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Materials, Volume 18, Issue 8 (April-2 2025) – 204 articles

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15 pages, 5841 KiB  
Article
Investigation of the Process Optimization for L-PBF Hastelloy X Alloy on Microstructure and Mechanical Properties
by Phuangphaga Daram, Masahiro Kusano and Makoto Watanabe
Materials 2025, 18(8), 1890; https://doi.org/10.3390/ma18081890 - 21 Apr 2025
Abstract
The purpose of this study is to investigate the effects of process parameters on the microstructure and mechanical properties of the Hastelloy X (HX) alloy using a laser powder bed fusion (L-PBF) process. A combined experimental and numerical approach was used to evaluate [...] Read more.
The purpose of this study is to investigate the effects of process parameters on the microstructure and mechanical properties of the Hastelloy X (HX) alloy using a laser powder bed fusion (L-PBF) process. A combined experimental and numerical approach was used to evaluate the influence of the energy density distribution and temperature evolution on the microstructure, defects, and mechanical properties. After the specimens were built on SUS304 substrate by the L-PBF, the microstructure and defects in the specimens were analyzed by SEM and EBSD analysis methods, and then the hardness and the tensile tests were performed. The cooling rate under different laser conditions was obtained by the finite element method (FEM). The results show that a low volume energy density (VED) was applied to the unmelted powder particles, and a high energy density resulted in spherical defects. In addition, the microstructures were found to coarsen with increasing the energy density along with a tendency to strengthen the (001) texture orientation in both x–y and x–z planes. Compared to the parts with the thermal history from numerical results, the low cooling rate with high energy density had larger crystal grains elongated along the building direction, coarser sub-grains, resulting in a reduction in microhardness and yield strength together with an increase in elongation for the L-PBF HX alloy. The presented results provide new insights into the effects of parameters and the cooling rates. It can play an important role in optimizing the L-PBF processing parameters, identifying the cause of defects, and controlling the cooling rates for the crystallographic texture in such a way as to guide the development of better metrics for designing processing parameters with the desired mechanical properties. Full article
(This article belongs to the Special Issue Processing–Microstructure–Properties Loop in Materials and Metallurgical Engineering)
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30 pages, 3765 KiB  
Article
Antibacterial Activity of GO-Based Composites Enhanced by Phosphonate-Functionalized Ionic Liquids and Silver
by Xinyu Liu, Xing Zhao, Hongda Qiu, Weida Liang, Linlin Liu, Yunyu Sun, Lingling Zhao, Xiao Wang and Hongze Liang
Materials 2025, 18(8), 1889; https://doi.org/10.3390/ma18081889 - 21 Apr 2025
Abstract
The development of antibiotic-independent antimicrobial materials is critical for addressing bacterial resistance to conventional antibiotics. Currently, there is a lack of comprehensive understanding of ionic liquid-modified composites in antimicrobial applications. Here, we innovatively prepared GO-based composites modified with phosphonate ionic liquids via a [...] Read more.
The development of antibiotic-independent antimicrobial materials is critical for addressing bacterial resistance to conventional antibiotics. Currently, there is a lack of comprehensive understanding of ionic liquid-modified composites in antimicrobial applications. Here, we innovatively prepared GO-based composites modified with phosphonate ionic liquids via a series of surface functionalizations. The resulting antibacterial composites exhibit significant broad-spectrum activity against both Gram-negative and Gram-positive bacteria, including drug-resistant strains, with stronger efficacy against Gram-negative species. Additionally, the material features excellent long-term reusability and the ability to inhibit/destroy biofilms, which is vital for combating persistent infections. Mechanistic studies reveal its antibacterial effects through multiple pathways: disrupting bacterial membranes, inducing ROS, and inactivating intracellular substances—mechanisms less likely to promote resistance. Overall, these phosphonate ionic liquid-modified polycationic materials demonstrate substantial potential in treating bacterial infections, offering a promising strategy to tackle antibiotic resistance challenges. Full article
(This article belongs to the Special Issue Ionic Liquids: New Trends in Advanced Applications)
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20 pages, 5396 KiB  
Article
Reducing Sintering Temperature While Optimizing Electrical Properties of BCZT-Based Lead-Free Ceramics by Adding MnO2 as Sintering Aid
by Xinlin Yang, Bijun Fang, Shuai Zhang, Xiaolong Lu and Jianning Ding
Materials 2025, 18(8), 1888; https://doi.org/10.3390/ma18081888 - 21 Apr 2025
Abstract
In order to reduce the sintering temperature, MnO2 was used as a sintering aid to prepare [(Ba0.85Ca0.15)0.999(Dy0.5Tb0.5)0.001](Zr0.1Ti0.9)O3-x mol% MnO2 (BCDTZT-x mol% MnO2 [...] Read more.
In order to reduce the sintering temperature, MnO2 was used as a sintering aid to prepare [(Ba0.85Ca0.15)0.999(Dy0.5Tb0.5)0.001](Zr0.1Ti0.9)O3-x mol% MnO2 (BCDTZT-x mol% MnO2, x = 0.05, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 3) lead-free piezoelectric ceramics in which the effects of the MnO2 doping amount and sintering temperature on the phase structure, sintering behavior, and electrical properties of the BCDTZT-x mol% MnO2 ceramics were systematically analyzed. All ceramics have a single perovskite structure and coexist in multiple phases. The optimal sintering temperature was reduced from 1515 °C to 1425 °C, and the density of all ceramics was increased as compared with the undoped ceramic, reaching a maximum of 5.38 g/cm3 at x = 0.8 mol%. An appropriate MnO2 doping amount of 0.4 mol% could effectively suppress oxygen vacancies and improve electrical properties, resulting in the best comprehensive performance of the ceramics, with a dielectric constant maximum of 12,817, a high piezoelectric constant of 330 pC/N, and good strain value (Smax = 0.118%) and low strain hysteresis (Hys = 2.66%). The calculation of activation energy indicated that the high-temperature conductivity was dominated by oxygen vacancies in all ceramics. The results showed that the appropriate introduction of MnO2 as a sintering aid could improve the performance of BCZT-based ceramics while reducing the sintering temperature, presenting high practical application value in the fields of low electric field sensors and actuators. Full article
(This article belongs to the Special Issue Performance Testing and Application of Ferroelectric/Piezoelectric Ceramics)
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16 pages, 3557 KiB  
Article
Low-Cycle Fatigue Life Prediction of Titanium-Based Intermetallic Alloys Using Machine Learning and Finite Element Analysis
by Qiwen Xu, Guoqian Song, Xingwu Li, Yanju Wang, Aixue Sha, Yuanyuan Wei and Wenfeng Hao
Materials 2025, 18(8), 1887; https://doi.org/10.3390/ma18081887 - 21 Apr 2025
Abstract
This study explores the low-cycle fatigue characteristics of three structural components fabricated from Ti2AlNb-based alloys utilizing Seeger’s fatigue life theory and an improved Lemaitre damage evolution model. The validity and accuracy of the simulations based on these theoretical methods are verified [...] Read more.
This study explores the low-cycle fatigue characteristics of three structural components fabricated from Ti2AlNb-based alloys utilizing Seeger’s fatigue life theory and an improved Lemaitre damage evolution model. The validity and accuracy of the simulations based on these theoretical methods are verified by experimental fatigue life tests conducted at high temperatures. Additionally, the potential of employing long short-term memory (LSTM), extreme learning machine (ELM), and partial least squares (PLS) algorithms to predict the high-temperature, low-cycle fatigue life of Ti2AlNb alloy components is examined. Comparative analyses of the training effectiveness and practical applicability of these machine learning approaches are conducted, demonstrating that ELM exhibits superior predictive capability. This investigation thus provides a practical and efficient predictive methodology for assessing the low-cycle fatigue life of structural components composed of Ti2AlNb-based alloys. Full article
(This article belongs to the Special Issue Fabrication, Characterization, and Application of High-Temperature Materials and Coatings)
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22 pages, 22135 KiB  
Article
Analysis of the Damage and Failure Mechanism of Q345 Steel Plate with Initial Defect Under Different Temperature Conditions by Peridynamics
by Wudang Ying, Jinhai Zhao, Heipie Zhou, Yuchen Zhu, Yuquan Yang and Xinzan Hu
Materials 2025, 18(8), 1886; https://doi.org/10.3390/ma18081886 - 21 Apr 2025
Abstract
The high temperature performance of steel structures has long been a focus of research, but research on the damage and crack propagation mechanism of steel with initial defects at high temperature is relatively low. The high temperature performance of most steel structures in [...] Read more.
The high temperature performance of steel structures has long been a focus of research, but research on the damage and crack propagation mechanism of steel with initial defects at high temperature is relatively low. The high temperature performance of most steel structures in engineering has an important impact on the function and safety of the whole structure. At present, Peridynamics (PD) theory uses the integral method that has unique advantages compared with traditional methods to solve structural damage and fracture problems. Therefore, the effect of temperature change on steel properties is introduced into the PD, and the PD constitutive equation at high temperature is proposed. The damage and crack propagation mechanisms of 2D Q345 steel plates with bilateral cracks and different bolt holes at 20 °C, 300 °C, 400 °C and 600 °C were analyzed by applying temperature action and external load to double-cracked steel specimens by the direct thermostructural coupling method. At the same time, the damage values, displacement changes in X direction and Y direction under different temperatures were compared and analyzed, and the effects of temperature, bolt hole and external load on the damage, displacement and crack growth path of different parts of the structure were obtained. Full article
(This article belongs to the Special Issue Modeling and Optimization of Material Properties and Characteristics)
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14 pages, 10631 KiB  
Article
3D Printing Assisted Injection Molding of Chemically Plated W-Cu Composite
by Bo Yuan, Wenwxin Liu, Zhen Wang, Zhongkai Li, Xiaofang Pan, Shurong Xu, Shoujing Mao, Ying Wu, Yangyang Li and Jun Liu
Materials 2025, 18(8), 1885; https://doi.org/10.3390/ma18081885 - 21 Apr 2025
Abstract
W-Cu composites are widely used in the fields of switch contact materials and electronic packages because of their high hardness, high plasticity, and excellent thermal conductivity, while the traditional W-Cu composite preparation process is often accompanied by problems such as a long production [...] Read more.
W-Cu composites are widely used in the fields of switch contact materials and electronic packages because of their high hardness, high plasticity, and excellent thermal conductivity, while the traditional W-Cu composite preparation process is often accompanied by problems such as a long production cycle, difficulties in the processing of shaped parts, and difficulties in guaranteeing the uniformity. Therefore, this work developed a chemical plating technique to prepare W-20 wt.% Cu composite powder with a core–shell structure and used this powder as a raw material for powder metallurgy to solve the problem of inhomogeneity in the production of W-Cu composite by the conventional solution infiltration method. Moreover, the work also developed a high-temperature-resistant photosensitive resin, which was used as a raw material to prepare injection molds using photocuring to replace traditional steel molds. Compared to steel molds, which take about a month to prepare, 3D printed plastic molds take only a few hours, greatly reducing the production cycle. At the same time, 3D printing also provides the feasibility of the production of shaped parts. The injection molded blanks were degreased and sintered under different sintering conditions. The results show that the resultant chemically plated W-Cu composite powder has a uniform Cu coating on the surface, and the Cu forms a dense and uniform three-dimensional network in the scanning electron microscope images of each subsequent sintered specimen, while the photocuring-prepared molds were used to prepare the W-Cu shaped parts, which greatly shortened the production cycle. This preparation method enables rapid preparation of tungsten–copper composite-shaped parts with good homogeneity. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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18 pages, 12274 KiB  
Article
Study on Early-Age Capillary Pressure and Plastic Shrinkage Properties of High-Volume Fly Ash Concrete
by Jintao Liu, Xinyang Yu, Shaojiang Wang, Jie Yang and Qianni Cai
Materials 2025, 18(8), 1884; https://doi.org/10.3390/ma18081884 - 21 Apr 2025
Abstract
There is a lack of research on the early plastic deformation and capillary pressure of high-volume fly ash concrete (HVFAC) under varying ambient temperatures. This study aims to investigate the effects of water–binder ratio, fly ash admixture, and ambient temperature on the air [...] Read more.
There is a lack of research on the early plastic deformation and capillary pressure of high-volume fly ash concrete (HVFAC) under varying ambient temperatures. This study aims to investigate the effects of water–binder ratio, fly ash admixture, and ambient temperature on the air entry time T, capillary pressure, and plastic shrinkage of HVFAC. Nine different fly ash concrete materials were designed and analyzed to determine the early plastic deformation and capillary pressure of HVFAC under different ambient temperatures. The dosage of different superplasticizers was adjusted to ensure a slump of 180 mm for all the HVFAC mixtures. The results showed that at 20 °C, T increases with the increase in the water–binder ratio and fly ash admixture, while the effect of T is negligible at 35 °C. The plastic shrinkage of HVFAC increases significantly with the increase in curing temperature, and there is a linear correlation between the air entry time T and the plastic shrinkage value at this time. At low water–binder ratios, the capillary pressure threshold Pa increases with increasing curing temperature, while at high water–binder ratios, there is no significant trend observed for Pa. The findings of the study can provide a theoretical basis for preventing plastic cracking of concrete and optimizing early curing methods. Full article
(This article belongs to the Section Construction and Building Materials)
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18 pages, 7449 KiB  
Article
Physical and Numerical Investigation of Hot Deformation Behavior in Medium-Mn Steel for Automotive Forgings
by Aleksandra Kozłowska, Sebastian Sławski, Wojciech Borek and Adam Grajcar
Materials 2025, 18(8), 1883; https://doi.org/10.3390/ma18081883 - 21 Apr 2025
Abstract
In this study, the hot deformation behavior of novel 0.17C-3.92Mn-1.02Si-0.53Al-0.22Mo-0.032Ti-0.069V steel during continuous compression was predicted using numerical simulation, providing a reference for optimizing the process. Medium-Mn steels have not been applied for forgings yet. Therefore, their industrial application requires detailed investigations on [...] Read more.
In this study, the hot deformation behavior of novel 0.17C-3.92Mn-1.02Si-0.53Al-0.22Mo-0.032Ti-0.069V steel during continuous compression was predicted using numerical simulation, providing a reference for optimizing the process. Medium-Mn steels have not been applied for forgings yet. Therefore, their industrial application requires detailed investigations on their hot deformability. Results of finite element (FEM) simulations will be used for further optimization of the press forging process. The material model parameters used in the FEM method were identified based on stress–strain curves registered during hot compression tests carried out using a Gleeble thermomechanical simulator. The numerical simulation and physical investigations were performed at temperatures of 900, 1000 and 1100 °C to reflect a range of temperatures occurring during press forging. The influence of strain rates of 0.05, 0.5 and 5 s−1 on the flow behavior of steel was also investigated. Colored maps of the plastic strain distribution in a sample volume were obtained as a result of the numerical research. The maps allowed for the identification of differently strengthened zones as a result of varied plastic strain. Results of FEM analysis were experimentally validated by hardness measurements. A good correlation between the hardness and plastic deformation zones was obtained. An increase in the material hardness was identified in the zones characterized by the highest plastic strain. Full article
(This article belongs to the Section Metals and Alloys)
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12 pages, 5558 KiB  
Article
Evolution of the Phase Composition in a Nickel-Predominant NiTi Shape Memory Alloy During High-Energy Ball Milling
by Tomasz Goryczka, Grzegorz Dercz and Maciej Zubko
Materials 2025, 18(8), 1882; https://doi.org/10.3390/ma18081882 - 21 Apr 2025
Abstract
Three alloys differing in their nominal chemical composition (Ni50Ti50, Ni51Ti49, and Ni52Ti48) were produced in the form of powders using high-energy ball milling. Their microstructure, morphology, structure, and phase composition were [...] Read more.
Three alloys differing in their nominal chemical composition (Ni50Ti50, Ni51Ti49, and Ni52Ti48) were produced in the form of powders using high-energy ball milling. Their microstructure, morphology, structure, and phase composition were studied using the X-ray diffraction technique, scanning, and transmission electron microscopy. For the detailed structural analysis, the Rietveld method was used. The results show that each of the alloys consists of three fractions: fine, medium, and thick. The fractions varied in particle/agglomerate size from 200 nm to 800 μm. Additionally, they varied in phase composition. The fine fraction comprised a mixture of amorphous and nanocrystalline phases. Additionally, the medium and coarse phases showed crystalline solid solutions formed on the bases of nickel or titanium, as well as a crystalline bcc phase—a precursor of the parent phase (B2). The largest contribution in the alloy powders, over 80%, comes from the amorphous–nanocrystalline mixture (ANM). The increase in the nickel content resulted in an increase in ANM quantity of 3 wt.%. Similarly, the weight content of the titanium-based solid solution increased to about 7 wt.%. In contrast, the quantity of the nickel-based solid solution decreased from 3 wt.% to approximately 1 wt.% in the Ni50Ti50 and Ni52Ti48 alloys. Full article
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19 pages, 15154 KiB  
Article
Characteristics of Lightweight Foam Concrete Manufactured Using Water-Soluble Polymers and Lightweight Aggregates
by Choonghyun Kang, Ki-Young Seo, Yong-Myung Park and Taewan Kim
Materials 2025, 18(8), 1881; https://doi.org/10.3390/ma18081881 - 21 Apr 2025
Abstract
This study aimed to analyze the effects of PVA aqueous solution as a new foaming agent, and the production and characteristics of ultralight foam concrete using a mixed lightweight aggregate of perlite (PL) and cenosphere (CP). In addition, the application of a new [...] Read more.
This study aimed to analyze the effects of PVA aqueous solution as a new foaming agent, and the production and characteristics of ultralight foam concrete using a mixed lightweight aggregate of perlite (PL) and cenosphere (CP). In addition, the application of a new high-temperature curing process was proposed to improve the foaming effect of PVA and reduce the weight of concrete. The mixing ratios (s/c) of the PVA solution and OPC were 1.0, 1.5, and 2.0, and the ratio of the PVA solution–OPC–lightweight aggregate (perlite and cenosphere) (s/(c + CP + PL)) was 0.43–1.0. As a result, an ultralight foam concrete with a dry density of less than 1.0 g/cm3, an average pore diameter of 0.1–2.3 mm, and a compressive strength of 1.5–10.5 MPa could be manufactured. From the experimental results, PVA showed sufficient usability as a foaming agent. And the new high-temperature curing process proposed in this study could be suggested as a method applicable to the expansion of pores and lightweight reduction in the manufacture of foamed concrete. The diameter of the foamed pores changed depending on the mixing ratio of CP and PL, and the diameter of the foamed pores increased as the ratio of PL increased. However, an increase in the ratio of CP improved the insulation properties. The increase in the OPC ratio increased the mechanical strength, but increased the dry density and decreased the insulation properties. Therefore, the mixing ratio of CP and PL was an important factor affecting the properties of ultralight foam concrete. From the experimental results, PVA was suggested to have sufficient potential as a new foaming agent, and the new high-temperature curing process proposed in this study is expected to be applicable to the production of foam concrete using PVA. Full article
(This article belongs to the Special Issue Emerging Technologies and Materials for Smart, Durable and Sustainable Construction)
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13 pages, 4052 KiB  
Article
Fabrication of Superhydrophobic Surfaces from Laser-Induced Graphene and Their Photothermally Driven Properties
by Yue Zhao, Yonghui Zhang, Yang Chen, Haodong Fu, Hao Liu, Jinlong Song and Xin Liu
Materials 2025, 18(8), 1880; https://doi.org/10.3390/ma18081880 - 21 Apr 2025
Abstract
Conventional LIG preparation mostly relies on the ablation process of a CO2 laser on a polyimide (PI) substrate but is limited by the sensitivity of the laser parameters, which is prone to PI film deformation, non-uniformity of the process, or LIG surface [...] Read more.
Conventional LIG preparation mostly relies on the ablation process of a CO2 laser on a polyimide (PI) substrate but is limited by the sensitivity of the laser parameters, which is prone to PI film deformation, non-uniformity of the process, or LIG surface breakage problems. In this study, we present a new method to fabricate superhydrophobic laser-induced graphene (SH-LIG) surfaces by immobilizing the polyimide (PI) film on the copper sheet, which enables uniform laser processing (single pass laser etching) over a wider range of microsecond laser parameters (10.5–19.5 W). Subsequently, the SH-LIG was obtained by vacuum-assisted immersion in stearic acid, resulting in a water contact angle greater than 150°, roll angle stabilized at 6°, and hydrophobic stability at a high temperature of 90 °C. Analysis by Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) showed that the LIG fabricated at optimal power (19.5 W) had a more developed C sp2 network (I2D/IG ≈ 0.5) and pore structure, which significantly improved the photothermal conversion efficiency (up to 252 °C in air and 180 °C on water). On this basis, a simple micro-driver based on SH-LIG was designed. Experiments showed that the maximum velocity of the SH-LIG boat can reach an adjustable propulsion velocity of 45.6 mm/s (related to the laser processing power and the intensity of the driving light), which is 132% higher than that of the LIG boat. This work provides insights into the preparation of high-quality LIG and their application in photothermally driven micro actuators, highlighting the synergies between structural optimization, surface engineering, and photothermal performance. Full article
(This article belongs to the Special Issue Recent Advances in Advanced Laser Processing Technologies)
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45 pages, 27252 KiB  
Article
Numerical Simulation of Hydrogen Mixing Process in T-Junction Natural Gas Pipeline
by Yangyang Tian, Tongmu Tian, Gaofei Ren and Jiaxin Zhang
Materials 2025, 18(8), 1879; https://doi.org/10.3390/ma18081879 - 20 Apr 2025
Abstract
As a cost-effective transitional strategy, the integrated utilization and transportation of hydrogen and natural gas have gained significant attention as a viable pathway toward carbon neutrality. However, hydrogen’s low density, viscosity, and calorific value cause upward migration and accumulation in pipelines, raising embrittlement [...] Read more.
As a cost-effective transitional strategy, the integrated utilization and transportation of hydrogen and natural gas have gained significant attention as a viable pathway toward carbon neutrality. However, hydrogen’s low density, viscosity, and calorific value cause upward migration and accumulation in pipelines, raising embrittlement risks. Its high diffusion and leakage rates also pose significant safety challenges. To address hydrogen–natural gas blending challenges, achieving uniform mixing is crucial. This study systematically examines hydrogen–methane mixing in T-junction pipelines via numerical simulations, analyzing hydrogen mixing ratios (HMR: 10–25%) and methane flow rates (4–10 m/s) to assess flow and mixing dynamics. The coefficient of variation (COV) quantifies mixing uniformity with spatial and temporal analyses, optimizing hydrogen injection for rapid, homogeneous mixing. The key findings are as follows: (1) The uniform mixing length (the minimum axial distance required for the first pipeline cross-section to achieve 95% mixing uniformity) decreases inversely with the HMR, from 100 D to 20.875 D (D represents the pipeline diameter) as the HMR rises from 10% to 25%. (2) Analysis of initial uniform mixing time (defined as the duration required for the first pipeline cross-section to achieve 95% mixing uniformity) shows significant reduction with increasing HMR. While methane flow rate has a less pronounced effect, it nevertheless contributes to reducing the outlet uniform mixing time (defined as the time required to attain 95% mixing uniformity at the pipeline outlet). (3) A fundamental trade-off in engineering applications is established: increasing the HMR reduces mixing length but extends overall mixing time (difference between outlet and initial mixing times), while higher methane flow rates shorten overall mixing time at the cost of increased mixing length. The primary objective of this research is to elucidate the fundamental fluid dynamics of hydrogen–methane mixtures in T-junction pipelines, providing scientific insights for the safe and efficient operation of hydrogen-blended natural gas pipeline systems. Full article
(This article belongs to the Special Issue Multiscale Characterization and Computational Modeling/Simulation of Metallic Materials)
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16 pages, 5464 KiB  
Article
Regulation Mechanism of Different Metal Cations on the Structure and Gel Properties of Montmorillonite
by Sixiao Wang, Dinghua Liu, Tiantian Zhang, Haowei Yan, Zepeng Zhang and Junming Geng
Materials 2025, 18(8), 1878; https://doi.org/10.3390/ma18081878 - 20 Apr 2025
Abstract
Metal cations are often used to regulate montmorillonite, but the mechanism is still unclear. In this paper, the regulation of different cations in montmorillonite was studied, and it was found that the regulation of different cations had significant effects on the structure of [...] Read more.
Metal cations are often used to regulate montmorillonite, but the mechanism is still unclear. In this paper, the regulation of different cations in montmorillonite was studied, and it was found that the regulation of different cations had significant effects on the structure of montmorillonite. Firstly, the viscosity is negatively correlated with particle size, and the order of particle size is trivalent > divalent > monovalent cation. Secondly, the swelling capacity is positively correlated with the absolute value of zeta potential, and the order of the zeta potential is monovalent > trivalent > divalent cation. Thirdly, the smaller hydrated ion radius and static electricity of monovalent cations significantly reduce the layer spacing. Meanwhile, isomorphism displacement results in a significant increase in the proportion of cis-vacant configuration due to changing the electronegativity of the octahedron. The comprehensive performance is that the particle size is significantly reduced and the absolute value of zeta potential is significantly increased. It is easy to peel off and expand in water to form a uniform and stable colloidal substance, which has the best gel performance. The research results can provide theoretical support for the regulation of montmorillonite structure and gel properties by different valence metal cations. Full article
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18 pages, 3386 KiB  
Article
Fracture Analysis of Concrete Structures: Prediction Based on Boundary Effect Model
by Gang Han, Xiangyu Han, Yi Ji and Xiaozhi Hu
Materials 2025, 18(8), 1877; https://doi.org/10.3390/ma18081877 - 20 Apr 2025
Abstract
A simple design model, able to link test results of small concrete samples to failures of large structures, is desirable for fracture analysis of concrete structures, particularly if the model has no special requirements on small samples, e.g., size, notched or un-notched. The [...] Read more.
A simple design model, able to link test results of small concrete samples to failures of large structures, is desirable for fracture analysis of concrete structures, particularly if the model has no special requirements on small samples, e.g., size, notched or un-notched. The linear Boundary Effect Model (BEM, which has evolved over the past 20 years, is able to provide the link between small samples and large structures with fairly reliable predictions and a built-in function of statistical analysis. BEM enables researchers and engineers to model the quasi-brittle fracture behavior of concrete and the associated size effects by focusing on the fracture process zone (FPZ) at the notch tip or at the specimen boundary (for an un-notched case). FPZ and quasi-brittle fracture of concrete are directly influenced by the average aggregate size (dav), but few models mathematically show such critical aggregate influence, except BEM. The aggregate size used in BEM can be accurately estimated separately before fracture experiments. A comprehensive dataset of concrete fracture results from the existing literature, along with a new experimental dataset from three-point bending (3-P-B) tests, involving 138 specimens with varying notch depths (un-notched, 1 mm shallow-notched, and 6 mm deep-notched) was analyzed. The specimens, which present inconsistent dimensions (160 mm span, approximately 40 mm thickness, and 38 mm width/height), were used to estimate FPZ at peak fracture loads and investigate their interactions with structural boundaries. Statistical analyses were integrated into BEM, allowing the model to account for the experimental scatter, thus improving its reliability as a predictive tool for maximum fracture loads of concrete structures. This study confirmed again that the linear BEM is easy to use and provides fairly accurate predictions across concrete specimens and structures of various sizes. Full article
(This article belongs to the Section Construction and Building Materials)
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18 pages, 16129 KiB  
Article
TaMoNbTiZr Multielement Alloy for Medical Instruments
by Ileana Mariana Mates, Victor Geanta, Doina Manu, Hajnal Kelemen, Adrian Emanuel Onici, Julia Claudia Mirza-Rosca and Ionelia Voiculescu
Materials 2025, 18(8), 1876; https://doi.org/10.3390/ma18081876 - 20 Apr 2025
Viewed by 63
Abstract
In this paper, a new TaMoNbTiZr multielement alloy has been designed, using chemical elements that exhibit extremely low bio-toxicity for the human body. The alloy was obtained by melting in vacuum arc remelting (VAR) equipment MRF ABJ 900 from high-purity chemical elements (99.5%) [...] Read more.
In this paper, a new TaMoNbTiZr multielement alloy has been designed, using chemical elements that exhibit extremely low bio-toxicity for the human body. The alloy was obtained by melting in vacuum arc remelting (VAR) equipment MRF ABJ 900 from high-purity chemical elements (99.5%) as mini-ingots having about 40 g weight each. The biocompatible alloys underwent changes in hardness after performing the annealing at 900 °C for 2 h, followed by cooling in water. The new alloy had an average hardness in the cast state of 545 HV0.5, and after heat treatment, it hardened to a value of 984 HV0.5, over 40% higher than that in the casting state, which ensures a longer working period. To use them as materials for medical instruments, their biocompatibility was highlighted through specific laboratory tests. For this, mesenchymal stem cells isolated from bone tissue and a human fibroblast cell line were cultured in vitro on the TaMoNbTiZr alloy’s surface. The biocompatibility of the alloy with the biological environment was evaluated by analyzing cell viability, adhesion, and proliferation, and in parallel, the cytolysis effects manifested by the increase in lactate dehydrogenase activity in the culture media were analyzed. Full article
(This article belongs to the Section Metals and Alloys)
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11 pages, 2954 KiB  
Article
Study on the Approach to Obtaining Mechanical Properties Using Digital Image Correlation Technology
by Shuai Wang, Bin Wang, Shengyong Mu, Jianlong Zhang, Yubiao Zhang and Xiaoyan Gong
Materials 2025, 18(8), 1875; https://doi.org/10.3390/ma18081875 - 19 Apr 2025
Viewed by 117
Abstract
Accurate mechanical property parameters constitute an indispensable guarantee for the accuracy of finite element simulations. Traditionally, uniaxial tensile tests are instrumental in acquiring the stress–strain data of materials during elongation, thereby facilitating the determination of the materials’ mechanical property parameters. By capitalizing on [...] Read more.
Accurate mechanical property parameters constitute an indispensable guarantee for the accuracy of finite element simulations. Traditionally, uniaxial tensile tests are instrumental in acquiring the stress–strain data of materials during elongation, thereby facilitating the determination of the materials’ mechanical property parameters. By capitalizing on the digital image correlation (DIC) non-contact optical measurement technique, the entire test can be comprehensively documented using high-speed cameras. Subsequently, through in-depth analysis and meticulous numerical computations enabled by computer vision technology, the complete strain evolution of the specimen throughout the test can be precisely obtained. In this study, a comparison was made between the application of strain gauges and DIC testing systems for measuring the strain alterations during the tensile testing of 316L stainless steel, which serves as the material for the primary circuit pipelines of pressurized water reactor (PWR) nuclear power plants (NPPs). The data procured from these two methods were utilized as material mechanical parameters for finite element simulations, and a numerical simulation of the uniaxial tensile test was executed. The results reveal that, within the measuring range of the strain gauge, the DIC method generates measurement outcomes that are virtually identical to those obtained by strain gauges. Given its wider measurement range, the DIC method can be effectively adopted in the process of obtaining material mechanical parameters for finite element simulations. Full article
(This article belongs to the Special Issue Advances in Modelling and Simulation of Materials in Applied Sciences)
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14 pages, 4721 KiB  
Article
Molecular Ir-Based Coordination Compound Grafted onto Covalent Organic Framework for Efficient Photocatalytic H2 Evolution
by Chao Wu, Haoyan Zhang, Xuan Zheng, Jing Ding, Yuanyuan Li, Feiyong Chen and Zhengfeng Zhao
Materials 2025, 18(8), 1874; https://doi.org/10.3390/ma18081874 - 19 Apr 2025
Viewed by 90
Abstract
The urgency of reducing pollution and developing clean energy storage requires efficient photocatalytic hydrogen evolution (PHE) tactics. To improve solar conversion efficiency, it is highly imperative to accelerate the photocarriers separation and transport through materials design. A stable hydrogen evolution photocatalyst based on [...] Read more.
The urgency of reducing pollution and developing clean energy storage requires efficient photocatalytic hydrogen evolution (PHE) tactics. To improve solar conversion efficiency, it is highly imperative to accelerate the photocarriers separation and transport through materials design. A stable hydrogen evolution photocatalyst based on TpPa-COFs (triformylphloroglucinol phenylenediamine covalent organic frameworks) was developed by a molecular-level design strategy. The study successfully introduced a molecular-scale Ir active site onto the surface of TpPa-COFs via coordination bonds. It verified the structural integrity of TpPa-COFs and the existence of Ir through the basic structural characterizations, such as Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). After the Ir-based coordination compound joining, the absorption edge of TpPa-COF-M1 and TpPa-COF-M2 was extended to 750 nm. The TpPa-COF + M1 exhibited the highest photocatalytic H2 evolution rate of 662 µmol/h (10 mg catalyst) under visible-light (λ ≥ 420 nm) irradiation. The apparent quantum yield (AQY) of TpPa-COF-M1 is calculated to be 1.9%, 3.8%, 4.8%, 2.8%, 1.8%, and 0.3% at monochromatic wavelengths of 420, 450, 470, 500, 550, and 600 nm, respectively. Our findings confirm that the molecular-level design of photocatalysts can effectively boost performance and reduce cost in photocatalytic reactions and provide an important strategy for designing efficient photocatalysts. Full article
(This article belongs to the Section Catalytic Materials)
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26 pages, 13683 KiB  
Article
Application of Voronoi Tessellation to the Additive Manufacturing of Thermal Barriers of Irregular Porous Materials—Experimental Determination of Thermal Properties
by Beata Anwajler
Materials 2025, 18(8), 1873; https://doi.org/10.3390/ma18081873 - 19 Apr 2025
Viewed by 135
Abstract
The issue of energy transfer is extremely important. In order to achieve the lowest possible energy consumption and the required thermal efficiency in energy-efficient buildings, it is necessary, among other things, to minimize the heat-transfer coefficient, which depends on the properties of the [...] Read more.
The issue of energy transfer is extremely important. In order to achieve the lowest possible energy consumption and the required thermal efficiency in energy-efficient buildings, it is necessary, among other things, to minimize the heat-transfer coefficient, which depends on the properties of the insulating material. Analyses of the relationship between the structure of a material and its thermal conductivity coefficient have shown that lower values of this coefficient can be achieved with a more complex structure that mimics natural forms. This paper presents a design method based on the Voronoi diagram to obtain a three-dimensional structure of a porous composite material. The method was found to be effective in producing structures with predefined and functionally graded porosity. The porous specimens were fabricated from a biodegradable soybean oil-based resin using mSLA additive technology. Analyses were performed to determine the thermal parameters of the anisotropic composites. Experimental results showed that both porosity and irregularity affect the thermal properties. The lowest thermal conductivity coefficients were obtained for a 100 mm-thick prototype composite with the following parameters: wall thickness D = 0.2 mm, cell size S = 4 mm, number of structural layers n = 2, and degree of irregularity R = 4. The lowest possible thermal conductivity of the insulation was 0.026 W/(m·K), and the highest possible thermal resistance was 3.92 (m2·K)/W. The method presented in this study provides an effective solution for nature-inspired design and topological optimization of porous structures. Full article
(This article belongs to the Special Issue Materials for Additive Manufacturing Processes)
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14 pages, 12032 KiB  
Article
Fabrication of Stainless Steel/Alumina Composite Powders by Spray Granulation and Plasma Spheroidization
by Elodie Cabrol, Sandrine Cottrino, Hocine Si-Mohand and Gilbert Fantozzi
Materials 2025, 18(8), 1872; https://doi.org/10.3390/ma18081872 - 19 Apr 2025
Viewed by 98
Abstract
This work presents a new approach for the fabrication of 316L/Al2O3 composites, based on a combination of spray granulation, radio frequency (RF) plasma spheroidization and spark plasma sintering (SPS). Initially, a suspension containing 316L and alumina powders is formulated by [...] Read more.
This work presents a new approach for the fabrication of 316L/Al2O3 composites, based on a combination of spray granulation, radio frequency (RF) plasma spheroidization and spark plasma sintering (SPS). Initially, a suspension containing 316L and alumina powders is formulated by precisely adjusting the pH and selecting an appropriate dispersant, thereby ensuring homogeneous dispersion of the constituents. The spray granulation process then produces granules with controlled size and morphology. RF plasma spheroidization, carried out using a TekSphero-40 system, is investigated by varying parameters such as the power, gas flow rates, injection position and feed rate, in order to optimize the formation of spherical and dense particles. The analysis reveals a marked sensitivity to heat transfer from the plasma to the particles, with a tendency for fine particles to segregate, which underscores the necessity for precise control of the processing conditions. Finally, SPS densification, performed under a constant pressure and a rigorously controlled thermal cycle, yields composites with excellent density and hardness characteristics. This study thus demonstrates that the proposed hybrid process offers an optimal synergy between a uniform distribution of alumina and a controlled microstructure, opening up promising avenues for the design of high-performance composite materials for demanding applications. Full article
(This article belongs to the Section Metals and Alloys)
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24 pages, 2545 KiB  
Article
Effectiveness of Different Categories of Light Oils in Partially Reactive Crumb Rubber-Modified Asphalt
by Dean Wen, Dongdong Ge, Yantao Wang, Songtao Lv, Qian Liu and Shuxian Liu
Materials 2025, 18(8), 1871; https://doi.org/10.3390/ma18081871 - 19 Apr 2025
Viewed by 47
Abstract
Rubber-modified asphalt (RMA) faces several challenges, including poor workability, difficult construction, and high energy consumption. The incorporation of renewable light oils offers a promising solution to address issues such as high viscosity and elevated carbon emissions in asphalt modified with a high dosage [...] Read more.
Rubber-modified asphalt (RMA) faces several challenges, including poor workability, difficult construction, and high energy consumption. The incorporation of renewable light oils offers a promising solution to address issues such as high viscosity and elevated carbon emissions in asphalt modified with a high dosage of rubber powder. The investigation of light oil and rubber powder composite-modified asphalt under low-temperature (160 °C) and short-term (30 min) shear processes is essential for understanding its rheological behavior and modification mechanism. This study explores composite-modified asphalt prepared with four types of light oils (fatty acids, aromatic oil, tall oil, and paraffin oil) at dosages of 10% and 15%, combined with 20% rubber powder. Conventional penetration and viscosity tests were carried out to assess the overall physical properties of the composite-modified asphalts, while rheological tests were conducted to examine their performance at high temperatures. Fourier transform infrared spectroscopy (FTIR) and fluorescence microscopy (FM) were employed to explore the interaction mechanisms that occurred between the light oils, rubber powder, and asphalt. The results suggest that the addition of various light oils leads to a reduction in the viscosity of rubber-modified asphalt, with the extent of reduction varying across different oils. Notably, 10% tall oil demonstrates the most significant reduction in viscosity while also facilitating the dissolution of rubber powder. The high-temperature PG-grade rubberized asphalt improved with the incorporation of light oils, with 5% tall oil yielding the highest PG grade of PG 82-34. FTIR analysis confirmed that light oils and rubber were physically blended in the asphalt, with the light components of the oils being absorbed by the asphalt. FM observations revealed that light oils promote the swelling of rubber particles, with the rubber particles fully swelling in tall oil. Considering the reduction in viscosity, the performance at both high and low temperatures, elasticity, and the extent of rubber particle swelling, tall oil is identified as the most effective material for preparing light oil–rubber composite-modified asphalt using the low-temperature, short-term shear process. Full article
(This article belongs to the Special Issue Advanced Rubber Composites (3rd Edition）)
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20 pages, 14968 KiB  
Article
Plasma Photocatalysis: A Novel Approach for Enhanced Air Disinfection in Centralised Ventilation Systems
by Hanna Koshlak, Leonid Lobanov, Borys Basok, Tetyana Hrabova and Pavlo Goncharov
Materials 2025, 18(8), 1870; https://doi.org/10.3390/ma18081870 - 19 Apr 2025
Viewed by 109
Abstract
The COVID-19 pandemic highlighted the urgent need for sustainable and scalable air disinfection technologies in HVAC systems, addressing the limitations of energy-intensive and chemically intensive conventional methods. This study developed and evaluated a pilot experimental installation integrating plasma chemistry and photocatalysis for airborne [...] Read more.
The COVID-19 pandemic highlighted the urgent need for sustainable and scalable air disinfection technologies in HVAC systems, addressing the limitations of energy-intensive and chemically intensive conventional methods. This study developed and evaluated a pilot experimental installation integrating plasma chemistry and photocatalysis for airborne pathogen and pollutant mitigation. The installation, designed with a modular architecture to simulate real-world HVAC dynamics, employed a bipolar plasma ioniser, a TiO2 photocatalytic module, and an adsorption-catalytic module for ozone abatement. Characterization techniques, including SEM and BET analysis, were used to evaluate the morphology and surface properties of the catalytic materials. Field tests in a production room demonstrated a 60% reduction in airborne microflora in three days, along with effective decomposition of ozone. The research also determined the optimal electrode geometry and interelectrode distance for stable corona discharge, which is essential for efficient plasma generation. Energy-efficient design considerations, which incorporate heat recovery and heat pump integration, achieved a 7–8-fold reduction in air heating energy consumption. These results demonstrate the potential of integrated plasma photocatalysis as a sustainable and scalable approach to enhance indoor air quality in centralised HVAC systems, contributing to both public health and energy efficiency. Full article
(This article belongs to the Special Issue Catalysis: Where We Are and Where We Go)
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16 pages, 13256 KiB  
Article
Novel Stable Co3O4-SnO2 Heterojunction Electrocatalysts with Low Oxygen Evolution Potential
by Bingfeng Yan, Wen Liu, Youchen Sun, Meng Gao, Aqing Chen and Jun Zhang
Materials 2025, 18(8), 1869; https://doi.org/10.3390/ma18081869 - 19 Apr 2025
Viewed by 99
Abstract
Proton exchange membrane (PEM) water electrolysis offers a sustainable route for hydrogen production, yet the reliance on costly noble metal-based anodes hinders scalability. Tin dioxide (SnO2) emerges as a promising alternative due to its acid stability, but its high oxygen evolution [...] Read more.
Proton exchange membrane (PEM) water electrolysis offers a sustainable route for hydrogen production, yet the reliance on costly noble metal-based anodes hinders scalability. Tin dioxide (SnO2) emerges as a promising alternative due to its acid stability, but its high oxygen evolution potential (OEP) limits practical application in hydrogen production via water electrolysis. Here, we address this challenge by incorporating cobalt (Co) into SnO2 to create a heterojunction electrocatalyst. The optimized Co3O4-SnO2 heterojunction catalyst with a tin-to-cobalt mass ratio of 3:1 exhibits a significantly reduced OEP (1.6 V vs. RHE) and an overpotential of 186 mV at 10 mA cm−2 in acidic media, outperforming undoped SnO2. Stability tests reveal a lifespan exceeding 24 h at 100 mA cm−2, a threefold improvement over pure SnO2. This work underscores the potential of the Co3O4-SnO2 heterojunction electrocatalyst as a cost-effective, durable anode catalyst for PEM electrolyzers. Full article
(This article belongs to the Section Catalytic Materials)
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17 pages, 4793 KiB  
Article
Ultrafast Rechargeable Aluminum-Chlorine Batteries Enabled by a Confined Chlorine Conversion Chemistry in Molten Salts
by Junling Huang, Linhan Xu, Yu Wang, Xiaolin Wu, Meng Zhang, Hao Zhang, Xin Tong, Changyuan Guo, Kang Han, Jianwei Li, Jiashen Meng and Xuanpeng Wang
Materials 2025, 18(8), 1868; https://doi.org/10.3390/ma18081868 - 18 Apr 2025
Viewed by 112
Abstract
Rechargeable metal chloride batteries, with their high discharge voltage and specific capacity, are promising for next-generation sustainable energy storage. However, sluggish solid-to-gas conversion kinetics between solid metal chlorides and gaseous Cl2 cause unsatisfactory rate capability and limited cycle life, hindering their further [...] Read more.
Rechargeable metal chloride batteries, with their high discharge voltage and specific capacity, are promising for next-generation sustainable energy storage. However, sluggish solid-to-gas conversion kinetics between solid metal chlorides and gaseous Cl2 cause unsatisfactory rate capability and limited cycle life, hindering their further applications. Here we present a rechargeable aluminum-chlorine (Al-Cl2) battery that relies on a confined chlorine conversion chemistry in a molten salt electrolyte, exhibiting ultrahigh rate capability and excellent cycling stability. Both experimental analysis and theoretical calculations reveal a reversible solution-to-gas conversion reaction between AlCl4− and Cl2 in the cathode. The designed nitrogen-doped porous carbon cathode enhances Cl2 adsorption, thereby improving the cycling lifespan and coulombic efficiency of the battery. The resulting Al-Cl2 battery demonstrates a high discharge plateau of 1.95 V, remarkable rate capability without capacity decay at different rates from 5 to 50 A g−1, and good cycling stability with over 1200 cycles at a rate of 10 A g−1. Additionally, we implemented a carbon nanofiber membrane on the anode side to mitigate dendrite growth, which further extends the cycle life to 3000 cycles at an ultrahigh rate of 30 A g−1. This work provides a new perspective on the advancement of high-rate metal chloride batteries. Full article
(This article belongs to the Special Issue Advanced Electrode Materials for Batteries: Design and Performance)
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18 pages, 11198 KiB  
Article
Insight into the Common W-Shaped Uneven Solidification Profile in Slab Casting: From Mechanisms to Targeted Strategies
by Hao Geng, Feifei Yang, Shuaikang Xia, Pu Wang, Jinwen Jin and Jiaquan Zhang
Materials 2025, 18(8), 1867; https://doi.org/10.3390/ma18081867 - 18 Apr 2025
Viewed by 145
Abstract
This study elucidates the underlying formation mechanisms and mitigation strategies for the W-shaped solidification profile in slab continuous casting. Through the development of a multiphysics coupling numerical model, integrated with measured nozzle cooling characteristics in the secondary cooling zone, the effect of steel [...] Read more.
This study elucidates the underlying formation mechanisms and mitigation strategies for the W-shaped solidification profile in slab continuous casting. Through the development of a multiphysics coupling numerical model, integrated with measured nozzle cooling characteristics in the secondary cooling zone, the effect of steel flow patterns in mold and non-uniform cooling conditions in the secondary cooling zone on solidifying shell evolution is systematically studied. A principal finding is that wide-face shell erosion, induced by both the radial expansion jet and the lower recirculation, constitutes the primary determinant of uneven shell thickness. An increase in the immersion depth and inclination angle of the nozzle side-hole exacerbates the non-uniformity of the solidified shell. Non-uniform cooling in the secondary cooling zone further amplifies the shell thickness differences, culminating in characteristic dumbbell-shaped solidified shell geometry. Strategic implementation of localized enhanced cooling on the wide face in the secondary cooling zone demonstrates significant improvement in shell uniformity, with implementation efficacy contingent upon a critical process window (Segments 1–6). These findings establish mechanistic foundations and deliver practical guidance for minimizing centerline segregation through optimized continuous casting parameter configuration. Full article
(This article belongs to the Special Issue Research on Metal Cutting, Casting, Forming, and Heat Treatment)
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18 pages, 5299 KiB  
Article
Effects of Harmless Municipal Solid Waste Incineration Fly Ash on the Macroscopic Properties and Microstructure of Recycled Aggregate Concrete
by Bochen Song, Yefan Li and Wengang Zhang
Materials 2025, 18(8), 1866; https://doi.org/10.3390/ma18081866 - 18 Apr 2025
Viewed by 170
Abstract
With the increasing rate of urbanization and the annual rise in municipal domestic waste, the use of harmless municipal solid waste incineration fly ash (HMSWIFA) as a construction material has been gradually adopted and promoted. However, significant differences exist in how various characteristics [...] Read more.
With the increasing rate of urbanization and the annual rise in municipal domestic waste, the use of harmless municipal solid waste incineration fly ash (HMSWIFA) as a construction material has been gradually adopted and promoted. However, significant differences exist in how various characteristics of HMSWIFA affect the performance of recycled aggregate concrete (RCA). To analyze the effects of HMSWIFA content and particle size on the macroscopic properties and microstructure of RCA, this paper conducts compressive, flexural, frost resistance, and Scanning Electron Microscope (SEM) characterization on RCA with varying dosages and particle sizes of HMSWIFA as a cement replacement. The results indicate that HMSWIFA enhances the compressive strength (CS) and frost resistance of RCA. Experimental data reveal that HMSWIFA with a particle size of 600–900 μm exhibits the best modification effect at an admixture level of 10–15%: the 28-day CS increased by 1.90–3.60%, the mass loss after freezing and thawing decreased by 0.37–0.45%, and the increase in dynamic elastic modulus reached 16.09–16.44%. Notably, the flexural strength (FS) experienced a reduction of 1.81% at a high dosage of the optimal particle size. This study elucidates the coupling relationship of “particle size-admixture-performance” in HMSWIFA-modified recycled concrete, demonstrating that reasonable control of the particle size distribution of HMSWIFA can achieve a synergistic effect of mechanical enhancement and durability improvement. The research findings provide a valuable reference for the application of municipal waste incineration HMSWIFA in RCA, facilitating the recycling of waste resources to mitigate pollution and enhance energy efficiency. Full article
(This article belongs to the Special Issue Advanced Green Building Materials: Synthesis, Characterization and Sustainable Development Technologies)
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18 pages, 5388 KiB  
Article
Valorization of Soybean Peel-Derived Humins for Carbon Dot (CD) Production
by Onofrio Losito, Thomas Netti, Veronika Kost, Cosimo Annese, Lucia Catucci, Tatiana Da Ros, Vincenzo De Leo and Lucia D’Accolti
Materials 2025, 18(8), 1865; https://doi.org/10.3390/ma18081865 - 18 Apr 2025
Viewed by 110
Abstract
Over the past few decades, awareness has risen substantially about the limitations of non-renewable resources and the environmental challenges facing the chemical industry. This has necessitated a transition toward renewable resources, such as lignocellulosic biomass, which is among the most abundant renewable carbon [...] Read more.
Over the past few decades, awareness has risen substantially about the limitations of non-renewable resources and the environmental challenges facing the chemical industry. This has necessitated a transition toward renewable resources, such as lignocellulosic biomass, which is among the most abundant renewable carbon sources on the planet. Lignocellulosic biomass represents a significant yet often underutilized source of fermentable sugars and lignin, with potential applications across multiple sectors of the chemical industry. The formation of humins (polymeric byproducts with a complex conjugated network, comprising furanic rings and various functional groups, including ketones) occurs inevitably during the hydrothermal processing of lignocellulosic biomass. This study presents the use of humin byproducts derived from soybean peels for the production of fluorescent carbon dots (CDs). A comparison between sonochemical and thermochemical methods was conducted for the synthesis of this nanomaterial. The obtained nanoparticles were characterized in terms of size, morphology (TEM, DLS), and Z-potential. Subsequently, the spectroscopic properties of the prepared CDs were studied using absorption and emission spectroscopy. In particular, the CDs displayed a blue/cyan fluorescence under UV irradiation. The emission properties were found to be dependent on the excitation wavelength, shifting to longer wavelengths as the excitation wavelength increased. The carbon dots that exhibited the most favorable photochemical properties (QY = 2.5%) were those produced through a sonochemical method applied to humins obtained from the dehydration of soybean husks with phosphoric acid and prior treatment. Full article
(This article belongs to the Collection Advanced Biomass-Derived Carbon Materials)
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19 pages, 5103 KiB  
Article
Preparation and Post-Processing of Three-Dimensional Printed Porous Titanium Alloys
by Tairong Li, Mengyu Xu, Jinzhi Yao, Liping Deng and Bingshu Wang
Materials 2025, 18(8), 1864; https://doi.org/10.3390/ma18081864 - 18 Apr 2025
Viewed by 102
Abstract
Ti6Al4V is widely utilized in orthopedic implants due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, traditional solid titanium implants exhibit an elastic modulus (90–115 GPa) significantly higher than that of human bone (10–30 GPa), leading to stress shielding and implant [...] Read more.
Ti6Al4V is widely utilized in orthopedic implants due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, traditional solid titanium implants exhibit an elastic modulus (90–115 GPa) significantly higher than that of human bone (10–30 GPa), leading to stress shielding and implant loosening. To address this, porous titanium alloys have been developed to better match bone elasticity. Additive manufacturing, particularly selective laser melting (SLM), enables precise control over pore size and porosity, thereby tuning mechanical properties. Nevertheless, SLM-produced porous structures often suffer from powder adhesion, which compromises bone integration and patient safety. In this study, bulk Ti6Al4V samples were fabricated via SLM with a fixed laser power of 200 W and varying scanning speeds (800–1400 mm/s). Density measurements and surface defect analysis identified 1200 mm/s as the optimal scanning speed. Cubic unit cell scaffolds with different pore diameters (400, 600, 800 μm) and porosities (60%, 80%) were subsequently designed. Compression tests revealed that scaffolds with a 400 μm pore diameter and 60% porosity exhibited the highest compressive strength (794 MPa) and fracture strain (41.35%). Chemical polishing using a diluted HF-HNO3 solution (1:2:97) effectively removed adhered powder without significant structural degradation, with 40 min identified as the optimal polishing duration. Full article
(This article belongs to the Special Issue Design and Application of Additive Manufacturing: 3rd Edition)
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22 pages, 2825 KiB  
Systematic Review
Recent Use of Hyaluronic Acid in Dental Medicine
by Giuseppina Malcangi, Alessio Danilo Inchingolo, Irma Trilli, Laura Ferrante, Lucia Casamassima, Paola Nardelli, Francesco Inchingolo, Andrea Palermo, Marco Severino, Angelo Michele Inchingolo and Gianna Dipalma
Materials 2025, 18(8), 1863; https://doi.org/10.3390/ma18081863 - 18 Apr 2025
Viewed by 106
Abstract
This systematic review evaluates the clinical effectiveness of hyaluronic acid (HA) in periodontal therapy, oral surgery, and temporomandibular joint (TMJ) disorders. Background. HA, a biocompatible glycosaminoglycan with anti-inflammatory and regenerative properties, is increasingly used in dentistry to enhance healing, reduce pain, and support [...] Read more.
This systematic review evaluates the clinical effectiveness of hyaluronic acid (HA) in periodontal therapy, oral surgery, and temporomandibular joint (TMJ) disorders. Background. HA, a biocompatible glycosaminoglycan with anti-inflammatory and regenerative properties, is increasingly used in dentistry to enhance healing, reduce pain, and support periodontal regeneration. However, its efficacy compared to conventional treatments remains debated. Materials and Methods. A systematic search was conducted following PRISMA guidelines across PubMed, Scopus, and Web of Science databases (2015–2025). Twenty-one clinical studies, including randomized controlled trials (RCTs) and case-control studies, were analyzed for outcomes related to pain reduction, tissue regeneration, and functional recovery. HA improved clinical attachment levels, reduced probing depth, and enhanced wound healing in periodontal therapy and oral surgery. It accelerated healing after extractions and frenectomies. However, TMJ disorder studies showed mixed results, with some reporting pain relief and functional improvement, while others found no significant advantage over platelet-rich plasma (PRP) or corticosteroids. Variability in HA formulations and protocols influenced outcomes. HA is a promising adjunct for periodontal therapy and wound healing. However, its role in TMJ treatment remains uncertain. Further RCTs with standardized protocols are needed to determine its optimal clinical application. Full article
(This article belongs to the Special Issue Advanced Materials for Oral Application (3rd Edition))
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50 pages, 3490 KiB  
Systematic Review
Recent Advances in Carbon-Based Sensors for Food and Medical Packaging Under Transit: A Focus on Humidity, Temperature, Mechanical, and Multifunctional Sensing Technologies—A Systematic Review
by Siting Guo, Iza Radecka, Ahmed M. Eissa, Evgeni Ivanov, Zlatka Stoeva and Fideline Tchuenbou-Magaia
Materials 2025, 18(8), 1862; https://doi.org/10.3390/ma18081862 - 18 Apr 2025
Viewed by 235
Abstract
All carbon-based sensors play a critical role in ensuring the sustainability of smart packaging while enabling real-time monitoring of parameters such as humidity, temperature, pressure, and strain during transit. This systematic review covers the literature between 2013 and 16 November 2024 in the [...] Read more.
All carbon-based sensors play a critical role in ensuring the sustainability of smart packaging while enabling real-time monitoring of parameters such as humidity, temperature, pressure, and strain during transit. This systematic review covers the literature between 2013 and 16 November 2024 in the Scopus, Web of Science, IEEE Xplore, and Wiley databases, focusing on carbon-based sensor materials, structural design, and fabrication technologies that contribute to maximizing the sensor performance and scalability with particular emphasis on food and pharmaceutical product packaging applications. After being subjected to the inclusion and exclusion criteria, 164 studies were included in this review. The results show that most humidity sensors are made using graphene oxide (GO), though there is some progress toward cellulose and cellulose-based materials. Graphene and carbon nanotubes (CNTs) are predominant in temperature and mechanical sensors. The application of composites with structural design (e.g., porous and 3D structures) significantly improves sensitivity, long-term stability, and multifunctionality, whereas manufacturing methods such as spray coating and 3D printing further drive production scalability. The transition from metal to carbon-based electrodes could also reduce the cost. However, the scalability, long-term stability, and real-world validation remain challenges to be addressed. Future research should further enhance the performance and scalability of carbon-based sensors through low-energy fabrication techniques and the development of sustainable advanced materials to provide solutions for practical applications in dynamic transportation environments. Full article
(This article belongs to the Special Issue Advances in Biomass-Based Materials and Their Applications (2nd Edition))
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17 pages, 6265 KiB  
Article
Co-Doped ErFeO3 for Dual-Band Laser Absorption with High-Temperature Stability
by Rui Liu, Linghao Pan, Fanqi Meng, Xia Feng, Qitu Zhang, Yi Hou and Lixi Wang
Materials 2025, 18(8), 1861; https://doi.org/10.3390/ma18081861 - 18 Apr 2025
Viewed by 110
Abstract
The development of multi-band laser suppression materials has been driven by the limitations of single-band laser suppression materials. Inorganic ceramic materials, compared with organic laser suppression materials, photonic crystals, and metamaterials, offer significant advantages in fabrication methods and environmental stability. In this study, [...] Read more.
The development of multi-band laser suppression materials has been driven by the limitations of single-band laser suppression materials. Inorganic ceramic materials, compared with organic laser suppression materials, photonic crystals, and metamaterials, offer significant advantages in fabrication methods and environmental stability. In this study, Co3+ ions, with relatively higher electronegativity, were introduced to substitute some Fe ion sites in ErFeO3. This substitution caused distortion in the crystal structure, reduced the unit cell volume, and altered the band structure. As a result, the band gap was reduced compared with that of ErFeO3, and the unique energy level transitions of Er ions were activated. This led to dual-band laser suppression with reflectances of 22.16% at 1064 nm and 35.63% at 1540 nm. Furthermore, after high-temperature testing at 1100 °C in air, the laser absorption performance could still be maintained with the intensity retention above 95%. This unique strategy for improving the band structure provides significant potential for applications in laser suppression. Full article
(This article belongs to the Special Issue Application and Theoretical Research of Perovskite Structural Materials)
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