatment due to their specific porous, polymer-dominated structure. HAp–Cu coatings exhibited an intermediate mechanical behavior with a hardness between 0.1 GPa and 2.9 GPa and enhanced elastic recovery (Wp/We ≈ 3.5–4.7), particularly for anodized substrates. The nanoscratch test results showed that the HAp–Cu coatings exhibited the highest adhesion Lc (≈150–173 mN), confirming a synergistic effect of hybrid composition and heat treatment on interfacial toughness. The present data demonstrate that the optimization of anodizing and EPD processing parameters allows for the manipulation of the mechanical integrity and adhesion of bioactive chitosan-based coatings for titanium biomedical applications. Full article

(This article belongs to the Special Issue Mechanical Behavior and Multiscale Modeling of Advanced Structural Materials)

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22 pages, 1115 KB

Open AccessReview

An Assessment of Fabrication, Properties, and Medical Applications of Chitosan–Nanometal Coatings

by Michał Bartmański

Materials 2025, 18(23), 5322; https://doi.org/10.3390/ma18235322 - 26 Nov 2025

Abstract

Chitosan (chit) is a specific polymer, an oligosaccharide, that demonstrates several important properties alone or in combination with other compounds or elements. These important properties include being biocompatible with the human body and simultaneously effective in destroying bacteria. Moreover, it is a smart [...] Read more.

Chitosan (chit) is a specific polymer, an oligosaccharide, that demonstrates several important properties alone or in combination with other compounds or elements. These important properties include being biocompatible with the human body and simultaneously effective in destroying bacteria. Moreover, it is a smart polymer, as it can change its properties when the pH value decreases below about 7. Therefore, chitosan is widely applied in dermo-cosmetics, but it is also intensively investigated for its use in food preservation and the targeted regeneration of teeth in dentistry. Due to these advantageous characteristics, chitosan has been employed in numerous coating systems for biomedical applications. These coatings can be fabricated through a wide variety of procedures involving different deposition techniques, process parameters, and the chemical characteristics of the environment, solution, air or vacuum, as well as the substrate. Chitosan–metallic coatings have often been investigated; however, the use of elementary metals in the form of nanoparticles (NPs) was rarely reported. The main part of this paper is focused on the presentation of chitosan–metallic NPs, in particular, an application of potentially antibacterial noble and semi-noble metals such as Au, Ag, Cu, and Zn, intensively investigated by the author. The deposition methods and their limitations, the differences in properties of such coatings and those possessing Ag, Sr, Zn, and other metals in the form of cations in chemical compounds, and the perspectives of chit–MeNPs (metal nanoparticles) are thoroughly considered, and future research is proposed. Full article

(This article belongs to the Special Issue Advances in Biomass-Derived and Biodegradable Polymer Materials: Synthesis and Application)

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23 pages, 5573 KB

Open AccessArticle

Biochar Production from Sugarcane Residual Biomass Lignin Through Pyrolysis

by Thiago Claudino Mendes de Almeida, Hélio Merá de Assis, Sarah Inglid dos Santos Silva, Angela Maria Tribuzy de Magalhães Cordeiro, Ramon Kenned Sousa Almeida and Nataly Albuquerque Dos Santos

Materials 2025, 18(23), 5321; https://doi.org/10.3390/ma18235321 - 26 Nov 2025

Abstract

Lignin is the most structurally complex component of lignocellulosic biomass. Each year, thousands of tons of lignin-rich residues from enzymatic hydrolysis are generated in sugarcane-based cellulosic ethanol biorefineries. The current study specifically utilizes lignin extracted from sugarcane bagasse as the primary feedstock for [...] Read more.

Lignin is the most structurally complex component of lignocellulosic biomass. Each year, thousands of tons of lignin-rich residues from enzymatic hydrolysis are generated in sugarcane-based cellulosic ethanol biorefineries. The current study specifically utilizes lignin extracted from sugarcane bagasse as the primary feedstock for biochar production, rather than employing the raw bagasse itself. This study investigates, through pyrolytic thermal treatment of two lignin sources, the production of biochars and the evaluation of their potential applications. Kraft commercial lignin and sugarcane bagasse lignin samples, along with their corresponding biochars, were characterized by elemental and proximate analyses, higher heating value determination, spectroscopic techniques, thermogravimetric analysis, X-Ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, and true density measurements. The results revealed a lower contamination level associated with the extraction process and confirmed the amorphous nature of sugarcane bagasse lignin and its derived biochar. An O/C ratio of approximately 0.3 was obtained for the sugarcane bagasse lignin biochar based on both elemental and Raman spectroscopy analyses. Both elemental composition assessment and Raman spectroscopic analysis indicated that all biochar specimens exhibited hydrogen-to-carbon (H/C) ratios exceeding 0.5. The analyses, therefore, indicated that the biochar derived from sugarcane lignin exhibited higher energy density, moderate stability and a high carbon content. The proposed approach thus provides promising alternatives for the valorizing lignin residues derived from second-generation ethanol production processes. Full article

(This article belongs to the Section Green Materials)

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15 pages, 2011 KB

Open AccessArticle

Quantitative Assessment of Concrete Surface Topography: Effects of Mechanical Treatment and Measurement Resolution

by Slawomir Czarnecki

Materials 2025, 18(23), 5320; https://doi.org/10.3390/ma18235320 - 25 Nov 2025

Abstract

Surface morphology strongly influences the performance and durability of concrete structures, yet the combined effects of mechanical preparation and measurement scale remain insufficiently quantified. This study analyzes three surface conditions, patched, ground, and shot-blasted, using 3D laser scanning measurements acquired at five spatial [...] Read more.

Surface morphology strongly influences the performance and durability of concrete structures, yet the combined effects of mechanical preparation and measurement scale remain insufficiently quantified. This study analyzes three surface conditions, patched, ground, and shot-blasted, using 3D laser scanning measurements acquired at five spatial resolutions. Mechanical surface preparation was found to be the dominant factor shaping morphology: grinding reduced amplitude- and volume-related parameters by approximately 40–70%, while shot blasting increased them by 50–90%, producing highly textured surfaces with an expanded developed area. Measurement resolution additionally affected parameter magnitudes, with coarser sampling intervals reducing scale-sensitive descriptors such as Sdr and Sdq by more than 80–90%. In contrast, parameters including Ssk, Sku, Smr1, and Smr2 varied by less than 5% across scales, demonstrating strong robustness. Patched surfaces exhibited the largest variability (coefficients of variation often exceeding 20–30%) due to manual finishing, whereas mechanically treated surfaces showed more uniform profiles. These quantitative results highlight the coupled influence of preparation method and measurement scale and provide practical guidance for reproducible surface characterization in engineering and material research. Full article

(This article belongs to the Special Issue Structural, Physical and Mechanical Properties of Reinforced Concrete, Novel Cementitious Composites and Other Brittle Construction Materials)

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23 pages, 8038 KB

Open AccessArticle

Preliminary Assessment of Commercial Antibacterial Finishes on Knitted Fabrics from Recycled Cotton and Polyester

by Muhammad Sajid Faheem, Hafsa Jamshaid, Rajesh Kumar Mishra, Adeel Abbas, Miroslav Muller, Jiri Urban and Michal Penc

Materials 2025, 18(23), 5319; https://doi.org/10.3390/ma18235319 - 25 Nov 2025

Abstract

Recycled materials are employed in several areas to reduce the environmental burden. Therefore, recycling textiles is a vast domain being investigated by several researchers. Functionalization of textiles using active nanomaterials is a growing area of interest nowadays. However, functionalized textiles with antibacterial properties [...] Read more.

Recycled materials are employed in several areas to reduce the environmental burden. Therefore, recycling textiles is a vast domain being investigated by several researchers. Functionalization of textiles using active nanomaterials is a growing area of interest nowadays. However, functionalized textiles with antibacterial properties still do not employ the incorporation of recycled materials. The huge consumer need for different types of functional textiles necessitates a focus on recycled textiles in this area. Hence, this research focuses on the development of metal oxide nanoparticle-functionalized antibacterial textiles using recycled cotton and polyester yarns. Two different finishes have been used with a 50:50 ratio. Using a two-fold approach, antibacterial finishes were applied during both the yarn and fabric stages to analyze the differences in performance. Agar plate qualitative antibacterial analysis revealed efficient antibacterial function both before and after commercial laundering. However, thermo-physiological comfort properties were found to be variable for recycled yarn types and finishing stages. The air permeability of fabric-finished specimens was found to be about 47% lower than yarn-finished specimens owing to reduced porosities. However, the overall moisture management capability (OMMC) index was found to be 21% higher than that of yarn-finished specimens. Among serviceability parameters, bursting strength was found to decrease with increasing concentration, as the finishing treatments made the yarns crispier which eventually compromised yarn strength. Full article

(This article belongs to the Special Issue Advances in Waste Materials’ Valorization)

23 pages, 7268 KB

Open AccessArticle

Improved CNN for Predicting Line Heating Forming Deformation of Complex Hull Curved Plate

by Shun Wang, Haohao Jia, Yuxuan Fu, Ji Wang, Rui Li and Zhishuo Shi

Materials 2025, 18(23), 5318; https://doi.org/10.3390/ma18235318 - 25 Nov 2025

Abstract

Shipbuilding requires numerous complex curved plates, with manual line heating forming as the primary processing method for the outer plates of the hull. To solve the problem of automation in curved plate forming, this research investigates intelligent deformation prediction for hull curved plate [...] Read more.

Shipbuilding requires numerous complex curved plates, with manual line heating forming as the primary processing method for the outer plates of the hull. To solve the problem of automation in curved plate forming, this research investigates intelligent deformation prediction for hull curved plate based on improved convolutional neural network (CNN). A numerical calculation model based on the strain direct boundary was established. The feasibility of the model was verified by comparing finite element numerical calculation results with experimental data. To achieve fast prediction of curved plate forming, a deformation prediction model for curved plate forming based on CNN was established. To further enhance the prediction accuracy of the CNN model, particle swarm optimization (PSO) and whale migration algorithm (WMA) were introduced to improve the weights of CNN, PSO-CNN model, and WMA-CNN model were established. Compared with the CNN model, the MAPE of the PSO-CNN model and the WMA-CNN model decreased by 0.31 and 1.36, respectively, for predicting the shrinkage. The MAPE decreased by 1.31 and 4.05, respectively, for predicting the deflection. This results in the WMA-CNN model effectively improving the prediction accuracy compared with the CNN model and PSO-CNN model. The WMA-CNN model is applied for the validation of the case. The relative error of the cases is all within 5%, indicating that the WMA-CNN model is applicable to the intelligent prediction of curved plate forming. This research provides reference for automation forming of hull curved plate. Full article

(This article belongs to the Section Metals and Alloys)

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