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Materials, Volume 17, Issue 9 (May-1 2024) – 237 articles

Cover Story (view full-size image): In this review, the current state of development of metal oxides functionalized with single-atom catalysts (SACs) for gas-sensitive applications were reviewed. Single-atom catalysts (SACs) have gained increasing attention in the field of gas sensing with the advantages of maximized atomic utilization and unique electronic and chemical properties. This review comprehensively elaborates the principles of single atoms from preparation to application, as well as summarizing the latest developments in gas sensing. View this paper
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14 pages, 2922 KiB  
Article
A Study on the Materials Used in Ancient Wooden Architectural Paintings at DaZhong Gate in Confucius Temple, Qufu, Shandong, China
by Kuiju Li, Kezhu Han, Gele Teri, Yuxiao Tian, Menglei Cui, Yunpeng Qi and Yuhu Li
Materials 2024, 17(9), 2170; https://doi.org/10.3390/ma17092170 - 6 May 2024
Viewed by 538
Abstract
This study analyzes the pigments and binders used in the painted wooden structure of DaZhong Gate in the Confucius Temple in Qufu, Shandong Province, China. Five samples were collected from the building and analyzed using techniques such as polarized light microscopy (PLM), energy-dispersive [...] Read more.
This study analyzes the pigments and binders used in the painted wooden structure of DaZhong Gate in the Confucius Temple in Qufu, Shandong Province, China. Five samples were collected from the building and analyzed using techniques such as polarized light microscopy (PLM), energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy (m-RS), and Fourier-transform infrared spectroscopy (FT-IR). The findings reveal that the red, yellow, green, and blue pigments are identified as lead red, lead chromate yellow, emerald green, and ultramarine, respectively. The white pigment is determined to be a combination of chalk and lead white or anglesite. Considering the production period of the yellow and green pigments, it is inferred that architectural paintings underwent restoration or repainting during the late Qing Dynasty. The analysis of the binder in the pigment using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) reveals that the binder employed is a protein-based glue. Additionally, the detected presence of Heat-bodied tung oil suggests a potential connection to traditional Chinese painting techniques on wooden surfaces. This discovery not only contributes to the historical research of the Confucius Temple but also provides crucial data for the conservation and restoration efforts of this culturally significant heritage site. Full article
(This article belongs to the Topic Advances in Non-Destructive Testing Methods, 2nd Volume)
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26 pages, 10114 KiB  
Review
Waste Glass Upcycling Supported by Alkali Activation: An Overview
by Muhammad Jamshaid Zafar, Hamada Elsayed and Enrico Bernardo
Materials 2024, 17(9), 2169; https://doi.org/10.3390/ma17092169 - 6 May 2024
Viewed by 575
Abstract
Alkali-activated materials are gaining much interest due to their outstanding performance, including their great resistance to chemical corrosion, good thermal characteristics, and ability to valorise industrial waste materials. Reusing waste glasses in creating alkali-activated materials appears to be a viable option for more [...] Read more.
Alkali-activated materials are gaining much interest due to their outstanding performance, including their great resistance to chemical corrosion, good thermal characteristics, and ability to valorise industrial waste materials. Reusing waste glasses in creating alkali-activated materials appears to be a viable option for more effective solid waste utilisation and lower-cost products. However, very little research has been conducted on the suitability of waste glass as a prime precursor for alkali activation. This study examines the reuse of seven different types of waste glasses in the creation of geopolymeric and cementitious concretes as sustainable building materials, focusing in particular on how using waste glasses as the raw material in alkali-activated materials affects the durability, microstructures, hydration products, and fresh and hardened properties in comparison with using traditional raw materials. The impacts of several vital parameters, including the employment of a chemical activator, gel formation, post-fabrication curing procedures, and the distribution of source materials, are carefully considered. This review will offer insight into an in-depth understanding of the manufacturing and performance in promising applications of alkali-activated waste glass in light of future uses. The current study aims to provide a contemporary review of the chemical and structural properties of glasses and the state of research on the utilisation of waste glasses in the creation of alkali-activated materials. Full article
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16 pages, 5880 KiB  
Article
Rust Prevention Property of a New Organic Inhibitor under Different Conditions
by Xingxing Guo, Chengsheng Wang, Hua Fu, Li Tian and Hua Song
Materials 2024, 17(9), 2168; https://doi.org/10.3390/ma17092168 - 6 May 2024
Viewed by 382
Abstract
The corrosion resistance properties of a new type of environmentally-friendly organic inhibitor containing amino ketone molecules are presented in this paper. To evaluate the prevention effect of the inhibitor on corrosion of reinforcement, the electrochemical characteristics of steels in the simulated concrete pore [...] Read more.
The corrosion resistance properties of a new type of environmentally-friendly organic inhibitor containing amino ketone molecules are presented in this paper. To evaluate the prevention effect of the inhibitor on corrosion of reinforcement, the electrochemical characteristics of steels in the simulated concrete pore solution (SPS) were investigated under varied conditions of the relevant parameters, including concentrations of the inhibitor and NaCl, pH value, and temperature. The inhibition efficiency of the material was characterized through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and the weight loss of steels. The results reveal a significant improvement in the corrosion resistance of steels with the inhibitor. A maximum resistance value of 89.07% was achieved at an inhibitor concentration of 4%. Moreover, the new organic inhibitor exhibited good corrosion protection capability for steels under different NaCl concentrations. Its inhibition efficiency was determined to be 65.62, 80.06, and 66.30% at NaCl concentrations of 2, 3.5 and 5%, respectively. On the other hand, it was found that an alkaline environment was favorable for an enhanced corrosion prevention effect, and an optimal pH value of 11.3 was observed in this work. Besides, the inhibition efficiencies at different temperatures showed a trend of 25 > 35 > 40 > 20 > 30 °C, with a maximum value of 81.32% at 25 °C. The above results suggest that the new organic material has high potential to be used as an eco-friendly and long-term durable inhibitor for steel corrosion prevention under complex conditions. Full article
(This article belongs to the Special Issue Corrosion Mechanism and Protection Technology of Metallic Materials)
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37 pages, 21095 KiB  
Article
Artificial Neural Networks and Experimental Analysis of the Resistance Spot Welding Parameters Effect on the Welded Joint Quality of AISI 304
by Marwan T. Mezher, Alejandro Pereira, Tomasz Trzepieciński and Jorge Acevedo
Materials 2024, 17(9), 2167; https://doi.org/10.3390/ma17092167 - 6 May 2024
Viewed by 628
Abstract
The automobile industry relies primarily on spot welding operations, particularly resistance spot welding (RSW). The performance and durability of the resistance spot-welded joints are significantly impacted by the welding quality outputs, such as the shear force, nugget diameter, failure mode, and the hardness [...] Read more.
The automobile industry relies primarily on spot welding operations, particularly resistance spot welding (RSW). The performance and durability of the resistance spot-welded joints are significantly impacted by the welding quality outputs, such as the shear force, nugget diameter, failure mode, and the hardness of the welded joints. In light of this, the present study sought to determine how the aforementioned welding quality outputs of 0.5 and 1 mm thick austenitic stainless steel AISI 304 were affected by RSW parameters, such as welding current, welding time, pressure, holding time, squeezing time, and pulse welding. In order to guarantee precise evaluation and experimental analysis, it is essential that they are supported by a numerical model using an intelligent model. The primary objective of this research is to develop and enhance an intelligent model employing artificial neural network (ANN) models. This model aims to provide deeper knowledge of how the RSW parameters affect the quality of optimum joint behavior. The proposed neural network (NN) models were executed using different ANN structures with various training and transfer functions based on the feedforward backpropagation approach to find the optimal model. The performance of the ANN models was evaluated in accordance with validation metrics, like the mean squared error (MSE) and correlation coefficient (R2). Assessing the experimental findings revealed the maximum shear force and nugget diameter emerged to be 8.6 kN and 5.4 mm for the case of 1–1 mm, 3.298 kN and 4.1 mm for the case of 0.5–0.5 mm, and 4.031 kN and 4.9 mm for the case of 0.5–1 mm. Based on the results of the Pareto charts generated by the Minitab program, the most important parameter for the 1–1 mm case was the welding current; for the 0.5–0.5 mm case, it was pulse welding; and for the 0.5–1 mm case, it was holding time. When looking at the hardness results, it is clear that the nugget zone is much higher than the heat-affected zone (HZ) and base metal (BM) in all three cases. The ANN models showed that the one-output shear force model gave the best prediction, relating to the highest R and the lowest MSE compared to the one-output nugget diameter model and two-output structure. However, the Levenberg–Marquardt backpropagation (Trainlm) training function with the log sigmoid transfer function recorded the best prediction results of both ANN structures. Full article
(This article belongs to the Special Issue Advanced Materials and Manufacturing Processes)
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15 pages, 3908 KiB  
Article
Deep Learning-Based Design Method for Acoustic Metasurface Dual-Feature Fusion
by Qiang Lv, Huanlong Zhao, Zhen Huang, Guoqiang Hao and Wei Chen
Materials 2024, 17(9), 2166; https://doi.org/10.3390/ma17092166 - 6 May 2024
Viewed by 556
Abstract
Existing research in metasurface design was based on trial-and-error high-intensity iterations and requires deep acoustic expertise from the researcher, which severely hampered the development of the metasurface field. Using deep learning enabled the fast and accurate design of hypersurfaces. Based on this, in [...] Read more.
Existing research in metasurface design was based on trial-and-error high-intensity iterations and requires deep acoustic expertise from the researcher, which severely hampered the development of the metasurface field. Using deep learning enabled the fast and accurate design of hypersurfaces. Based on this, in this paper, an integrated learning approach was first utilized to construct a model of the forward mapping relationship between the hypersurface physical structure parameters and the acoustic field, which was intended to be used for data enhancement. Then a dual-feature fusion model (DFCNN) based on a convolutional neural network was proposed, in which the first feature was the high-dimensional nonlinear features extracted using a data-driven approach, and the second feature was the physical feature information of the acoustic field mined using the model. A convolutional neural network was used for feature fusion. A genetic algorithm was used for network parameter optimization. Finally, generalization ability verification was performed to prove the validity of the network model. The results showed that 90% of the integrated learning models had an error of less than 3 dB between the real and predicted sound field data, and 93% of the DFCNN models could achieve an error of less than 5 dB in the local sound field intensity. Full article
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11 pages, 4421 KiB  
Article
Transformation of Coherent Twin Boundary into Basal-Prismatic Boundary in HCP-Ti: A Molecular Dynamics Study
by Tao Sun, Qili Bao, Yang Gao, Shujun Li, Jianping Li and Hao Wang
Materials 2024, 17(9), 2165; https://doi.org/10.3390/ma17092165 - 6 May 2024
Viewed by 398
Abstract
The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains [...] Read more.
The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains with ~90° misorientation: the basal/prismatic boundary (BPB) and the coherent twin boundary (CTB). The mechanical response of the BPB and CTB under external loading was studied through molecular dynamic simulations of HCP-Ti. The results revealed that CTB undergoes transformation into BPB through the accumulation of twin boundary (TB) steps and subsequent emission of Shockley partial dislocations. When the total mismatch vector is close to the Burgers vector of a Shockley partial dislocation, BPB emits partial dislocations and further grows along the stacking faults. When a pair of CTBs are close to each other, severe boundary distortion occurs, facilitating the emission and absorption of partial dislocations, which further assists the CTB-BPB transformation. The present results thus help to explain the frequent observation of coexisting CTB and BPB in HCP alloys and further contribute to the understanding of their microstructure and property regulation. Full article
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9 pages, 3850 KiB  
Article
Molybdenum-Doped ZnO Thin Films Obtained by Spray Pyrolysis
by Pavlina Bancheva-Koleva, Veselin Zhelev, Plamen Petkov and Tamara Petkova
Materials 2024, 17(9), 2164; https://doi.org/10.3390/ma17092164 - 6 May 2024
Viewed by 453
Abstract
A batch of ZnO thin films, pure and doped with molybdenum (up to 2 mol %), were prepared using the spray pyrolysis technique on glass and silicon substrates. The effect of molybdenum concentration on the morphology, structure and optical properties of the films [...] Read more.
A batch of ZnO thin films, pure and doped with molybdenum (up to 2 mol %), were prepared using the spray pyrolysis technique on glass and silicon substrates. The effect of molybdenum concentration on the morphology, structure and optical properties of the films was investigated. X-ray diffraction (XRD) results show a wurtzite polycrystalline crystal structure. The average crystallite size increases from 30 to 80 nm with increasing molybdenum content. Scanning electron microscopy (SEM) images demonstrate a smooth and homogeneous surface with densely spaced nanocrystalline grains. The number of nuclei increases, growing over the entire surface of the substrate with uniform grains, when the molybdenum concentration is increased to 2 mol %. The estimated root mean square (RMS) roughness values for the undoped and doped with 1 mol % and 2 mol % of ZnO thin films, defined by atomic force microscopy (AFM), are 6.12, 23.54 and 23.83 nm, respectively. The increase in Mo concentration contributes to the increase in film transmittance. Full article
(This article belongs to the Section Thin Films and Interfaces)
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15 pages, 6161 KiB  
Article
Strain-Based Assessment to Evaluate Damage Caused by Deep Rolling
by Tobias Pertoll, Martin Leitner, Christian Buzzi and László Boronkai
Materials 2024, 17(9), 2163; https://doi.org/10.3390/ma17092163 - 6 May 2024
Viewed by 341
Abstract
The positive effects of deep rolling on fatigue strength—reduced surface roughness, work hardening and compressive residual stress—in the near-surface region are achieved by controlled high plasticisation of the treated material. However, excessive and/or repeated plasticising poses a risk of damage to the machined [...] Read more.
The positive effects of deep rolling on fatigue strength—reduced surface roughness, work hardening and compressive residual stress—in the near-surface region are achieved by controlled high plasticisation of the treated material. However, excessive and/or repeated plasticising poses a risk of damage to the machined component. This paper investigates the damage caused by deep rolling of a railway axle. Two sections of the axle are experimentally deep rolled repeatedly at different feed rates until damage is detected. For comparative analysis, these experiments are numerically analysed and the damage is assessed using the strain-based damage calculation. The results are compared and a damage sum of ~120% is evaluated for both tests, thus developing a reliable and conservative assessment method. The single deep rolling treatment at a feed rate of 0.25 mm causes damage of 6.1%, and at a feed rate of 0.5 mm, damage of 4.7%. The developed and experimentally validated evaluation method allows for investigating the limits of applicability of different deep rolling parameters. The influence of the deep rolling force and feed rate and a proposed optimisation with multiple deep rolling with reduced deep rolling forces are investigated. Full article
(This article belongs to the Special Issue Surface Engineering in Materials)
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17 pages, 8971 KiB  
Article
Functionalized γ-Boehmite Covalent Grafting Modified Polyethylene for Lithium-Ion Battery Separator
by Yuanxin Man, Hui Nan, Jianzhe Ma, Zhike Li, Jingyuan Zhou, Xianlan Wang, Heqi Li, Caihong Xue and Yongchun Yang
Materials 2024, 17(9), 2162; https://doi.org/10.3390/ma17092162 - 6 May 2024
Viewed by 528
Abstract
In the field of lithium-ion batteries, the challenges posed by the low melting point and inadequate wettability of conventional polyolefin separators have increased the focus on ceramic-coated separators. This study introduces a highly efficient and stable boehmite/polydopamine/polyethylene (AlOOH-PDA-PE) separator. It is crafted by [...] Read more.
In the field of lithium-ion batteries, the challenges posed by the low melting point and inadequate wettability of conventional polyolefin separators have increased the focus on ceramic-coated separators. This study introduces a highly efficient and stable boehmite/polydopamine/polyethylene (AlOOH-PDA-PE) separator. It is crafted by covalently attaching functionalized nanosized boehmite (γ-AlOOH) whiskers onto polyethylene (PE) surfaces. The presence of a covalent bond increases the stability at the interface, while amino groups on the surface of the separator enhance the infiltration of the electrolyte and facilitate the diffusion of lithium ions. The PE-PDA-AlOOH separator, when used in lithium-ion batteries, achieves a discharge capacity of 126 mAh g−1 at 5 C and retains 97.1% capacity after 400 cycles, indicating superior cycling stability due to its covalently bonded ceramic surface. Thus, covalent interface modification is a promising strategy to prevent delamination of ceramic coatings in separators. Full article
(This article belongs to the Topic Advanced Nanomaterials for Lithium-Ion Batteries)
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10 pages, 4753 KiB  
Article
Stress Distribution within the Peri-Implant Bone for Different Implant Materials Obtained by Digital Image Correlation
by Ragai Edward Matta, Lara Berger, Moritz Loehlein, Linus Leven, Juergen Taxis, Manfred Wichmann and Constantin Motel
Materials 2024, 17(9), 2161; https://doi.org/10.3390/ma17092161 - 6 May 2024
Viewed by 502
Abstract
Stress distribution and its magnitude during loading heavily influence the osseointegration of dental implants. Currently, no high-resolution, three-dimensional method of directly measuring these biomechanical processes in the peri-implant bone is available. The aim of this study was to measure the influence of different [...] Read more.
Stress distribution and its magnitude during loading heavily influence the osseointegration of dental implants. Currently, no high-resolution, three-dimensional method of directly measuring these biomechanical processes in the peri-implant bone is available. The aim of this study was to measure the influence of different implant materials on stress distribution in the peri-implant bone. Using the three-dimensional ARAMIS camera system, surface strain in the peri-implant bone area was compared under simulated masticatory forces of 300 N in axial and non-axial directions for titanium implants and zirconia implants. The investigated titanium implants led to a more homogeneous stress distribution than the investigated zirconia implants. Non-axial forces led to greater surface strain on the peri-implant bone than axial forces. Thus, the implant material, implant system, and direction of force could have a significant influence on biomechanical processes and osseointegration within the peri-implant bone. Full article
(This article belongs to the Special Issue Advanced Dental Materials: From Design to Application)
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14 pages, 5035 KiB  
Article
An Influence of Actuator Gluing on Elastic Wave Excited in the Structure
by Dominika Ziaja and Michał Jurek
Materials 2024, 17(9), 2160; https://doi.org/10.3390/ma17092160 - 6 May 2024
Viewed by 480
Abstract
In this article, the practical issues connected with guided wave measurement are studied: (1) the influence of gluing of PZT plate actuators (NAC2013) on generated elastic wave propagation, (2) the repeatability of PZT transducers attachment, and (3) the assessment of the possibility of [...] Read more.
In this article, the practical issues connected with guided wave measurement are studied: (1) the influence of gluing of PZT plate actuators (NAC2013) on generated elastic wave propagation, (2) the repeatability of PZT transducers attachment, and (3) the assessment of the possibility of comparing the results of Laser Doppler Vibrometry (LDV) measurement performed on different 2D samples. The consideration of these questions is crucial in the context of the assessment of the possibility of the application of the guided wave phenomenon to structural health-monitoring systems, e.g., in civil engineering. In the examination, laboratory tests on the web of steel I-section specimens were conducted. The size and shape of the specimens were developed in such a way that they were similar to the elements typically used in civil engineering structures. It was proved that the highest amplitude of the generated wave was obtained when the exciters were glued using wax. The repeatability and durability of this connection type were the weakest. Due to this reason, it was not suitable for practical use outside the laboratory. The permanent glue application gave a stable connection between the exciter and the specimen, but the generated signal had the lowest amplitude. In the paper, the new procedure dedicated to objective analysis and comparison of the elastic waves propagating on the surface of different specimens was proposed. In this procedure, the genetic algorithms help with the determination of a new coordinate system, in which the assessment of the quality of wave propagation in different directions is possible. Full article
(This article belongs to the Special Issue Nondestructive Evaluation for Comprehensive Material Characterization)
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14 pages, 2181 KiB  
Article
Bond Strength of Milled and Printed Zirconia to 10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP) Resin Cement as a Function of Ceramic Conditioning, Disinfection and Ageing
by Wolfgang Bömicke, Franz Sebastian Schwindling, Peter Rammelsberg and Stefan Rues
Materials 2024, 17(9), 2159; https://doi.org/10.3390/ma17092159 - 5 May 2024
Viewed by 550
Abstract
This study aimed to assess the suitability of printed zirconia (ZrO2) for adhesive cementation compared to milled ZrO2. Surface conditioning protocols and disinfection effects on bond strength were also investigated. ZrO2 discs (n = 14/group) underwent either alumina [...] Read more.
This study aimed to assess the suitability of printed zirconia (ZrO2) for adhesive cementation compared to milled ZrO2. Surface conditioning protocols and disinfection effects on bond strength were also investigated. ZrO2 discs (n = 14/group) underwent either alumina (Al2O3) airborne particle abrasion (APA; 50 µm, 0.10 MPa) or tribochemical silicatisation (TSC; 110 µm Al2O3, 0.28 MPa and 110 µm silica-modified Al2O3, 0.28 MPa), followed by disinfection (1 min immersion in 70% isopropanol, 15 s water spray, 10 s drying with oil-free air) for half of the discs. A resin cement containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) was used for bonding (for TSC specimens after application of a primer containing silane and 10-MDP). Tensile bond strength was measured after storage for 24 h at 100% relative humidity or after 30 days in water, including 7500 thermocycles. Surface conditioning significantly affected bond strength, with higher values for TSC specimens. Ageing and the interaction of conditioning, disinfection and ageing also impacted bond strength. Disinfection combined with APA mitigated ageing-related bond strength decrease but exacerbated it for TSC specimens. Despite these effects, high bond strengths were maintained even after disinfection and ageing. Adhesive cementation of printed ZrO2 restorations exhibited comparable bond strengths to milled ZrO2, highlighting its feasibility in clinical applications. Full article
(This article belongs to the Special Issue Advanced Dental Materials: From Design to Application)
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12 pages, 40630 KiB  
Article
Interfacial Reactions between Sn-Based Solders and n-Type Bi2(Te,Se)3 Thermoelectric Material
by Chao-Hong Wang, Chun-Wei Chiu and Mei-Hau Li
Materials 2024, 17(9), 2158; https://doi.org/10.3390/ma17092158 - 5 May 2024
Viewed by 435
Abstract
This study investigated the interfacial reactions between n-type Bi2(Te,Se)3 thermoelectric material, characterized by a highly-oriented (110) plane, and pure Sn and Sn-3.0Ag-0.5Cu (wt.%) solders, respectively. At 250 °C, the liquid-state Sn/Bi2(Te,Se)3 reactions resulted in the formation of [...] Read more.
This study investigated the interfacial reactions between n-type Bi2(Te,Se)3 thermoelectric material, characterized by a highly-oriented (110) plane, and pure Sn and Sn-3.0Ag-0.5Cu (wt.%) solders, respectively. At 250 °C, the liquid-state Sn/Bi2(Te,Se)3 reactions resulted in the formation of both SnTe and BiTe phases, with Bi-rich particles dispersed within the SnTe phase. The growth of the SnTe phase exhibited diffusion-controlled parabolic behavior over time. In contrast, the growth rate was considerably slower compared to that observed with p-type (Bi,Sb)2Te3. Solid-state Sn/Bi2(Te,Se)3 reactions conducted between 160 °C and 200 °C exhibited similar interfacial microstructures. The SnTe phase remained the primary reaction product, embedded with tiny Bi-rich particles, revealing a diffusion-controlled growth. However, the BiTe layer had no significant growth. Further investigation into growth kinetics of intermetallic compounds and microstructural evolution was conducted to elucidate the reaction mechanism. The slower growth rates in Bi2(Te,Se)3, compared to the reactions with (Bi,Sb)2Te3, could be attributed to the strong suppression effect of Se on SnTe growth. Additionally, the interfacial reactions of Bi2(Te,Se)3 with Sn-3.0Ag-0.5Cu were also examined, showing similar growth behavior to those observed with Sn solder. Notably, compared with Ag, Cu tends to diffuse towards the interfacial reaction phases, resulting in a high Cu solubility within the SnTe phase. Full article
(This article belongs to the Special Issue Welding, Joining, and Additive Manufacturing of Metals and Alloys)
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16 pages, 4235 KiB  
Article
The Impact of Impurity Gases on the Hydrogen Embrittlement Behavior of Pipeline Steel in High-Pressure H2 Environments
by Chengshuang Zhou, Hongbin Zhou and Lin Zhang
Materials 2024, 17(9), 2157; https://doi.org/10.3390/ma17092157 - 5 May 2024
Viewed by 503
Abstract
The use of hydrogen-blended natural gas presents an efficacious pathway toward the rapid, large-scale implementation of hydrogen energy, with pipeline transportation being the principal method of conveyance. However, pipeline materials are susceptible to hydrogen embrittlement in high-pressure hydrogen environments. Natural gas contains various [...] Read more.
The use of hydrogen-blended natural gas presents an efficacious pathway toward the rapid, large-scale implementation of hydrogen energy, with pipeline transportation being the principal method of conveyance. However, pipeline materials are susceptible to hydrogen embrittlement in high-pressure hydrogen environments. Natural gas contains various impurity gases that can either exacerbate or mitigate sensitivity to hydrogen embrittlement. In this study, we analyzed the mechanisms through which multiple impurity gases could affect the hydrogen embrittlement behavior of pipeline steel. We examined the effects of O2 and CO2 on the hydrogen embrittlement behavior of L360 pipeline steel through a series of fatigue crack growth tests conducted in various environments. We analyzed the fracture surfaces and assessed the fracture mechanisms involved. We discovered that CO2 promoted the hydrogen embrittlement of the material, whereas O2 inhibited it. O2 mitigated the enhancing effect of CO2 when both gases were mixed with hydrogen. As the fatigue crack growth rate increased, the influence of impurity gases on the hydrogen embrittlement of the material diminished. Full article
(This article belongs to the Section Metals and Alloys)
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18 pages, 13276 KiB  
Article
Microstructural Investigation of Process Parameters Dedicated to Laser Powder Bed Fusion of AlSi7Mg0.6 Alloy
by Janusz Kluczyński, Tomáš Dražan, Zdeněk Joska, Jakub Łuszczek, Robert Kosturek and Katarzyna Jasik
Materials 2024, 17(9), 2156; https://doi.org/10.3390/ma17092156 - 5 May 2024
Viewed by 380
Abstract
This study presents a microstructural investigation of the printing parameters of an AlSi7Mg0.6 alloy produced by powder bed fusion (PBF) using laser beam melting (LB/M) technology. The investigation focused on the effects of laser power, exposure velocity, and hatching distance on the microhardness, [...] Read more.
This study presents a microstructural investigation of the printing parameters of an AlSi7Mg0.6 alloy produced by powder bed fusion (PBF) using laser beam melting (LB/M) technology. The investigation focused on the effects of laser power, exposure velocity, and hatching distance on the microhardness, porosity, and microstructure of the produced alloy. The microstructure was characterized in the plane of printing on a confocal microscope. The results showed that the printing parameters significantly affected the microstructure, whereas the energy density had a major effect. Decreasing the laser power and decreasing the hatching distance resulted in increased porosity and the increased participation of non-melted particles. A mathematical model was created to determine the porosity of a 3D-printed material based on three printing parameters. Microhardness was not affected by the printing parameters. The statistical model created based on the porosity investigation allowed for the illustration of the technological window and showed certain ranges of parameter values at which the porosity of the produced samples was at a possible low level. Full article
(This article belongs to the Special Issue Laser Technology for Materials Processing)
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13 pages, 6713 KiB  
Article
Microstructure and Properties of Pressureless-Sintered Zirconium Carbide Ceramics with MoSi2 Addition
by Xiuzheng Chen, Haibo Wu, Huan Liu, Yitian Yang, Bingbing Pei, Jianshen Han, Zehua Liu, Xishi Wu and Zhengren Huang
Materials 2024, 17(9), 2155; https://doi.org/10.3390/ma17092155 - 5 May 2024
Viewed by 336
Abstract
Zirconium carbide (ZrC) ceramics have a high melting point, low neutron absorption cross section, and excellent resistance to the impact of fission products and are considered to be one of the best candidate materials for fourth-generation nuclear energy systems. ZrC ceramics with a [...] Read more.
Zirconium carbide (ZrC) ceramics have a high melting point, low neutron absorption cross section, and excellent resistance to the impact of fission products and are considered to be one of the best candidate materials for fourth-generation nuclear energy systems. ZrC ceramics with a high relative density of 99.1% were successfully prepared via pressureless sintering using a small amount of MoSi2 as an additive. The influence of the MoSi2 content on the densification behavior, microstructure, mechanical properties, and thermal properties of ZrC ceramics was systematically investigated. The results show that the densification of ZrC was significantly enhanced by the introduction of MoSi2 due to the formation of a liquid phase during sintering. In addition, the ZrC grains were refined due to the pinning effect of the generated silicon carbide. The flexural strength and Vickers hardness of ZrC ceramics with 2.5 vol% MoSi2 sintered at 1850 °C were 408 ± 12 MPa and 17.1 GPa, respectively, which were approximately 30% and 10% higher compared to the samples without the addition of MoSi2. The improved mechanical properties were mainly attributed to the high relative density (99.1%) and refined microstructure. Full article
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16 pages, 9832 KiB  
Article
Effect of ZnO on Luminescence Performance of Terbium-Activated Zinc Borosilicate Glasses
by Sena Dayioglugil and Nuri Solak
Materials 2024, 17(9), 2154; https://doi.org/10.3390/ma17092154 - 4 May 2024
Viewed by 524
Abstract
In this study, terbium-doped ZnO-SiO2-B2O3-Na2O glasses were fabricated with the conventional melt-quenching method. The effect of altering the concentration of the host matrix on luminescence performance was investigated in terms of different ZnO/B2O [...] Read more.
In this study, terbium-doped ZnO-SiO2-B2O3-Na2O glasses were fabricated with the conventional melt-quenching method. The effect of altering the concentration of the host matrix on luminescence performance was investigated in terms of different ZnO/B2O3 and ZnO/SiO2 ratios. FT-IR results indicate that bridging oxygens (Bos) were converted to non-bridging oxygens (NBOs) with increments of ZnO. Furthermore, the emission intensity and luminescence lifetime of samples were influenced by the amount of ZnO; this was proven with photoluminescence spectra results. The maximum emission intensity was observed at a 1.1 ZnO/B2O3 ratio and a 0.8 ZnO/SiO2 ratio; however, the highest luminescence lifetime was observed at a 1.1 ZnO/SiO2 ratio. The emission intensity and luminescence lifetime of glass samples were improved by heat treatment as a result of the formation of willemite and zinc oxide phases. An increase in the ZnO/SiO2 ratio facilitated the formation of willemite and zinc oxide phases; therefore, crystallinity was directly related to the luminescence behavior of glass samples. Full article
(This article belongs to the Special Issue Structural and Luminescence Properties of Glass)
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16 pages, 4950 KiB  
Article
Analysis of Mechanical Properties of Fiber-Reinforced Soil Cement Based on Kaolin
by Junnan Zhao, Zhongling Zong, Hang Cen and Pai Jiang
Materials 2024, 17(9), 2153; https://doi.org/10.3390/ma17092153 - 4 May 2024
Viewed by 424
Abstract
Adding fibers into cement to form fiber-reinforced soil cement material can effectively enhance its physical and mechanical properties. In order to investigate the effect of fiber type and dosage on the strength of fiber-reinforced soil cement, polypropylene fibers (PPFs), polyvinyl alcohol fibers (PVAFs), [...] Read more.
Adding fibers into cement to form fiber-reinforced soil cement material can effectively enhance its physical and mechanical properties. In order to investigate the effect of fiber type and dosage on the strength of fiber-reinforced soil cement, polypropylene fibers (PPFs), polyvinyl alcohol fibers (PVAFs), and glass fibers (GFs) were blended according to the mass fraction of the mixture of cement and dry soil (0.5%, 1%, 1.5%, and 2%). Unconfined compressive strength tests, split tensile strength tests, scanning electron microscopy (SEM) tests, and mercury intrusion porosimetry (MIP) pore structure analysis tests were conducted. The results indicated that the unconfined compressive strength of the three types of fiber-reinforced soil cement peaked at a fiber dosage of 0.5%, registering 26.72 MPa, 27.49 MPa, and 27.67 MPa, respectively. The split tensile strength of all three fiber-reinforced soil cement variants reached their maximum at a 1.5% fiber dosage, recording 2.29 MPa, 2.34 MPa, and 2.27 MPa, respectively. The predominant pore sizes in all three fiber-reinforced soil cement specimens ranged from 10 nm to 100 nm. Furthermore, analysis from the perspective of energy evolution revealed that a moderate fiber dosage can minimize energy loss. This paper demonstrates that the unconfined compressive strength test, split tensile strength test, scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) pore structure analysis offer theoretical underpinnings for the utilization of fiber-reinforced soil cement in helical pile core stiffening and broader engineering applications. Full article
(This article belongs to the Section Construction and Building Materials)
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40 pages, 3846 KiB  
Review
Quantum Dot Research in Breast Cancer: Challenges and Prospects
by Hossein Omidian, Renae L. Wilson and Luigi X. Cubeddu
Materials 2024, 17(9), 2152; https://doi.org/10.3390/ma17092152 - 4 May 2024
Viewed by 533
Abstract
The multifaceted role of quantum dots (QDs) in breast cancer research highlights significant advancements in diagnostics, targeted therapy, and drug delivery systems. This comprehensive review addresses the development of precise imaging techniques for early cancer detection and the use of QDs in enhancing [...] Read more.
The multifaceted role of quantum dots (QDs) in breast cancer research highlights significant advancements in diagnostics, targeted therapy, and drug delivery systems. This comprehensive review addresses the development of precise imaging techniques for early cancer detection and the use of QDs in enhancing the specificity of therapeutic delivery, particularly in challenging cases like triple-negative breast cancer (TNBC). The paper also discusses the critical understanding of QDs’ interactions with cancer cells, offering insights into their potential for inducing cytotoxic effects and facilitating gene therapy. Limitations such as biocompatibility, toxicity concerns, and the transition from laboratory to clinical practice are critically analyzed. Future directions emphasize safer, non-toxic QD development, improved targeting mechanisms, and the integration of QDs into personalized medicine, aiming to overcome the current challenges and enhance breast cancer management. Full article
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16 pages, 15116 KiB  
Article
Impact of Hydrostatic Pressure on Molecular Structure and Dynamics of the Sodium and Chloride Ions in Portlandite Nanopores
by Run Zhang, Hongping Zhang, Meng Chen, Laibao Liu, Hongbin Tan and Youhong Tang
Materials 2024, 17(9), 2151; https://doi.org/10.3390/ma17092151 - 4 May 2024
Viewed by 416
Abstract
In order to address the issues of energy depletion, more resources are being searched for in the deep sea. Therefore, research into how the deep-sea environment affects cement-based materials for underwater infrastructure is required. This paper examines the impact of ocean depth (0, [...] Read more.
In order to address the issues of energy depletion, more resources are being searched for in the deep sea. Therefore, research into how the deep-sea environment affects cement-based materials for underwater infrastructure is required. This paper examines the impact of ocean depth (0, 500, 1000, and 1500 m) on the ion interaction processes in concrete nanopores using molecular dynamics simulations. At the portlandite interface, the local structural and kinetic characteristics of ions and water molecules are examined. The findings show that the portlandite surface hydrophilicity is unaffected by increasing depth. The density profile and coordination number of ions alter as depth increases, and the diffusion speed noticeably decreases. The main cause of the ions’ reduced diffusion velocity is expected to be the low temperature. This work offers a thorough understanding of the cement hydration products’ microstructure in deep sea, which may help explain why cement-based underwater infrastructure deteriorates over time. Full article
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10 pages, 3506 KiB  
Article
Effect of Cu Film Thickness on Cu Bonding Quality and Bonding Mechanism
by Tsan-Feng Lu, Kai-Ning Hsu, Ching-Chi Hsu, Chia-Yu Hsu and YewChung Sermon Wu
Materials 2024, 17(9), 2150; https://doi.org/10.3390/ma17092150 - 4 May 2024
Cited by 1 | Viewed by 411
Abstract
In the hybrid bonding process, the final stage of chemical mechanical polishing plays a critical role. It is essential to ensure that the copper surface is recessed slightly from the oxide surface. However, this recess can lead to the occurrence of interfacial voids [...] Read more.
In the hybrid bonding process, the final stage of chemical mechanical polishing plays a critical role. It is essential to ensure that the copper surface is recessed slightly from the oxide surface. However, this recess can lead to the occurrence of interfacial voids between the bonded copper interfaces. To examine the effects of copper film thickness on bonding quality and bonding mechanisms in this study, artificial voids were intentionally introduced at the bonded interfaces at temperatures of 250 °C and 300 °C. The results revealed that as the thickness of the copper film increases, there is an increase in the bonding fraction and a decrease in the void fraction. The variations in void height with different copper film thicknesses were influenced by the bonding mechanism and bonding fraction. Full article
(This article belongs to the Special Issue Welding, Joining, and Additive Manufacturing of Metals and Alloys)
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15 pages, 7671 KiB  
Article
Comparative Study of the Impurity Effect on SnAgCu and SnZn Solder Joints with Electrodeposited Cu
by Yu-Ju Li, Yee-Wen Yen and Chih-Ming Chen
Materials 2024, 17(9), 2149; https://doi.org/10.3390/ma17092149 - 4 May 2024
Viewed by 387
Abstract
Sn-3Ag-0.5Cu (SAC305)- and Sn-9Zn-based alloys (Sn-Zn-X, X = Al, In) are lead-free solders used in the fabrication of solder joints with Cu metallization. Electroplating is a facile technology used to fabricate Cu metallization. However, the addition of functional additive molecules in the plating [...] Read more.
Sn-3Ag-0.5Cu (SAC305)- and Sn-9Zn-based alloys (Sn-Zn-X, X = Al, In) are lead-free solders used in the fabrication of solder joints with Cu metallization. Electroplating is a facile technology used to fabricate Cu metallization. However, the addition of functional additive molecules in the plating solution may result in impurity residues in the Cu electroplated layer, causing damage to the solder joints. This study investigates the impurity effect on solder joints constructed by joining various solder alloys to the Cu electroplated layers. Functional additives are formulated to fabricate high-impurity and low-impurity Cu electroplated samples. The as-joined solder joint samples are thermally aged at 120 °C and 170 °C to explore the interfacial reactions between solder alloys and Cu. The results show that the impurity effect on the interfacial reactions between SAC305 and Cu is significant. Voids are massively formed at the SAC305/Cu interface incorporated with a high impurity content, and the Cu6Sn5 intermetallic compound (IMC) grows at a faster rate. In contrast, the growth of the Cu5Zn8 IMC formed in the SnZn-based solder joints is not significantly influenced by the impurity content in the Cu electroplated layers. Voids are not observed in the SnZn-based solder joints regardless of the impurity content, indicative of an insignificant impurity effect. The discrepancy of the impurity effect is rationalized by the differences in the IMC formation and associated atomic interdiffusion in the SAC305- and SnZn-based solder joints. Full article
(This article belongs to the Section Electronic Materials)
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16 pages, 8371 KiB  
Article
Influence of Severe Plastic Deformation and Aging on Low Cycle Fatigue Behavior of Al-Mg-Si Alloys
by Wonhoe Kim, Kibeom Kim and Kwonhoo Kim
Materials 2024, 17(9), 2148; https://doi.org/10.3390/ma17092148 - 3 May 2024
Viewed by 522
Abstract
Strain-controlled low cycle fatigue (LCF) tests were conducted on conventionally grained (CG) and ultrafine-grained (UFG) Al-Mg-Si alloys treated under various aging conditions. In the cyclic stress response (CSR) curves, CG peak-aged (PA) alloys showed initial cyclic hardening and subsequent saturation, whereas CG over-aged [...] Read more.
Strain-controlled low cycle fatigue (LCF) tests were conducted on conventionally grained (CG) and ultrafine-grained (UFG) Al-Mg-Si alloys treated under various aging conditions. In the cyclic stress response (CSR) curves, CG peak-aged (PA) alloys showed initial cyclic hardening and subsequent saturation, whereas CG over-aged (OA) alloys displayed cyclic softening behavior close to saturation. The UFG materials exhibited continuous cyclic softening except for UFG 3; it originates from the microstructural stability of the UFG materials processed by severe plastic deformation (SPD). Using a strain-based criterion, the LCF behavior and life of the CG and UFG materials were analyzed and evaluated; the results are discussed in terms of strengthening mechanisms and microstructural evolution. In the CG materials, the LCF life changed markedly owing to differences in deformation inhomogeneity depending on the precipitate state. However, the UFG materials displayed a decreasing LCF life as cyclic softening induced by dynamic recovery became more severe; additionally, a relationship between the microstructural stability of the UFG materials and the cyclic strain hardening exponent n′ was suggested. Full article
(This article belongs to the Special Issue Advances in Materials Processing (3rd Edition))
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14 pages, 3379 KiB  
Article
Combinatorial Quantification of Multi-Features of Coda Waves in Temperature-Affected Concrete Beams
by Gang Zheng, Linzheng Song, Wenqi Xue, Zhiyu Zhang and Benniu Zhang
Materials 2024, 17(9), 2147; https://doi.org/10.3390/ma17092147 - 3 May 2024
Viewed by 475
Abstract
Coda waves are highly sensitive to changes in medium properties and can serve as a tool for structural health monitoring (SHM). However, high sensitivity also makes them susceptible to noise, leading to excessive dispersion of monitoring results. In this paper, a coda wave [...] Read more.
Coda waves are highly sensitive to changes in medium properties and can serve as a tool for structural health monitoring (SHM). However, high sensitivity also makes them susceptible to noise, leading to excessive dispersion of monitoring results. In this paper, a coda wave multi-feature extraction method is proposed, in which three parameters, the time shift, the time stretch, and the amplitude variation of the wave trains within the time window, are totally derived. These three parameters are each mapped to the temperature variations of concrete beams, and then combined together with their optimal weight coefficients to give a best-fitted temperature–multi-parameter relationship that has the smallest errors. Coda wave signals were collected from an ultrasonic experiment on concrete beams within an environmental temperature range of 14 °C~21 °C to verify the effectiveness of the proposed method. The results indicate that the combination of multi-features derived from coda wave signals to quantify the medium temperature is feasible. Compared to the relationship established by a single parameter, the goodness-of-fit is improved. During identification, the method effectively reduces the dispersion of identification errors and mitigates the impact of noise interference on structural state assessment. Both the identification accuracy and stability are improved by more than 50%, and the order of magnitude of the identification accuracy is improved from 1 °C to 0.1 °C. Full article
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13 pages, 2904 KiB  
Article
The Effect of Water during the Compaction Process on Surface Characteristics of HMA Pavement
by Bingquan Dai, Lei Mao, Pan Pan, Xiaodi Hu and Ning Wang
Materials 2024, 17(9), 2146; https://doi.org/10.3390/ma17092146 - 3 May 2024
Viewed by 385
Abstract
During the compaction process of HMA pavement, it is common to spray cold water on the wheel of a road roller to prevent the mixture from sticking to the wheel, which might deteriorate the bonding strength between the asphalt binder and aggregate, and [...] Read more.
During the compaction process of HMA pavement, it is common to spray cold water on the wheel of a road roller to prevent the mixture from sticking to the wheel, which might deteriorate the bonding strength between the asphalt binder and aggregate, and consequently lead to surface polishing of the pavement. This paper aims to demonstrate whether the water used during the compaction process affects the surface performance of HMA pavement. In this study, the black pixel ratio and mass loss ratio were used to evaluate the water effect on the surface performance of asphalt pavement, considering the water consumption, molding temperature and long-term ageing process. The test results indicated that the water used during the compaction process would increase the risk of surface polishing of HMA pavement. This adverse effect became more significant if the HMA samples were prepared using greater water consumption, a greater molding temperature and a long-term ageing process. Moreover, there exists a certain correlation between the black pixel ratio and mass loss ratio, and their relationships were demonstrated by the experimental results in this study. It is recommended that further research concentrates on the influencing mechanism and the treatment strategy for the adverse effect caused by the water used during the compaction process. The use of more types of asphalt binders, aggregate and methodologies is also recommended in further studies. Full article
(This article belongs to the Section Construction and Building Materials)
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13 pages, 2281 KiB  
Article
Poly(ethylene oxide)- and Polyzwitterion-Based Thermoplastic Elastomers for Solid Electrolytes
by Ding-Li Xia, Shi-Peng Ding, Ze Ye, Chen Yang and Jun-Ting Xu
Materials 2024, 17(9), 2145; https://doi.org/10.3390/ma17092145 - 3 May 2024
Viewed by 465
Abstract
In this article, ABA triblock copolymer (tri-BCP) thermoplastic elastomers with poly(ethylene oxide) (PEO) middle block and polyzwitterionic poly(4-vinylpyridine) propane-1-sulfonate (PVPS) outer blocks were synthesized. The PVPS-b-PEO-b-PVPS tri-BCPs were doped with lithium bis-(trifluoromethane-sulfonyl) imide (LiTFSI) and used as solid polyelectrolytes [...] Read more.
In this article, ABA triblock copolymer (tri-BCP) thermoplastic elastomers with poly(ethylene oxide) (PEO) middle block and polyzwitterionic poly(4-vinylpyridine) propane-1-sulfonate (PVPS) outer blocks were synthesized. The PVPS-b-PEO-b-PVPS tri-BCPs were doped with lithium bis-(trifluoromethane-sulfonyl) imide (LiTFSI) and used as solid polyelectrolytes (SPEs). The thermal properties and microphase separation behavior of the tri-BCP/LiTFSI hybrids were studied. Small-angle X-ray scattering (SAXS) results revealed that all tri-BCPs formed asymmetric lamellar structures in the range of PVPS volume fractions from 12.9% to 26.1%. The microphase separation strength was enhanced with increasing the PVPS fraction (fPVPS) but was weakened as the doping ratio increased, which affected the thermal properties of the hybrids, such as melting temperature and glass transition temperature, to some extent. As compared with the PEO/LiTFSI hybrids, the PVPS-b-PEO-b-PVPS/LiTFSI hybrids could achieve both higher modulus and higher ionic conductivity, which were attributed to the physical crosslinking and the assistance in dissociation of Li+ ions by the PVPS blocks, respectively. On the basis of excellent electrical and mechanical performances, the PVPS-b-PEO-b-PVPS/LiTFSI hybrids can potentially be used as solid electrolytes in lithium-ion batteries. Full article
(This article belongs to the Special Issue Advanced Rubber Composites III)
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12 pages, 5210 KiB  
Article
Manufacturing Shape-Controllable Flexible PEDOT/rGO Composite Electrodes for Planar Micro-Supercapacitors
by Haiwei Hu, Yanyan Guo and Jiang Zhao
Materials 2024, 17(9), 2144; https://doi.org/10.3390/ma17092144 - 3 May 2024
Viewed by 562
Abstract
Flexible electronic products, with their characteristics of flexibility and wearability, have attracted significant attention and have become an important direction in the research and development of the electronics industry. Planar micro-supercapacitors (MSCs) with flexible composite electrodes can provide reliable energy support for these [...] Read more.
Flexible electronic products, with their characteristics of flexibility and wearability, have attracted significant attention and have become an important direction in the research and development of the electronics industry. Planar micro-supercapacitors (MSCs) with flexible composite electrodes can provide reliable energy support for these products, propelling their further development. The research employed a quick, effective, and environmentally friendly method of laser scribing to create shape-controllable flexible composite electrodes on composite films of Poly(3,4-ethylenedioxythiophene) and graphene oxide (PEDOT/GO), which were subsequently assembled into MSCs. An analysis of the composite electrode morphology, structure, and elemental distribution was conducted through the utilization of SEM, TEM, and XPS techniques. Following this, a comprehensive evaluation of the electrochemical performance of the flexible MSCs was carried out, which included cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and assessment of cyclic stability. The analysis of the CV results indicated that the MSCs achieved the areal capacitance of 5.78 mF/cm2 at 5 mV/s. After 5000 cycles at a current density of 0.05 mA/cm2, the capacitance retention rate was 85.4%. The high areal capacitance and strong cycle stability of MSCs highlight the potential of PEDOT/reduced graphene oxide (PEDOT/rGO) electrodes in electrode applications. Full article
(This article belongs to the Topic Electrochemical Energy Storage Materials)
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19 pages, 12445 KiB  
Article
Study on Characteristics of Ultrasound-Assisted Fracture Splitting for AISI 1045 Quenched and Tempered Steel
by Yinfang Jiang, Yangyang Wang, Xiancheng Liu, Deli Sha and Mengcheng Zhu
Materials 2024, 17(9), 2143; https://doi.org/10.3390/ma17092143 - 3 May 2024
Viewed by 394
Abstract
Ultrasonic vibration-assisted con-rod fracture splitting (UV-CFS) was used to carry out the fracture experiment of 1045 quenched and tempered steel. The effect of ultrasonic vibration on the fracture properties was studied, the fracture microstructure and the evolution of dislocations near the fracture were [...] Read more.
Ultrasonic vibration-assisted con-rod fracture splitting (UV-CFS) was used to carry out the fracture experiment of 1045 quenched and tempered steel. The effect of ultrasonic vibration on the fracture properties was studied, the fracture microstructure and the evolution of dislocations near the fracture were analyzed and the microscopic mechanism was analyzed. The results show that in the case of conventional fracture splitting without amplitude, the dimple and the fracture belong to ductile fracture. With the increase in ultrasonic amplitude, the plasticity and pore deformation of the con-rod samples decrease at first and then increase; when the amplitude reaches a certain point, the load required for cracking is reduced to a minimum and the ultrasonic hardening effect is dominant, resulting in a decrease in the plasticity of the sample, a cleavage fracture, a brittle fracture, the minimum pore deformation and high cracking quality. The research results also show that with the increase in ultrasonic amplitude, the fracture dislocation density decreases at first, then increases, and dislocation entanglement and grain breakage appear, then decrease, and multiple dislocation slip trajectories appear. The changes in the dislocation density and microstructure are consistent with the above results. Full article
(This article belongs to the Special Issue Cutting Processes for Materials in Manufacturing)
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18 pages, 4753 KiB  
Review
Advances in Catalysts for Urea Electrosynthesis Utilizing CO2 and Nitrogenous Materials: A Mechanistic Perspective
by Mengfei Zhang, Tianjian Feng, Xuanming Che, Yuhan Wang, Pengxian Wang, Mao Chai and Menglei Yuan
Materials 2024, 17(9), 2142; https://doi.org/10.3390/ma17092142 - 3 May 2024
Viewed by 485
Abstract
Electrocatalytic urea synthesis from CO2 and nitrogenous substances represents an essential advance for the chemical industry, enabling the efficient utilization of resources and promoting sustainable development. However, the development of electrocatalytic urea synthesis has been severely limited by weak chemisorption, poor activation [...] Read more.
Electrocatalytic urea synthesis from CO2 and nitrogenous substances represents an essential advance for the chemical industry, enabling the efficient utilization of resources and promoting sustainable development. However, the development of electrocatalytic urea synthesis has been severely limited by weak chemisorption, poor activation and difficulties in C–N coupling reactions. In this review, catalysts and corresponding reaction mechanisms in the emerging fields of bimetallic catalysts, MXenes, frustrated Lewis acid–base pairs and heterostructures are summarized in terms of the two central mechanisms of molecule–catalyst interactions as well as chemical bond cleavage and directional coupling, which provide new perspectives for improving the efficiency of electrocatalytic synthesis of urea. This review provides valuable insights to elucidate potential electrocatalytic mechanisms. Full article
(This article belongs to the Section Green Materials)
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21 pages, 60426 KiB  
Article
Low-Cycle Fatigue Behavior and the Combined Cyclic Hardening Material Model of Plate-Shaped Zn-22Al Alloy for Seismic Dampers
by Zongcheng Liu, Jianping Han and Penghui Yang
Materials 2024, 17(9), 2141; https://doi.org/10.3390/ma17092141 - 3 May 2024
Viewed by 422
Abstract
This study investigates the potential of the plate-shaped Zn-22 wt.% Al (Zn-22Al) alloy as an innovative energy dissipation material for seismic damping devices, since plate-shaped material is more suitable to fabricate large-scale devices for building structures. The research begins with the synthesis of [...] Read more.
This study investigates the potential of the plate-shaped Zn-22 wt.% Al (Zn-22Al) alloy as an innovative energy dissipation material for seismic damping devices, since plate-shaped material is more suitable to fabricate large-scale devices for building structures. The research begins with the synthesis of Zn-22Al alloy, given its unavailability in the commercial market. Monotonic tensile tests and low-cycle fatigue tests are performed to analyze material properties and fatigue performance of plate-shaped specimens. Monotonic tensile curves and cyclic stress–strain curves, along with SEM micrographs for microstructure and fracture surface analysis, are acquired. The combined cyclic hardening material model is calibrated to facilitate finite element analysis. Experimental results reveal exceptional ductility in Zn-22Al alloy, achieving a fracture strain of 200.37% (1.11 fracture strain). Fatigue life ranges from 1126 to 189 cycles with increasing strain amplitude (±0.8% to ±2.5%), surpassing mild steel by at least 6 times. The cyclic strain–life relationships align well with the Basquin–Coffin–Manson relationship. The combined kinematic/isotropic hardening model in ABAQUS accurately predicts the hysteretic behavior of the material, showcasing the promising potential of Zn-22Al alloy for seismic damping applications. Full article
(This article belongs to the Section Metals and Alloys)
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