Materials

16 pages, 8371 KiB

Open AccessArticle

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 - 03 May 2024

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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 lifespan 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, 4035 KiB

Open AccessArticle

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 - 03 May 2024

Viewed by 99

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 variation 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

(This article belongs to the Special Issue Research on Non-destructive Testing in Civil Engineering Materials (Second Volume))

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13 pages, 2904 KiB

Open AccessArticle

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 - 03 May 2024

Viewed by 97

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

Open AccessArticle

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 - 03 May 2024

Viewed by 124

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 (f_PVPS) 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

Open AccessArticle

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 - 03 May 2024

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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

Open AccessArticle

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 - 03 May 2024

Viewed by 118

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

Open AccessReview

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 - 03 May 2024

Viewed by 152

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

Open AccessArticle

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 - 03 May 2024

Viewed by 150

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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13 pages, 2631 KiB

Open AccessArticle

Weldability and Mechanical Properties of Pure Copper Foils Welded by Blue Diode Laser

by Tim Pasang, Shumpei Fujio, Pai-Chen Lin, Yuan Tao, Mao Sudo, Travis Kuendig, Yuji Sato and Masahiro Tsukamoto

Materials 2024, 17(9), 2140; https://doi.org/10.3390/ma17092140 - 02 May 2024

Viewed by 257

Abstract

The need to manufacture components out of copper is significantly increasing, particularly in the solar technology, semiconductor, and electric vehicle sectors. In the past few decades, infrared laser (IR) and green laser (GL) have been the primary technologies used to address this demand, [...] Read more.

The need to manufacture components out of copper is significantly increasing, particularly in the solar technology, semiconductor, and electric vehicle sectors. In the past few decades, infrared laser (IR) and green laser (GL) have been the primary technologies used to address this demand, especially for small or thin components. However, with the increased demand for energy saving, alternative joint techniques such as blue diode laser (BDL) are being actively explored. In this paper, bead-on-plate welding experiments on 0.2 mm thick pure copper samples employing a BDL are presented. Two sets of parameters were carefully selected in this investigation, namely Cu-1: Power (P) = 200 W; Speed (s) = 1 mm/s; and angle = 0°, and Cu-2: P = 200 W; s = 5 mm/s; and angle = 10°. The results from both sets of parameters produced defect-free full penetration welds. Hardness test results indicated relatively softer weld zones compared with the base metal. Tensile test samples fractured in the weld zones. Overall, the samples welded with Cu-1 parameters showed better mechanical properties, such as strength and elongation, than those welded with the Cu-2 parameters. The tensile strength and elongation obtained from Cu-1 were marginally lower than those of the unwelded pure copper. The outcomes from this research provide an alternative welding technique that is able to produce reliable, strong, and precise joints, particularly for small and thin components, which can be very challenging to produce. Full article

(This article belongs to the Special Issue Welding, Joining, and Additive Manufacturing of Metals and Alloys)

17 pages, 2688 KiB

Open AccessReview

Approaches for Enhancing Wastewater Treatment of Photocatalytic Fuel Cells: A Review

by Penghui Li, Xiaohan Zhou, Haoyi Yang, Yun He, Yujiao Kan, Yang Zhang, Yanan Shang, Yizhen Zhang, Xiaoqiang Cao and Michael K. H. Leung

Materials 2024, 17(9), 2139; https://doi.org/10.3390/ma17092139 - 02 May 2024

Viewed by 294

Abstract

Environmental pollution and energy crises have garnered global attention. The substantial discharge of organic waste into water bodies has led to profound environmental contamination. Photocatalytic fuel cells (PFCs) enabling the simultaneous removal of refractory contaminants and recovery of the chemical energy contained in [...] Read more.

Environmental pollution and energy crises have garnered global attention. The substantial discharge of organic waste into water bodies has led to profound environmental contamination. Photocatalytic fuel cells (PFCs) enabling the simultaneous removal of refractory contaminants and recovery of the chemical energy contained in organic pollutants provides a potential strategy to solve environmental issues and the energy crisis. This review will discuss the fundamentals, working principle, and configuration development of PFCs and photocatalytic microbial fuel cells (PMFCs). We particularly focus on the strategies for improving the wastewater treatment performance of PFCs/PMFCs in terms of coupled advanced oxidation processes, the rational design of high-efficiency electrodes, and the strengthening of the mass transfer process. The significant potential of PFCs/PMFCs in various fields is further discussed in detail. This review is intended to provide some guidance for the better implementation and widespread adoption of PFC wastewater treatment technologies. Full article

(This article belongs to the Special Issue Energy Storage Materials and Devices: Design, Properties and Mechanisms)

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15 pages, 12574 KiB

Open AccessArticle

Electrochemical and Mechanical Properties of Hexagonal Titanium Dioxide Nanotubes Formed by Sonoelectrochemical Anodization

by Katarzyna Arkusz, Aleksandra Jędrzejewska, Piotr Siwak and Mieczysław Jurczyk

Materials 2024, 17(9), 2138; https://doi.org/10.3390/ma17092138 - 02 May 2024

Viewed by 200

Abstract

This study aimed to investigate the fabrication and characterization of hexagonal titanium dioxide nanotubes (hTNTs) compared to compact TiO₂ layers, focusing on their structural, electrochemical, corrosion, and mechanical properties. The fabrication process involved the sonoelectrochemical anodization of titanium foil in various electrolytes [...] Read more.

This study aimed to investigate the fabrication and characterization of hexagonal titanium dioxide nanotubes (hTNTs) compared to compact TiO₂ layers, focusing on their structural, electrochemical, corrosion, and mechanical properties. The fabrication process involved the sonoelectrochemical anodization of titanium foil in various electrolytes to obtain titanium oxide layers with different morphologies. Scanning electron microscopy revealed the formation of well-ordered hexagonal TNTs with diagonals in the range of 30–95 nm and heights in the range of 3500–4000 nm (35,000–40,000 Å). The electrochemical measurements performed in 3.5% NaCl and Ringer’s solution confirmed a more positive open-circuit potential, a lower impedance, a higher electrical conductivity, and a higher corrosion rate of hTNTs compared to the compact TiO₂. The data revealed a major drop in the impedance modulus of hTNTs, with a diagonal of 46 ± 8 nm by 97% in 3.5% NaCl and 96% in Ringer’s solution compared to the compact TiO₂. Nanoindentation tests revealed that the mechanical properties of the hTNTs were influenced by their diagonal size, with decreasing hardness and Young’s modulus observed with an increasing diagonal size of the hTNTs, accompanied by increased plastic deformation. Overall, these findings suggest that hTNTs exhibit promising structural and electrochemical properties, making them potential candidates for various applications, including biosensor platforms. Full article

(This article belongs to the Special Issue Functional Nanocomposites with Controlled Surface and Mechanical Properties)

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17 pages, 3147 KiB

Open AccessArticle

Thermodynamic Modeling of the Au-Ge-X (X = In, Sb, Si, Zn) Ternary Systems

by Yuchen Bai, Qingsong Tong, Maohua Rong, Cong Tan, Xingyu Liu, Man Li and Jiang Wang

Materials 2024, 17(9), 2137; https://doi.org/10.3390/ma17092137 - 02 May 2024

Viewed by 141

Abstract

In this study, the CALPHAD approach was employed to model the thermodynamics of the Au-Ge-X (X = In, Sb, Si, Zn) ternary systems, leveraging experimental phase equilibria data and previous assessments of related binary subsystems. The solution phases were modeled as substitutional solutions, [...] Read more.

In this study, the CALPHAD approach was employed to model the thermodynamics of the Au-Ge-X (X = In, Sb, Si, Zn) ternary systems, leveraging experimental phase equilibria data and previous assessments of related binary subsystems. The solution phases were modeled as substitutional solutions, and their excess Gibbs energies were expressed using the Redlich–Kister polynomial. Owing to the unavailability of experimental data, the solubility of the third elements in the Au-In, Au-Sb, and Au-Zn binary intermetallic compounds was excluded from consideration. Additionally, stable ternary intermetallic compounds were not reported in the literature and, thus, were not taken into account in the present thermodynamic calculations. Calculations of liquidus projections, isothermal sections, and vertical sections for these ternary systems have been performed, aligning with existing experimental findings. These thermodynamic parameters form a vital basis for creating a comprehensive thermodynamic database for Au-Ge-based alloys, which is essential for the design and development of new high-temperature Pb-free solders. Full article

(This article belongs to the Special Issue Metallic Materials: Microstructure, Phase Equilibria and Thermodynamics)

25 pages, 4500 KiB

Open AccessArticle

In Vivo Investigation of 3D-Printed Calcium Magnesium Phosphate Wedges in Partial Load Defects

by Elke Hemmerlein, Elke Vorndran, Anna-Maria Schmitt, Franziska Feichtner, Anja-Christina Waselau and Andrea Meyer-Lindenberg

Materials 2024, 17(9), 2136; https://doi.org/10.3390/ma17092136 - 02 May 2024

Viewed by 258

Abstract

Bone substitutes are ideally biocompatible, osteoconductive, degradable and defect-specific and provide mechanical stability. Magnesium phosphate cements (MPCs) offer high initial stability and faster degradation compared to the well-researched calcium phosphate cements (CPCs). Calcium magnesium phosphate cements (CMPCs) should combine the properties of both [...] Read more.

Bone substitutes are ideally biocompatible, osteoconductive, degradable and defect-specific and provide mechanical stability. Magnesium phosphate cements (MPCs) offer high initial stability and faster degradation compared to the well-researched calcium phosphate cements (CPCs). Calcium magnesium phosphate cements (CMPCs) should combine the properties of both and have so far shown promising results. The present study aimed to investigate and compare the degradation and osseointegration behavior of 3D powder-printed wedges of CMPC and MPC in vivo. The wedges were post-treated with phosphoric acid (CMPC) and diammonium hydrogen phosphate (MPC) and implanted in a partially loaded defect model in the proximal rabbit tibia. The evaluation included clinical, in vivo µ-CT and X-ray examinations, histology, energy dispersive X-ray analysis (EDX) and scanning electron microscopy (SEM) for up to 30 weeks. SEM analysis revealed a zone of unreacted material in the MPC, indicating the need to optimize the manufacturing and post-treatment process. However, all materials showed excellent biocompatibility and mechanical stability. After 24 weeks, they were almost completely degraded. The slower degradation rate of the CMPC corresponded more favorably to the bone growth rate compared to the MPC. Due to the promising results of the CMPC in this study, it should be further investigated, for example in defect models with higher load. Full article

(This article belongs to the Special Issue Bone Tissue Engineering Materials: From Preparation to Properties)

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34 pages, 6746 KiB

Open AccessArticle

Design Optimization of Printed Multi-layered Electroactive Actuators Used for Steerable Guidewire in Micro-Invasive Surgery

by Simon Toinet, Mohammed Benwadih, Helga Szambolics, Christine Revenant, David Alincant, Marine Bordet, Jean-Fabien Capsal, Nellie Della-Schiava, Minh-Quyen Le and Pierre-Jean Cottinet

Materials 2024, 17(9), 2135; https://doi.org/10.3390/ma17092135 - 02 May 2024

Viewed by 170

Abstract

To treat cardiovascular diseases (i.e., a major cause of mortality after cancers), endovascular-technique-based guidewire has been employed for intra-arterial navigation. To date, most commercially available guidewires (e.g., Terumo, Abbott, Cordis, etc.) are non-steerable, which is poorly suited to the human arterial system with [...] Read more.

To treat cardiovascular diseases (i.e., a major cause of mortality after cancers), endovascular-technique-based guidewire has been employed for intra-arterial navigation. To date, most commercially available guidewires (e.g., Terumo, Abbott, Cordis, etc.) are non-steerable, which is poorly suited to the human arterial system with numerous bifurcations and angulations. To reach a target artery, surgeons frequently opt for several tools (guidewires with different size integrated into angulated catheters) that might provoke arterial complications such as perforation or dissection. Steerable guidewires would, therefore, be of high interest to reduce surgical morbidity and mortality for patients as well as to simplify procedure for surgeons, thereby saving time and health costs. Regarding these reasons, our research involves the development of a smart steerable guidewire using electroactive polymer (EAP) capable of bending when subjected to an input voltage. The actuation performance of the developed device is assessed through the curvature behavior (i.e., the displacement and the angle of the bending) of a cantilever beam structure, consisting of single- or multi-stack EAP printed on a substrate. Compared to the single-stack architecture, the multi-stack gives rise to a significant increase in curvature, even when subjected to a moderate control voltage. As suggested by the design framework, the intrinsic physical properties (dielectric, electrical, and mechanical) of the EAP layer, together with the nature and thickness of all materials (EAP and substrate), do have strong effect on the bending response of the device. The analyses propose a comprehensive guideline to optimize the actuator performance based on an adequate selection of the relevant materials and geometric parameters. An analytical model together with a finite element model (FEM) are investigated to validate the experimental tests. Finally, the design guideline leads to an innovative structure (composed of a 10-stack active layer screen-printed on a thin substrate) capable of generating a large range of bending angle (up to 190°) under an acceptable input level of 550 V, which perfectly matches the standard of medical tools used for cardiovascular surgery. Full article

(This article belongs to the Section Polymeric Materials)

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15 pages, 3997 KiB

Open AccessArticle

Wire Bow In Situ Measurement for Monitoring the Evolution of Sawing Capability of Diamond Wire Saw during Slicing Sapphire

by Zixing Yang, Hui Huang, Xinjiang Liao, Zhiyuan Lai, Zhiteng Xu and Yanjun Zhao

Materials 2024, 17(9), 2134; https://doi.org/10.3390/ma17092134 - 02 May 2024

Viewed by 259

Abstract

Electroplated diamond wire sawing is widely used as a processing method to cut hard and brittle difficult-to-machine materials. Currently, obtaining the sawing capability of diamond wire saw through the wire bow is still difficult. In this paper, a method for calculating the sawing [...] Read more.

Electroplated diamond wire sawing is widely used as a processing method to cut hard and brittle difficult-to-machine materials. Currently, obtaining the sawing capability of diamond wire saw through the wire bow is still difficult. In this paper, a method for calculating the sawing capability of diamond wire saw in real-time based on the wire bow is proposed. The influence of the renewed length per round trip, crystal orientation of sapphire, wire speed, and feed rate on the wire sawing capability has been revealed via slicing experiments. The results indicate that renewing the diamond wire saw, and reducing the wire speed and feed rate can delay the reduction in sawing capability. Furthermore, controlling the value of renewed length per round trip can make the diamond wire saw enter a stable cutting state, in which the capability of the wire saw no longer decreases. The sawing capability of diamond wire saw cutting in the A-plane of the sapphire is smaller than that of the C-plane, and a suitable feed rate or wire speed within the range of sawing parameters studied in this study can avoid a rapid decrease in the sawing capability of the wire saw during the cutting process. The knowledge obtained in this study provides a theoretical basis for monitoring the performance of the wire saw, and guidance for the wire cutting process in semiconductor manufacturing. In the future, it may even be possible to provide real-time performance parameters of diamond wire saw for the digital twin model of wire sawing. Full article

(This article belongs to the Special Issue High-Efficiency Machining Technologies and Advanced Tools for Hard and Brittle Materials)

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21 pages, 7298 KiB

Open AccessReview

Recent Developments on the Effects of Micro- and Nano-Limestone on the Hydration Process, Products, and Kinetics of Cement

by Xin Li and Mingli Cao

Materials 2024, 17(9), 2133; https://doi.org/10.3390/ma17092133 - 01 May 2024

Viewed by 368

Abstract

Limestone is commonly used in cement concrete due to its unique nature and type. It has physical effects (nucleation effect and dilution effect) and chemical effects on the hydration process of cement. This paper reviews the effects of three representative limestone materials on [...] Read more.

Limestone is commonly used in cement concrete due to its unique nature and type. It has physical effects (nucleation effect and dilution effect) and chemical effects on the hydration process of cement. This paper reviews the effects of three representative limestone materials on the hydration process, hydration products, and hydration kinetics. In the hydration process, the reaction was delayed by limestone powder with a particle size larger than 20 μm and calcium carbonate whiskers due to their dilutive effect. On the other hand, limestone powder with a particle size smaller than 20 m and calcium carbonate nanoparticles facilitated the reaction through nucleation and chemical effects. Limestone has a similar effect on hydration products, promoting the production of C-S-H through nucleation. The mechanism of action for this nucleation effect depends on the differences in crystalline form and particle size of the three types of micro- and nano-calcium. Chemical effects impact the amount of AFt produced, with the generation of new products being the main reaction influenced by the limestone admixture. Full article

(This article belongs to the Special Issue Functional Cement-Based Composites for Civil Engineering (Volume II))

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13 pages, 1324 KiB

Open AccessArticle

Advancing in Cesium Retention: Application of Magnesium Phosphate Cement Composites

by Sana Gharsallah, Nawel Khitouni, Abdulrahman Mallah, Abdulrahman Alsawi, Abdullah H. Alluhayb, Mohamed Khitouni, Clarence Charnay and Mahmoud Chemingui

Materials 2024, 17(9), 2132; https://doi.org/10.3390/ma17092132 - 01 May 2024

Viewed by 383

Abstract

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water’s natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that [...] Read more.

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water’s natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that have varied degrees of toxicity. Radiation from Cs isotopes, which are common components of radioactive waste and are known for their long half-lives (30 years), which are longer than the natural decay processes, is a major source of contamination. Adsorption is a commonly used technique for reducing this kind of contamination, and zeolite chabazite has been chosen as the best adsorbent for cesium in this particular situation. The purpose of this research is to investigate a composite material based on magnesium phosphate cement (MPC). Magnesium oxide (MgO), potassium dihydrogen phosphate (KH₂PO₄), and properly selected retarders are used to create the MPC. The optimal conditions for this composite material are investigated through the utilization of X-ray diffraction, scanning electron microscopy, BET surface area analysis, and atomic absorption spectroscopy. The principal aim is to enable innovations in the elimination of radioactive waste-contaminated water using effective cesium removal. The most promising results were obtained by using KH₂PO₄ as an acid, and MgO as a base, and aiming for an M/P ratio of two or four. Furthermore, we chose zeolite chabazite as a crucial component. The best adsorption abilities for Cs were found at Q_ads = 106.997 mg/g for S₂ and Q_ads = 122.108 mg/g for S₁. As a result, zeolite is an eco-friendly material that is a potential usage option, with many benefits, such as low prices, stability, and ease of regeneration and use. Full article

(This article belongs to the Special Issue New Trends of Functional Materials for Wastewater Treatment Applications)

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18 pages, 2746 KiB

Open AccessArticle

Valorization of the Residual Fraction of Coal Tailings: A Mineral Circularity Strategy for the Clay Ceramic Industry in the Carboniferous Region of Santa Catarina, Southern Brazil

by Wagner Benedet Rebelo, Alexandre Zaccaron, Emily Saviatto, Eduarda Fraga Olivo, Juliana Acordi, Fabiano Raupp-Pereira and Manuel Joaquim Ribeiro

Materials 2024, 17(9), 2131; https://doi.org/10.3390/ma17092131 - 01 May 2024

Viewed by 246

Abstract

Mineral extraction of coal in the carboniferous region of southern Santa Catarina (Brazil) plays a significant role in the regional economy. However, this activity has severe environmental impacts, with approximately 65% of the extracted mineral being discarded as a rejected material (deposited in [...] Read more.

Mineral extraction of coal in the carboniferous region of southern Santa Catarina (Brazil) plays a significant role in the regional economy. However, this activity has severe environmental impacts, with approximately 65% of the extracted mineral being discarded as a rejected material (deposited in landfills). The identification of the technological potential of these materials, based on the geological aspects of the extraction site and the beneficiation operations applied to obtain coal, provides the opportunity to add value to different residual fractions that can be reused. Thus, waste valorization, the main objective of this work, has recently become a strategy for the application of these minerals in the production of clay ceramics using a systematic approach named CPQvA, which means “classification, potentiality, quantity/viability, and applicability”. The use of these materials as secondary mineral sources can avoid the deposition of these materials in industrial landfills and help to reduce the pressure on landfills, which receive an average of four million tons of material annually. In this study, the residual fraction, part of the tailing from coal beneficiation, known as coal fines, was evaluated for formulation valorization in clay ceramics. This residual fraction was classified as non-hazardous (class II-A, non-inert). X-ray fluorescence spectrometry, X-ray diffraction, and thermogravimetric analysis were performed to characterize the moisture content, particle-size distribution, and coal content to be used in the development of different formulations using the residual fraction of coal tailings (ranging from 0 to 40%) that are of technological interest to the sector. Processing parameters, such as firing at different temperatures (750, 800, 850, and 900 °C), were also correlated with these formulations. The results were compared with those of a reference ceramic formulation from the local productive arrangement of Morro da Fumaça (Arranjo Produtivo Local Cerâmica Vermelha de Morro da Fumaça). The various relationships between the materials were characterized in terms of their thermal shrinkage, water absorption, and mechanical resistance. Leaching and solubilization environmental tests revealed that both the industrial standard formulation and formulations with the application of the residual fraction were classified as non-hazardous materials. Thus, the method of using a mining residual fraction in the formulation of clay ceramics proved to be beneficial for the circular economy in the regional mineral sector through productive and environmental gains; the primary mineral resource and energy consumptions and the impacts related to waste generation were reduced. The results of this study can be applied to similar situations in other parts of the world. Full article

(This article belongs to the Special Issue Sustainability, Circular Economy and Waste Recycling: Advances in Materials Research (2nd Edition))

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14 pages, 2300 KiB

Open AccessArticle

Effect of Luting Materials on the Accuracy of Fit of Zirconia Copings: A Non-Destructive Digital Analysis Method

by Lara Berger, Ragai-Edward Matta, Christian Markus Weiß, Werner Adler, Manfred Wichmann and José Ignacio Zorzin

Materials 2024, 17(9), 2130; https://doi.org/10.3390/ma17092130 - 01 May 2024

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Abstract

The marginal accuracy of fit between prosthetic restorations and abutment teeth represents an essential aspect with regard to long-term clinical success. Since the final gap is also influenced by the luting techniques and materials applied, this study analyzed the accuracy of the fit [...] Read more.

The marginal accuracy of fit between prosthetic restorations and abutment teeth represents an essential aspect with regard to long-term clinical success. Since the final gap is also influenced by the luting techniques and materials applied, this study analyzed the accuracy of the fit of single-tooth zirconia copings before and after cementation using different luting materials. Forty plaster dies with a corresponding zirconia coping were manufactured based on a single tooth chamfer preparation. The copings were luted on the plaster dies (n = 10 per luting material) with a zinc phosphate (A), glass–ionomer (B), self-adhesive resin (C), or resin-modified glass–ionomer cement (D). The accuracy of fit for each coping was assessed using a non-destructive digital method. Intragroup statistical analysis was conducted using Wilcoxon signed rank tests and intergroup analysis by Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). Accuracy of fit was significantly different before/after cementation within A (0.033/0.110 µm) and B (0.035/0.118 µm; p = 0.002). A had a significantly increased marginal gap compared to C and D, and B compared to C and D (p ≤ 0.001). Significantly increased vertical discrepancies between A and B versus C and D (p < 0.001) were assessed. Of the materials under investigation, the zinc phosphate cement led to increased vertical marginal discrepancies, whereas the self-adhesive resin cement did not influence the restoration fit. Full article

(This article belongs to the Special Issue Advanced Dental Materials: From Design to Application)

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16 pages, 19168 KiB

Open AccessArticle

Enhanced Long-Term Corrosion Resistance of 316L Stainless Steel by Multilayer Amorphous Carbon Coatings

by Shuyu Li, Hao Li, Peng Guo, Xiaowei Li, Wei Yang, Guanshui Ma, Kazuhito Nishimura, Peiling Ke and Aiying Wang

Materials 2024, 17(9), 2129; https://doi.org/10.3390/ma17092129 - 01 May 2024

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Abstract

Diamond-like carbon (DLC) coatings are effective in protecting the key components of marine equipment and can greatly improve their short-term performance (1.5~4.5 h). However, the lack of investigation into their long-term (more than 200 h) performance cannot meet the service life requirements of [...] Read more.

Diamond-like carbon (DLC) coatings are effective in protecting the key components of marine equipment and can greatly improve their short-term performance (1.5~4.5 h). However, the lack of investigation into their long-term (more than 200 h) performance cannot meet the service life requirements of marine equipment. Here, three multilayered DLC coatings, namely Ti/DLC, TiC_x/DLC, and Ti-TiC_x/DLC, were prepared, and their long-term corrosion resistance was investigated. Results showed that the corrosion current density of all DLC coatings was reduced by 1–2 orders of magnitude compared with bare 316L stainless steel (316Lss). Moreover, under long-term (63 days) immersion in a 3.5 wt.% NaCl solution, all DLC coatings could provide excellent long-term corrosion protection for 316Lss, and Ti-TiC_x/DLC depicted the best corrosion resistance; the polarization resistances remained at ~3.0 × 10⁷ Ω·cm² after immersion for 63 days, with more interfaces to hinder the penetration of the corrosive media. Meanwhile, during neutral salt spray (3000 h), the corrosion resistance of Ti/DLC and TiC_x/DLC coatings showed a certain degree of improvement because the insoluble corrosion products at the defects blocked the subsequent corrosion. This study can provide a route to designing amorphous carbon protective coatings for long-term marine applications in different environments. Full article

(This article belongs to the Special Issue Friction, Corrosion and Protection of Material Surfaces)

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11 pages, 3519 KiB

Open AccessArticle

Dimensional Stability of Additively Manufactured Dentate Maxillary Diagnostic Casts in Biobased Model Resin

by Münir Demirel, Almira Ada Diken Türksayar, Sandra Petersmann, Sebastian Spintzyk and Mustafa Borga Donmez

Materials 2024, 17(9), 2128; https://doi.org/10.3390/ma17092128 - 01 May 2024

Viewed by 249

Abstract

This study aimed to evaluate the dimensional stability of maxillary diagnostic casts fabricated from a biobased model resin, which consists of 50% renewable raw materials for sustainable production, a model resin, and stone, over one month. A master maxillary stone cast was digitized [...] Read more.

This study aimed to evaluate the dimensional stability of maxillary diagnostic casts fabricated from a biobased model resin, which consists of 50% renewable raw materials for sustainable production, a model resin, and stone, over one month. A master maxillary stone cast was digitized with a laboratory scanner to generate a reference file. This master cast was also scanned with an intraoral scanner to additively manufacture casts with a biobased model resin (BAM) and a model resin (AM). Polyvinylsiloxane impressions of the master cast were also made and poured in type III stone (CV) (n = 8). The same laboratory scanner was used to digitize each model one day (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4) after fabrication. Deviations from the reference file were calculated with an analysis software and analyzed with generalized linear model analysis (α = 0.05). The interaction between the material and the time point affected measured deviations (p < 0.001). Regardless of the time point, CV had the lowest and AM had the highest deviations (p < 0.001). BAM mostly had lower deviations at T0 and mostly had higher deviations at T4 (p ≤ 0.011). AM had the highest deviations at T4 and then at T3, whereas it had the lowest deviations at T0 (p ≤ 0.002). The measured deviations of CV increased after each time point (p < 0.001). BAM casts had deviations within the previously reported clinically acceptable thresholds over one month and had acceptable dimensional stability. Therefore, tested biobased resin may be a viable alternative for the sustainable manufacturing of maxillary diagnostic casts that are to be used clinically. Full article

(This article belongs to the Special Issue Model Design and Application of Dental Materials)

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19 pages, 7292 KiB

Open AccessArticle

A Study on the Microstructure Regulation Effect of Niobium Doping on LiNi_0.88Co_0.05Mn_0.07O₂ and the Electrochemical Performance of the Composite Material under High Voltage

by Xinrui Xu, Junjie Liu, Bo Wang, Jiaqi Wang, Yunchang Wang, Weisong Meng and Feipeng Cai

Materials 2024, 17(9), 2127; https://doi.org/10.3390/ma17092127 - 30 Apr 2024

Viewed by 198

Abstract

High-nickel ternary materials are currently the most promising lithium battery cathode materials due to their development and application potential. Nevertheless, these materials encounter challenges like cation mixing, lattice oxygen loss, interfacial reactions, and microcracks. These issues are exacerbated at high voltages, compromising their [...] Read more.

High-nickel ternary materials are currently the most promising lithium battery cathode materials due to their development and application potential. Nevertheless, these materials encounter challenges like cation mixing, lattice oxygen loss, interfacial reactions, and microcracks. These issues are exacerbated at high voltages, compromising their cyclic stability and safety. In this study, we successfully prepared Nb⁵⁺-doped high-nickel ternary cathode materials via a high-temperature solid-phase method. We investigated the impact of Nb⁵⁺ doping on the microstructure and electrochemical properties of LiNi_0.88Co_0.05Mn_0.07O₂ ternary cathode materials by varying the amount of Nb₂O₅ added. The experimental results suggest that Nb⁵⁺ doping does not alter the crystal structure but modifies the particle morphology, yielding radially distributed, elongated, rod-like structures. This morphology effectively mitigates the anisotropic volume changes during cycling, thereby bolstering the material’s cyclic stability. The material exhibits a discharge capacity of 224.4 mAh g⁻¹ at 0.1C and 200.3 mAh g⁻¹ at 1C, within a voltage range of 2.7 V–4.5 V. Following 100 cycles at 1C, the capacity retention rate maintains a high level of 92.9%, highlighting the material’s remarkable capacity retention and cyclic stability under high-voltage conditions. The enhancement of cyclic stability is primarily due to the synergistic effects caused by Nb⁵⁺ doping. Nb⁵⁺ modifies the particle morphology, thereby mitigating the formation of microcracks. The formation of high-energy Nb-O bonds prevents oxygen precipitation at high voltages, minimizes the irreversibility of the H2–H3 phase transition, and thereby enhances the stability of the composite material at high voltages. Full article

(This article belongs to the Topic Advanced Nanomaterials for Lithium-Ion Batteries)

20 pages, 2811 KiB

Open AccessArticle

Multi-Objective Optimization of a Multi-Cavity, Significant Wall Thickness Difference Extrusion Profile Mold Design for New Energy Vehicles

by Xuda Xu, Feng Jiang, Jianxiang Li, Hongfeng Huang and Chunli Jiang

Materials 2024, 17(9), 2126; https://doi.org/10.3390/ma17092126 - 30 Apr 2024

Viewed by 207

Abstract

With the rapid development of the new energy vehicle market, the demand for extruded profiles for battery trays, mainly characterized by significant wall thickness differences in multiple chambers, is increasing, posing new challenges to production and quality control. This study examines the multi-objective [...] Read more.

With the rapid development of the new energy vehicle market, the demand for extruded profiles for battery trays, mainly characterized by significant wall thickness differences in multiple chambers, is increasing, posing new challenges to production and quality control. This study examines the multi-objective optimization problem in the design process of aluminum profile dies with multi-cavity profiles and significant wall thickness differences. Using QFORM-extrusion professional aluminum extrusion finite element analysis software and the response surface analysis method, the standard deviation of the velocity (SDV), standard deviation of the pressure (SDP), and thick wall hydrostatic pressure (TWHP) on the profile section at the die exit are optimized. By analyzing the functional relationship between the key die structure parameters (the height of the baffle plates, the length of the bearing, and the height of the false mandrel) and the optimization objective, the optimal combination scheme of die structure parameters was obtained using the NSGA2 (non-dominated sorting genetic algorithm-2) multi-objective genetic optimization algorithm. The results show that, compared with the initial design scheme, the standard deviation of profile section velocity was reduced by 5.33%, the standard deviation of pressure was reduced by 11.16%, and the thick wall hydrostatic pressure was increased by 26.47%. The die designed and manufactured using this scheme successfully completed the hot extrusion production task, and the profile quality met the predetermined requirements, thus verifying the effectiveness of this study in optimizing the design of a multi-cavity aluminum profile die with significant differences in wall thickness for complex structures. Full article

(This article belongs to the Section Materials Simulation and Design)

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17 pages, 1484 KiB

Open AccessArticle

Failure Mechanism and Thermal Runaway in Batteries during Micro-Overcharge Aging at Different Temperatures

by Zhizu Zhang, Changwei Ji and Yanan Wang

Materials 2024, 17(9), 2125; https://doi.org/10.3390/ma17092125 - 30 Apr 2024

Viewed by 170

Abstract

This paper provides insights into the four key behaviors and mechanisms of the aging to failure of batteries in micro-overcharge cycles at different temperatures, as well as the changes in thermal stability. The test results from a scanning electron microscope (SEM) and an [...] Read more.

This paper provides insights into the four key behaviors and mechanisms of the aging to failure of batteries in micro-overcharge cycles at different temperatures, as well as the changes in thermal stability. The test results from a scanning electron microscope (SEM) and an energy-dispersive spectrometer (EDS) indicate that battery failure is primarily associated with the rupture of cathode materials, the fracturing and pulverization of electrode materials on the anode current collector, and the formation of lithium dendrites. Additionally, battery safety is influenced by environmental temperatures and the battery’s state of health (SOH), with failed batteries exhibiting the poorest stability and the highest mass loss rates. Under isothermal conditions, micro-overcharge leads to battery failure without thermal runaway. Thus, temperature stands out as the most influential factor in battery safety. These insights hold significant theoretical and practical value for the development of more precise and secure battery management systems. Full article

(This article belongs to the Section Energy Materials)

33 pages, 16215 KiB

Open AccessReview

High-Performance Nanoscale Metallic Multilayer Composites: Techniques, Mechanical Properties and Applications

by Mahmoud Ebrahimi, Bangcai Luo, Qudong Wang and Shokouh Attarilar

Materials 2024, 17(9), 2124; https://doi.org/10.3390/ma17092124 - 30 Apr 2024

Viewed by 271

Abstract

Due to their exceptional properties and diverse applications, including to magnetic devices, thermoelectric materials, catalysis, biomedicine, and energy storage, nanoscale metallic multilayer composites (NMMCs) have recently attracted great attention. The alternating layers of two or more metals that make up NMMCs are each [...] Read more.

Due to their exceptional properties and diverse applications, including to magnetic devices, thermoelectric materials, catalysis, biomedicine, and energy storage, nanoscale metallic multilayer composites (NMMCs) have recently attracted great attention. The alternating layers of two or more metals that make up NMMCs are each just a few nanometers thick. The difficulties in producing and synthesizing new materials can be overcome by using nanoscale multilayer architectures. By adjusting the layer thickness, composition, and interface structure, the mechanical properties of these materials can be controlled. In addition, NMMCs exhibit unusually high strength at thin layer thicknesses because the multilayers have exceptionally high strength, as the individual layer thicknesses are reduced to the nanoscale. The properties of NMMCs depend on the individual layers. This means that the properties can be tuned by varying the layer thickness, composition, and interface structure. Therefore, this review article aims to provide a comprehensive overview of the mechanical properties and the application of high-performance NMMCs. The paper briefly discusses the fabrication methods used to produce these composites and highlights their potential in various fields, such as electronics, energy storage, aerospace, and biomedical engineering. Furthermore, the electrical conductivity, mechanical properties, and thermal stability of the above composite materials are analyzed in detail. The review concludes with a discussion of the future prospects and challenges associated with the development of NMMCs. Full article

(This article belongs to the Special Issue Nanocomposite Based Materials for Various Applications)

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31 pages, 4201 KiB

Open AccessReview

Phytochemicals from Bark Extracts and Their Applicability in the Synthesis of Thermosetting Polymers: An Overview

by Tomasz Szmechtyk and Magdalena Małecka

Materials 2024, 17(9), 2123; https://doi.org/10.3390/ma17092123 - 30 Apr 2024

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Abstract

This review focuses on recent research on the phytochemicals found in bark from different trees and their potential to be used as substrates for the synthesis of thermosetting resins. Recent studies about the influence of each bark harvesting step on the extracted phytochemicals, [...] Read more.

This review focuses on recent research on the phytochemicals found in bark from different trees and their potential to be used as substrates for the synthesis of thermosetting resins. Recent studies about the influence of each bark harvesting step on the extracted phytochemicals, from debarking to extraction, are investigated. A comparison of bark extracts in terms of the correlation between extraction conditions and efficiency (based on the total phenolic content (TPC) and extraction yield) is presented for six groups of trees (Norway spruce, pine species, other conifers, oak species, other deciduous trees of the north temperate zone, tropical and subtropical trees) and evaluated. The evaluation revealed that there is an interesting relationship between the extraction time and the type of solvent for some types of tree bark. It was found that a relatively short extraction time and a solvent temperature close to the boiling point are favourable. The latest research on the application of bark extracts in different types of thermosetting resins is described. This review discusses the attractiveness of bark extracts in terms of functional groups and the possibilities arising from extractable phytochemicals. In addition, different approaches (selective versus holistic) and methods of application are presented and compared. Full article

(This article belongs to the Section Polymeric Materials)

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13 pages, 722 KiB

Open AccessArticle

Fracture Resistance of 3D-Printed Occlusal Veneers Made from 3Y-TZP Zirconia

by Andreas Zenthöfer, Dennis Fien, Johannes Rossipal, Ali Ilani, Clemens Schmitt, Sebastian Hetzler, Peter Rammelsberg and Stefan Rues

Materials 2024, 17(9), 2122; https://doi.org/10.3390/ma17092122 - 30 Apr 2024

Viewed by 180

Abstract

The aim of this paper was to evaluate the fracture resistance of 3D-printed zirconia occlusal veneers (OVs) of different thicknesses and supported by different abutment materials. Materials and Methods: The standard OV of a natural molar was prepared and digitized using a laboratory [...] Read more.

The aim of this paper was to evaluate the fracture resistance of 3D-printed zirconia occlusal veneers (OVs) of different thicknesses and supported by different abutment materials. Materials and Methods: The standard OV of a natural molar was prepared and digitized using a laboratory 3D scanner. The resulting digital tooth abutment was milled either using cobalt–chromium (CoCr) or a fiber-reinforced composite (FRC). All the abutments were digitized and standardized OVs (30° tilt of all the cusps) designed with 0.4 mm, 0.6 mm, or 0.8 mm wall thicknesses. The OVs were fabricated using either the Programill PM7 milling device (Ivoclar Vivadent, PM) or one of two 3D zirconia printers, Cerafab 7500 (Lithoz, LC) or Zipro-D (AON, ZD). The ZD samples were only tested on CoCr abutments. The completed OVs were luted to their abutments and subjected to artificial aging, consisting of thermocycling and chewing simulation before fracture testing with a steel sphere (d = 8 mm) as an antagonist with three contact points on the occlusal OV surface. Besides the total fracture resistance F_u,tot, the lowest contact force F_u,cont leading to the local fracture of a cusp was of interest. The possible effects of the factors fabrication approach, wall thickness, and abutment material were evaluated using ANOVA (α = 0.05; SPSS Ver.28). Results: The total fracture resistance/contact forces leading to failure ranged from F_u,tot = 416 ± 83 N/F_u,cont = 140 ± 22 N for the 0.4 mm OVs fabricated using LC placed on the FRC abutments to F_u,tot = 3309 ± 394 N (ZD)/F_u,cont = 1206 ± 184 N (PM) for the 0.8 mm thick OVs on the CoCr abutments. All the factors (the fabrication approach, abutment material, and OV wall thickness) had an independent effect on F_u,tot as well as F_u,cont (p < 0.032). In pairwise comparisons for F_u,tot of the OVs luted to the CoCr abutments, the ZD samples statistically outperformed the LC- and PM-fabricated teeth irrespective of the thickness (p < 0.001). Conclusions: Within the limitations of this study, the printed occlusal veneers exhibited comparable fracture resistances to those of the milled variants. However, more resilient abutments (FRC as a simulation of dentine) as well as a thinner wall thickness led to reduced OV fracture resistance, suggesting that 0.4 mm thick zirconia OVs should not be unreservedly used in every clinical situation. Full article

(This article belongs to the Special Issue Ceramic Dental Restorations: From Materials Sciences to Applications)

16 pages, 10891 KiB

Open AccessArticle

Towards Understanding Formation Mechanism of Cellular Structures in Laser Powder Bed Fused AlSi10Mg

by Xiaoying Zhang, Xingpeng Zhang, Wenbo Liu, Aoke Jiang and Yu Long

Materials 2024, 17(9), 2121; https://doi.org/10.3390/ma17092121 - 30 Apr 2024

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Abstract

A new approach is proposed that identifies three different zones of the Si-rich network structure (the cellular structure) in laser powder bed fused (LPBF) AlSi10Mg alloy, based on the variation in morphology, grain growth transition, and melt pool solidification conditions. The three identified [...] Read more.

A new approach is proposed that identifies three different zones of the Si-rich network structure (the cellular structure) in laser powder bed fused (LPBF) AlSi10Mg alloy, based on the variation in morphology, grain growth transition, and melt pool solidification conditions. The three identified zones are denoted in the present work as the liquid solidification zone (LSZ), the mushy solidification zone (MSZ), and the heat affected zone (HAZ). The LSZ is the result of liquid–solid transformation, showing small planar growth at the boundary and large cellular growth in the center, while the MSZ is related to a semisolid reaction, and the HAZ arises from a short-time aging process. The boundary between the LSZ and MSZ is identified by the change of grain growth direction and the Si-rich network advancing direction. The boundary between MSZ and HAZ is identified by the start of the breakdown of the Si-rich network. In addition, it is found that the fracture is generated in and propagates along the HAZ during tensile tests. Full article

(This article belongs to the Special Issue High-Performance Additive Manufacturing and Welding of Metals and Alloys)

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5 pages, 9973 KiB

Open AccessCorrection

Correction: Fang et al. Study on Dispersion, Adsorption, and Hydration Effects of Polycarboxylate Superplasticizers with Different Side Chain Structures in Reference Cement and Belite Cement. Materials 2023, 16, 4168

by Yunhui Fang, Xiaofang Zhang, Dongming Yan, Zhijun Lin, Xiuxing Ma, Junying Lai, Yi Liu, Yuliang Ke, Zhanhua Chen and Zhaopeng Wang

Materials 2024, 17(9), 2120; https://doi.org/10.3390/ma17092120 - 30 Apr 2024

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Abstract

In the original publication [...] Full article

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29 pages, 3116 KiB

Open AccessReview

Advances in Computational Methods for Modeling Photocatalytic Reactions: A Review of Recent Developments

by Sergey Gusarov

Materials 2024, 17(9), 2119; https://doi.org/10.3390/ma17092119 - 30 Apr 2024

Viewed by 511

Abstract

Photocatalysis is a fascinating process in which a photocatalyst plays a pivotal role in driving a chemical reaction when exposed to light. Its capacity to harness light energy triggers a cascade of reactions that lead to the formation of intermediate compounds, culminating in [...] Read more.

Photocatalysis is a fascinating process in which a photocatalyst plays a pivotal role in driving a chemical reaction when exposed to light. Its capacity to harness light energy triggers a cascade of reactions that lead to the formation of intermediate compounds, culminating in the desired final product(s). The essence of this process is the interaction between the photocatalyst’s excited state and its specific interactions with reactants, resulting in the creation of intermediates. The process’s appeal is further enhanced by its cyclic nature—the photocatalyst is rejuvenated after each cycle, ensuring ongoing and sustainable catalytic action. Nevertheless, comprehending the photocatalytic process through the modeling of photoactive materials and molecular devices demands advanced computational techniques founded on effective quantum chemistry methods, multiscale modeling, and machine learning. This review analyzes contemporary theoretical methods, spanning a range of lengths and accuracy scales, and assesses the strengths and limitations of these methods. It also explores the future challenges in modeling complex nano-photocatalysts, underscoring the necessity of integrating various methods hierarchically to optimize resource distribution across different scales. Additionally, the discussion includes the role of excited state chemistry, a crucial element in understanding photocatalysis. Full article

(This article belongs to the Special Issue Advanced Photocatalytic Material: Synthesis, Characterization and Application)

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Materials, Volume 17, Issue 9 (May-1 2024) – 215 articles

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