Materials最新文献

{"title":"Wettability Study of Soldered Joints in SiC Ceramics and Combined Ni-SiC Using SnSbTi-Based Solder and Electron Beam Heating.","authors":"Tomas Melus, Roman Kolenak, Jaromir Drapala, Peter Gogola, Matej Pasak, Daniel Drimal, Mikulas Sloboda","doi":"10.3390/ma18122814","DOIUrl":"10.3390/ma18122814","url":null,"abstract":"<p><p>The reactive soldering of silicon-carbide (SiC) ceramics to a Ni-SiC composite was investigated using an Sn-5Sb-3Ti active solder and electron-beam heating at 750 °C, 850 °C and 950 °C. Wettability: The average contact angle decreased from 94 ± 4° (750 °C) to 60 ± 3° (850 °C) and further to 24 ± 2° (950 °C), demonstrating progressively improved spreading of the filler with increasing temperature. Interfacial reactions: Continuous layers of Ni₃(Sn,Sb)₄ and Ti₆(Sn,Sb)₅ formed along the Ni-SiC/filler interface, the latter confirming Ti diffusion that activates the wetting of the composite surface. Mechanical performance: Shear-lap tests on three joints per condition yielded 39 ± 6 MPa (750 °C), 27 ± 2 MPa (850 °C) and 36 ± 15 MPa (950 °C). The highest and lowest individual values at 950 °C were 51 MPa and 21 MPa, respectively. These results show that a higher soldering temperature lowers the contact angle and promotes interfacial reaction, but only a moderate improvement in average joint strength is obtained. These findings demonstrate a flux-free route to bond SiC ceramics with Ni-SiC composites, which is highly relevant for next-generation power-electronics modules and other high-temperature applications.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195365/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Combined MgO Expansive Agent and Rice Husk Ash on Deformation and Strength of Post-Cast Concrete.","authors":"Feifei Jiang, Yijiang Xing, Wencong Deng, Qi Wang, Jialei Wang, Zhongyang Mao","doi":"10.3390/ma18122815","DOIUrl":"10.3390/ma18122815","url":null,"abstract":"<p><p>This study investigates the effects of the combined addition of MgO expansive agent (MEA) and rice husk ash (RHA) on the performance of concrete. Results show that MEA absorbs water and competes with superplasticizers for adsorption, reducing early-age fluidity. In the later stages, its reaction with RHA generates M-S-H gel, accelerating slump loss. At early ages (up to 7 days), due to the slow hydration of MEA and partial replacement of cement, fewer hydration products are formed. Additionally, the pozzolanic reaction of RHA has not yet developed, resulting in the low early strength of concrete. In the later stages, Mg(OH)₂ fills pores and enhances compactness, while the pozzolanic reaction of RHA further optimizes the pore structure. The internal curing effect also provides the moisture needed for continued MEA hydration, significantly improving later-age strength. Moreover, in the post-cast strip of a tall building, the internal curing effect of RHA ensures the effective shrinkage compensation by MEA under low water-to-cement ratio conditions. The restraint provided by reinforcement enhances the pore-filling effect of Mg(OH)₂, improving concrete compactness and crack resistance, ultimately boosting long-term strength and durability.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195257/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On Predicting Optimal Structural Topologies in the Presence of Random Loads.","authors":"Bogdan Bochenek, Katarzyna Tajs-Zielińska","doi":"10.3390/ma18122819","DOIUrl":"10.3390/ma18122819","url":null,"abstract":"<p><p>Topology optimization has been present in modern engineering for several decades, becoming an important tool for solving design problems. Today, it is difficult to imagine progress in engineering design without the search for new approaches to the generation of optimal structural topologies and the development of efficient topological optimization algorithms. The generation of topologies for structures under random loads is one of many research problems where topology optimization is present. It is important to predict the topologies of structures in the case of load uncertainty, since random load changes can significantly affect resulting topologies. This paper proposes an easy-to-implement numerical approach that allows the prediction of the resulting topologies of structures. The basic idea is to transform a random loads case into the deterministic problem of multiple loads. The concept of equivalent load scheme (ELS) is introduced. Instead of generating hundreds of loads applied at random, the selection of a few representative load cases allows the reduction of the numerical effort of the computations. The numerical implementation of proposed concepts is based on the cellular automaton mimicking colliding bodies, which has been recently introduced as an efficient structural topology generator. The examples of topology optimization under randomly applied loads, performed for both plane and spatial structures, have been selected to illustrate the proposed concepts. Confirmed by results of numerical simulations, the efficiency, versatility and ease of implementation of the proposed concept can make an original contribution to research in topological optimization under loads applied in a random manner.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195034/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of Low-Salt-Rejection Membrane by Sodium Hypochlorite Chlorination for Concentration of Low-Concentration Magnesium Chloride Solution.","authors":"Zhengyang Wu, Zongyu Feng, Longsheng Zhao, Zheng Li, Meng Wang, Chao Xia","doi":"10.3390/ma18122824","DOIUrl":"10.3390/ma18122824","url":null,"abstract":"<p><p>The precipitation process of rare earth from a rare earth chloride solution using magnesium bicarbonate yields a dilute magnesium chloride (MgCl₂) solution. The dilute MgCl₂ solution can only be concentrated to a maximum concentration of about 70 g/L by conventional reverse osmosis (RO), which is insufficient for recycling. Low-salt-rejection reverse osmosis (LSRRO) allows for a higher concentration of brine while operating at moderate pressures. However, research on LSRRO for the concentration of MgCl₂ solution is still at an initial stage. In this study, polyamide RO membranes were treated with sodium hypochlorite (NaClO) to prepare low-salt-rejection membranes. The effects of NaClO concentration, pH, and chlorination time on the membrane properties were investigated. Under alkaline chlorination conditions, the membrane's salt rejection decreased, and water flux increased with increasing NaClO concentration and chlorination time. This can be explained by the hydrolysis of polyamide in the alkaline solution to form carboxylic acids and amines, resulting in a decrease in the crosslinking degree of polyamide. The low-salt-rejection membrane was prepared by exposing it to a NaClO solution at a concentration of 15 g/L and a pH of 11 for 3 h, and the salt rejection of MgCl₂ was 50.7%. The MgCl₂ solution with a concentration of 20 g/L was concentrated using multi-stage LSRRO at the pressure of 5 MPa. The concentration of the concentrated brine reached 120 g/L, which is 87% higher than the theoretical maximum concentration of 64 g/L for conventional RO at the pressure of 5 MPa. The specific energy consumption (SEC) was 4.17 kWh/m³, which decreased by about 80% compared to that of mechanical vapor recompression (MVR). This provides an alternative route for the efficient concentration of a diluted MgCl₂ solution with lower energy consumption.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12194825/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Road Map for the Use of Electron Spin Resonance Spectroscopy in the Study of Functionalized Magnetic Nanoparticles.","authors":"Tomasz Kubiak, Bernadeta Dobosz","doi":"10.3390/ma18122841","DOIUrl":"10.3390/ma18122841","url":null,"abstract":"<p><p>Electron paramagnetic resonance (EPR) spectroscopy is gaining increasing recognition in research on various nanostructures. In the case of iron oxide nanoparticles, EPR measurements offer the possibility of determining the magnetic phase and the exact type (Fe₃O₄, γ-Fe₂O₃, α-Fe₂O₃, or a combination) of the core material. Furthermore, the EPR technique enables the study of relaxation processes, estimation of the effective and surface anisotropy constants, and assessment of the influence of sample aging on the magnetic properties of nanoparticles. The scope of the information obtained can be further expanded by utilizing spin labeling of polymer-coated nanoparticles. By analyzing the signals from the attached nitroxide, one can determine certain properties of the coating and its interactions with the environment (e.g., body fluids, cells, tissues) and also perform imaging of nanoparticles in various media. In some cases, EPR can help monitor the encapsulation of active substances and their release processes. Unfortunately, despite the enormous potential, not all of the possibilities offered by EPR are routinely used in nanoscience. Therefore, the present article aims not only to present the current applications and existing trends but also to indicate directions for future EPR research, constituting a road map.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195418/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Crack Cause of Parking Ratchet During the Manufacturing Process.","authors":"Haomin Fan, Xiaochun Xie, Jing Hu, Dandan Wang, Xulong An, Xiangkui Liu, Kunxia Wei, Wei Wei","doi":"10.3390/ma18122821","DOIUrl":"10.3390/ma18122821","url":null,"abstract":"<p><p>The parking ratchet is an important safety component of the car. Cracking occurs in the grinding surface during quenching and grinding processes after carburizing; thus, the goal of this research is to clarify the key cracking cause of the parking ratchet. Optical microscopy (OM), scan electronic microscope (SEM), energy dispersive spectroscopy (EDS), X-ray stress analyzer, etc., were used to systematically test and analyze the cracking cause. The results show that the microstructure of the parking ratchet with cracks after carburizing and quenching is normal, the residual stress of the surface is normal, with no oxide and decarburized layer within the crack areas, without burning during grinding, while it was found that oxide inclusions existed on the area of the crack, which is different from the normal specimens. Hence, a conclusion can be drawn that the cracking cause on the surface of the parking ratchet results from the oxide inclusions in the raw material. This study provides a feasible direction for the failure analysis and control of the cracks on parking ratchets during the manufacturing process.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195382/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical and Early Long-Term Property Assessment of Foamed 3D-Printable Geopolymer Composite.","authors":"Rihards Gailitis, Liga Radina, Leonids Pakrastins, Andina Sprince","doi":"10.3390/ma18122837","DOIUrl":"10.3390/ma18122837","url":null,"abstract":"<p><p>Additive manufacturing has been of considerable interest for the last 10 years. Cementitious composites have been developed to ensure fast and effective structure printing. To address sustainability and reduce the environmental impact of Portland cement-based composites, geopolymer composites have been developed that can be printed. This brings us to this study's aim, which is to allow the printing of recycled lightweight structures with not only the ability to act as a structural material but also insulation capabilities. This study focuses on mix design development and the mechanical strength, creep, and shrinkage properties of these composites. The results show that foamed 3D-printed fly ash-based geopolymer composites may have reduced compressive strength, but still have sufficient strength to be used as a structural material. Furthermore, their creep and shrinkage strain are lower than those of the composite without foaming agent introduction.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195518/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Pulsed Electromagnetic Field Device for Rapid Structural Health Monitoring: Enhanced Joint Integrity Assessment in Steel Structures.","authors":"Viktors Mironovs, Yulia Usherenko, Vjaceslavs Zemcenkovs, Viktors Kurtenoks, Vjaceslavs Lapkovskis, Dmitrijs Serdjuks, Pavels Stankevics","doi":"10.3390/ma18122831","DOIUrl":"10.3390/ma18122831","url":null,"abstract":"<p><p>This study investigates a novel pulsed electromagnetic field (PEMF) device for dynamic testing and structural health monitoring. The research utilises a PEMF generator CD-1501 with a maximum energy capacity of 0.5 kJ and a flat multifilament coil (IC-1) with a 100 mm diameter. Experiments were conducted on a model steel stand with two joint configurations, using steel plates of 4 mm and 8 mm thickness. The device's efficacy was evaluated through oscillation pattern analysis and spectral characteristics. Results demonstrate the device's ability to differentiate between joint states, with the 4 mm plate configuration showing a 15% reduction in high-frequency components compared to the 8 mm plate. Fundamental resonant frequencies of 3D-printed specimens were observed near 5100 Hz, with Q-factors ranging between 200 and 300. The study also found that a 10% increase in volumetric porosity led to a 7% downward shift in resonant frequencies. The developed PEMF device, operating at 50-230 V and delivering 1-5 pulses per minute, shows promise for rapid, non-destructive monitoring of structural joints. When combined with the coaxial correlation method, the system demonstrates enhanced sensitivity in detecting structural changes, utilising an electrodynamic actuator (10 Hz to 2000 Hz range). This integrated approach offers a 30% improvement in early-stage degradation detection compared to traditional methods.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12194878/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Facile Synthesis of Non-Noble CuFeCo/C Catalysts with High Stability for ORR in PEMFC.","authors":"Ruixia Chu, Hongtao Zhang, Fangyuan Qiu, Wenjun Fu, Wanyou Huang, Runze Li, Zhenyu Li, Xiaoyue Jin, Yan Wang","doi":"10.3390/ma18122826","DOIUrl":"10.3390/ma18122826","url":null,"abstract":"<p><p>Proton exchange membrane fuel cells (PEMFCs) have been widely studied as an efficient and environmentally friendly energy conversion technology in recent years. However, the high cost, easy poisoning and complex synthesis methods of noble metal catalysts have hindered their commercialization. Therefore, in this paper, a non-noble metal composite catalyst CuFeCo/C for the oxygen reduction reaction (ORR) was prepared by using a facile liquid-phase reduction method. The ORR kinetic performance of CuFeCo/C was evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and rotating ring-disk electrode (RRDE) tests. The results show that the oxygen reduction peak of CuFeCo/C appears at about 0.64 V, the half-wave potential is about 0.73 V, the limiting current density is about -16.51 A·m^-2, and the Tafel slope is about -0.08. The 10,800 s chronoamperometry test shows that the catalyst has a very good long-term cycle stability. This indicates that the CuFeCo/C composite catalyst has strong stability, good conductivity and ORR catalytic activity under alkaline conditions, which can promote the large-scale commercial application of PEMFCs.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12195301/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Regional Differences in Asphalt Binder Under All-Weather Aging Based on Rheological and Chemical Properties.","authors":"Meng Guo, Yixiang Dong, Xu Yin, Mingyang Guan, Meichen Liang, Xudong Wang, Xiuli Du","doi":"10.3390/ma18122829","DOIUrl":"10.3390/ma18122829","url":null,"abstract":"<p><p>Asphalt binder aging under natural exposure critically determines pavement durability, though current research inadequately captured performance evolution across diverse regional climates. This study investigated climate-driven degradation mechanisms through 12-month all-weather aging (AWA) tests in Gansu, Shandong, and Beijing via rheological (<i>G-R</i> parameter, stiffness modulus <i>S</i>-value) and chemical analyses (carbonyl index <i>I</i>_C=O, sulfoxide index <i>I</i>_S=O). The results demonstrated significant region-dependent aging disparities beyond laboratory simulation. In Gansu, extreme thermal fluctuations and UV radiation accelerated hardening via thermal stress cycles and photo-oxidation, yielding 52.4% higher <i>G-R</i> parameter than PAV. In Shandong, humid saline environments triggered sulfur oxidation-driven electrochemical corrosion, increasing <i>I</i>_S=O by 4.2% compared to PAV. In Beijing, synergistic UV-thermal oxidation elevated <i>I</i>_C=O and <i>S</i>-value by 8% and 40.7%, respectively versus PAV. Critically, <i>I</i>_C=O exhibited strong positive correlations with rheological degradation across regions (r > 0.90, <i>p</i> < 0.01). Based on <i>I</i>_C=O, the 12-month all-weather aging rate in Beijing exceeded Gansu and Shandong by 18.5% and 68%, revealing UV-thermal coupling as the most severe degradation pattern. Novelty lies in quantifying region-specific multi-factor coupling effects (UV-thermal, hygrothermal-salt, etc.) and demonstrating their superior severity over PAV (Beijing > Gansu > Shandong). Dominant environmental factors showed distinct regional variations: UV radiation and temperature difference dominated in Gansu (<i>I</i>_C=O, r = 0.76) and Beijing (0.74), while precipitation-<i>I</i>_C=O correlation prevailed in Shandong (0.76), yet multi-factor coupling ultimately governed aging. These findings provide theoretical foundations for region-tailored and climate-resilient asphalt pavement design.</p>","PeriodicalId":18281,"journal":{"name":"Materials","volume":"18 12","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12194984/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}