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Keywords = amorphous magnetic materials

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25 pages, 3459 KiB  
Article
Phase Composition, Structure, and Microwave Absorption of Magnetron-Sputtered Co–C–Cr Multilayer Films
by Nadezhda Prokhorenkova, Almira Zhilkashinova, Madi Abilev, Leszek Łatka, Igor Ocheredko and Assel Zhilkashinova
Compounds 2025, 5(3), 27; https://doi.org/10.3390/compounds5030027 - 20 Jul 2025
Viewed by 239
Abstract
Multilayer thin films composed of cobalt (Co), carbon (C), and chromium (Cr) possess promising electromagnetic properties, yet the combined Co–C–Cr system remains underexplored, particularly regarding its performance as a microwave absorber. Existing research has primarily focused on binary Co–C or Co–Cr compositions, leaving [...] Read more.
Multilayer thin films composed of cobalt (Co), carbon (C), and chromium (Cr) possess promising electromagnetic properties, yet the combined Co–C–Cr system remains underexplored, particularly regarding its performance as a microwave absorber. Existing research has primarily focused on binary Co–C or Co–Cr compositions, leaving a critical knowledge gap in understanding how ternary multilayer architectures influence electromagnetic behavior. This study addresses this gap by investigating the structure, phase composition, and microwave absorption performance of Co–C–Cr multilayer coatings fabricated via magnetron sputtering onto porous silicon substrates. This study compares four-layer and eight-layer configurations to assess how multilayer architecture affects impedance matching, reflection coefficients, and absorption characteristics within the 8.2–12.4 GHz frequency range. Structural analyses using X-ray diffraction and transmission electron microscopy confirm the coexistence of amorphous and nanocrystalline phases, which enhance absorption through dielectric and magnetic loss mechanisms. Both experimental and simulated results show that increasing the number of layers improves impedance gradients and broadens the operational bandwidth. The eight-layer coatings demonstrate a more uniform absorption response, while four-layer structures exhibit sharper resonant minima. These findings advance the understanding of ternary multilayer systems and contribute to the development of frequency-selective surfaces and broadband microwave shielding materials. Full article
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18 pages, 6380 KiB  
Article
Synthesis and Application of Fe3O4–ZrO2 Magnetic Nanoparticles for Fluoride Adsorption from Water
by Israel Águila-Martínez, José Antonio Pérez-Tavares, Efrén González-Aguiñaga, Pablo Eduardo Cardoso-Avila, Héctor Pérez Ladrón de Guevara and Rita Patakfalvi
Inorganics 2025, 13(7), 248; https://doi.org/10.3390/inorganics13070248 - 19 Jul 2025
Viewed by 616
Abstract
This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe3O4–ZrO2) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios [...] Read more.
This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe3O4–ZrO2) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios of 1:1, 1:2, and 1:4, and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). FTIR analysis confirmed the presence of Fe3O4 and ZrO2 functional groups, while XRD showed that increased Zr content led to a dominant amorphous phase. SEM and EDS analyses revealed quasi-spherical and elongated morphologies with uniform elemental distribution, maintaining the designed Fe/Zr ratios. Preliminary adsorption tests identified the Fe/Zr = 1:1 (M1) nanoadsorbent as the most effective due to its high surface homogeneity and optimal fluoride-binding characteristics. Adsorption experiments demonstrated that the material achieved a maximum fluoride adsorption capacity of 70.4 mg/g at pH 3, with the adsorption process best fitting the Temkin isotherm model (R2 = 0.987), suggesting strong adsorbate–adsorbent interactions. pH-dependent studies confirmed that adsorption efficiency decreased at higher pH values due to electrostatic repulsion and competition with hydroxyl ions. Competitive ion experiments revealed that common anions such as nitrate, chloride, and sulfate had negligible effects on fluoride adsorption, whereas bicarbonate, carbonate, and phosphate reduced removal efficiency due to their strong interactions with active adsorption sites. The Fe3O4–ZrO2 nanoadsorbent exhibited excellent magnetic properties, facilitating rapid and efficient separation using an external magnetic field, making it a promising candidate for practical water treatment applications. Full article
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13 pages, 6320 KiB  
Article
Enhanced Microwave Absorption Performance of Amorphous Co100−xFex Nanoparticles
by Zhen Wang, Chao An, Fenglong Wang, Hongsheng Liang, Zhaoyang Hou, Hao Shen and Hongjing Wu
Nanomaterials 2025, 15(14), 1091; https://doi.org/10.3390/nano15141091 - 14 Jul 2025
Viewed by 268
Abstract
Metallic magnetic materials are extensively used to mitigate electromagnetic interference due to their high Curie temperatures and permeability. However, their high permittivity often hinders impedance-matching effectiveness, limiting their utility. In this study, amorphous cobalt–iron (Co100−xFex) alloy nanoparticles with relatively [...] Read more.
Metallic magnetic materials are extensively used to mitigate electromagnetic interference due to their high Curie temperatures and permeability. However, their high permittivity often hinders impedance-matching effectiveness, limiting their utility. In this study, amorphous cobalt–iron (Co100−xFex) alloy nanoparticles with relatively low permittivity were synthesized using a simple aqueous reduction method at room temperature. The effect of atomic ratio variation on the microwave absorption properties of these nanoparticles was investigated across 2–18 GHz. The amorphous Co100−xFex nanoparticles exhibited excellent electromagnetic wave absorption performance, achieving an effective absorption bandwidth of 5.6 GHz, a matching thickness of 2.60 mm, and a reflection loss of −42 dB. Full article
(This article belongs to the Special Issue Harvesting Electromagnetic Fields with Nanomaterials)
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16 pages, 4371 KiB  
Article
Graphitization Optimization of Cobalt-Doped Porous Carbon Derived from Seaweed Sludge for Enhanced Microwave Absorption
by Kai Liu, Yusen Ai, Mei Cui, Renliang Huang and Rongxin Su
Polymers 2025, 17(11), 1572; https://doi.org/10.3390/polym17111572 - 5 Jun 2025
Cited by 1 | Viewed by 398
Abstract
Utilizing biomass resources to develop carbon-based microwave-absorbing materials adheres to the principles of sustainable development. Nevertheless, the single loss mechanism of pure carbon materials is limited. Additionally, the carbonization of artificially synthesized polymers has poor environmental performance and involves complex processes. These issues [...] Read more.
Utilizing biomass resources to develop carbon-based microwave-absorbing materials adheres to the principles of sustainable development. Nevertheless, the single loss mechanism of pure carbon materials is limited. Additionally, the carbonization of artificially synthesized polymers has poor environmental performance and involves complex processes. These issues restrict their performance and broader applicability. In this study, cobalt-doped seaweed sludge porous carbon (Co/SSPC) with different cobalt contents was synthesized via a simple grinding–carbonization treatment. The addition of cobalt can regulate the graphitization degree of porous carbon, achieving a suitable amorphous-to-crystalline carbon ratio of 2.05. This not only enhances magnetic loss but also modifies dielectric loss and optimizes impedance matching. The construction of synergistic magnetic and dielectric loss mechanisms enables Co/SSPC to exhibit excellent microwave absorption performance. Specifically, Co/SSPC achieved a minimum reflection loss (RLmin) of −66.91 dB at a thickness of 4.79 mm and an effective absorption bandwidth (EAB) of 5.09 GHz at a thickness of 1.6 mm. This study provides a practical approach for the functional application of natural polymer waste algal sludge and highlights its potential in the low-cost production of microwave absorbing materials. Full article
(This article belongs to the Section Polymer Applications)
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14 pages, 4930 KiB  
Article
Magnetic Characteristics of FeSiB Cores in Motors Revealed by Experiment and Finite-Element Simulation
by Meng Wang, Long Hou, Wenwei Ju, Yan Ma, Zhongkai Guo, Dianguo Ma, Lanju Liang, Haishun Liu and Weiming Yang
Materials 2025, 18(10), 2325; https://doi.org/10.3390/ma18102325 - 16 May 2025
Viewed by 428
Abstract
Iron core loss (Pcm) is the main source of energy dissipation in motors, primarily affected by the stator material, which necessitates the optimization of soft-magnetic materials. In this work, the magnetic characteristics of FeSiB amorphous alloys and their influence on [...] Read more.
Iron core loss (Pcm) is the main source of energy dissipation in motors, primarily affected by the stator material, which necessitates the optimization of soft-magnetic materials. In this work, the magnetic characteristics of FeSiB amorphous alloys and their influence on motors were systematically investigated via both experiment and finite-element simulation. It was found that the Pcm of the FeSiB core initially decreased significantly during heating but subsequently increased with a further temperature rise. In particular, after annealing at 460 °C for 10 min, the FeSiB core exhibited the lowest Pcm of 0.11 W/kg (50 Hz, 1 T) and 5.45 W/kg (1 kHz, 1 T), which correlated well with the changes in the magnetization. With the help of the finite-element analysis, the low Pcm of the motor using the FeSiB core was further demonstrated, and was closely associated with the dominance of the stator loss. Additionally, the magnetic flux density cloud and the related electromagnetic torque of the motor were comparatively analyzed to unveil the potential advantages of the current FeSiB core. This work provides an important theoretical basis for the design and development of amorphous/nanocrystalline motors. Full article
(This article belongs to the Section Materials Simulation and Design)
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13 pages, 1720 KiB  
Article
Evaluation of Mechanical Stability, and Magnetic and Acoustic Properties of a Transformer Core Made of Amorphous Steel Consolidated with a Silane-Based Hybrid Binder
by Jolanta Nieroda, Grzegorz Kmita, Michal Kozupa, Szymon Piela, Maciej Sitarz and Andrzej Rybak
Appl. Sci. 2025, 15(9), 5141; https://doi.org/10.3390/app15095141 - 6 May 2025
Viewed by 446
Abstract
The ongoing electrification process also requires improvements in the efficiency of power transmission devices, such as transformers, the main part of which is the magnetic core. Despite great progress in the development of core material, losses and audible noise during their operation is [...] Read more.
The ongoing electrification process also requires improvements in the efficiency of power transmission devices, such as transformers, the main part of which is the magnetic core. Despite great progress in the development of core material, losses and audible noise during their operation is still a critical issue to be solved. Currently, a magnetic material used to produce the transformer core is amorphous steel, which is gaining popularity. Compared to traditionally used grain-oriented silicon electrical steel, a significantly larger number of very thin amorphous ribbons is needed to produce the core, which is due to the fact that they are about an order of magnitude thinner, making mechanical stability a challenge. The presented article describes the preparation of a hybrid binder for amorphous steel based on the two types of silanes, tetraethyl orthosilicate and 1,2-bis(triethoxysilyl)ethane, for which their anticorrosive character and good dielectric properties were confirmed. Using the obtained binders, model toroidal cores were produced and their magnetic and acoustic properties were tested. The obtained results indicate that the applied silane-based hybrid binders improved important functional properties by reducing the magnetic no-load losses and audible noise. Full article
(This article belongs to the Special Issue Advances in Properties of Thin Film Materials)
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12 pages, 19666 KiB  
Article
Modulation of Giant Magnetoimpedance Effect in Co-Based Amorphous Wires by Carbon-Based Nanocoatings
by Zhen Yang, Jiabao Huang, Jingyuan Chen and Chong Lei
C 2025, 11(2), 26; https://doi.org/10.3390/c11020026 - 1 Apr 2025
Viewed by 1126
Abstract
Co-based amorphous wires (Co-AWs) are functional materials renowned for their high impedance change rate in magnetic fields and a pronounced giant magnetoimpedance (GMI) effect. In this study, magnetron sputtering (MS) and dip-coating (DC) techniques were employed to fabricate carbon-based nanocoatings aimed at modulating [...] Read more.
Co-based amorphous wires (Co-AWs) are functional materials renowned for their high impedance change rate in magnetic fields and a pronounced giant magnetoimpedance (GMI) effect. In this study, magnetron sputtering (MS) and dip-coating (DC) techniques were employed to fabricate carbon-based nanocoatings aimed at modulating the GMI properties of Co-AWs. The magnetic properties and GMI responses of the composite Co-AWs with carbon-based coatings were comparatively analyzed. The results demonstrate that both methods effectively enhanced the GMI properties of the coated Co-AWs. The DC method emerged as a rapid and efficient approach for forming the coated film, achieving a modest enhancement in GMI performance (10% enhancement). In contrast, the MS technique proved more effective in improving the GMI effect, yielding superior results. Co-AWs coated via Ms exhibited smoother surfaces and reduced coercivity. Notably, the GMI effect increased with the thickness of the sputtered carbon coatings, reaching a maximum GMI effect of 522% (a remarkable 357% enhancement) and a sensitivity of 33.8%/Oe at a coating thickness of 334 nm. The observed trend in the GMI effect with carbon layer thickness corresponded closely to variations in transverse permeability, as determined by vibrating sample magnetometry (VSM). Furthermore, the carbon coating induced changes in the initial quenching stress on the surface of the Co-AWs, leading to alterations in impedance and a significant reduction in the characteristic frequency of the Co-AWs. Our findings provide valuable insights into the modulation of GMI properties in Co-AWs, paving the way for their optimized application in advanced magnetic sensor technologies. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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14 pages, 7361 KiB  
Article
Improving the Soft Magnetic Characteristics of Nanocrystalline Soft Magnetic Composites Through the Incorporation of Ultrafine FeSiAl Powders
by Yanyan Song, Zhi Zhang, Shaoxiong Zhou, Ruibiao Zhang, Haichen Yu and Xiantao Li
Magnetochemistry 2025, 11(4), 25; https://doi.org/10.3390/magnetochemistry11040025 - 30 Mar 2025
Cited by 1 | Viewed by 1062
Abstract
Nanocrystalline powders, characterized by a biphasic amorphous nanocrystalline structure, demonstrate outstanding soft magnetic characteristics, including reduced coercivity (Hc), enhanced effective permeability (μe), and increased resistivity. However, their high hardness, poor formability, and significant core loss (P [...] Read more.
Nanocrystalline powders, characterized by a biphasic amorphous nanocrystalline structure, demonstrate outstanding soft magnetic characteristics, including reduced coercivity (Hc), enhanced effective permeability (μe), and increased resistivity. However, their high hardness, poor formability, and significant core loss (Pcv) restrict their use in high-performance molded inductors. In this study, FeSiBCuNb/FeSiAl nanocrystalline soft magnetic composites (NSMCs) were fabricated, and the influence of varying the FeSiAl concentration on the microstructure, density, and soft magnetic characteristics of NSMCs was investigated. Then, the underlying mechanisms of these effects were explained. The results demonstrate that FeSiAl exhibits apparent deformation following compression, effectively filling the air gap between the FeSiBCuNb powder particles, thereby enhancing coupling among the magnetic particles. Consequently, the density of the NSMCs was enhanced, leading to a significant improvement in their overall soft magnetic properties. When 50 wt.% FeSiAl is added, the NSMCs display outstanding magnetic properties, including a low Hc of 4.36 Oe, a high μe of 48.7, a low Pcv of 119.35 kW/m3 at 50 mT and 100 kHz, and a high DC-bias performance of 73.29% at 100 Oe. Compared to NSMCs without FeSiAl, μe increased by 59.4% and Pcv decreased by 66.1%. Meanwhile, the incorporation of ultrafine FeSiAl powder was found to significantly improve the material properties, as the deformable FeSiAl particles effectively fill interparticle gaps during compaction, enhancing density and magnetic coupling. The 50 wt.% FeSiAl composition demonstrated exceptional properties. These advances address critical challenges in high-frequency power electronic applications and provide a practical material solution for next-generation power electronics. Full article
(This article belongs to the Section Magnetic Materials)
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23 pages, 8944 KiB  
Review
Stress-Induced Magnetic Anisotropy in Fe-Based Amorphous/Nanocrystalline Alloys: Mechanisms, Advances and Challenges
by Jianqiang Zhang, Yanjun Qin, Xiaobin Liu, Yuxiang Zhao, Wenqiang Dang, Xiaozhen Fan, Xinyi Chen, Yuanrong Yu, Zixuan Yang, Shipeng Gao, Duanqiang Wu and Yunzhang Fang
Materials 2025, 18(7), 1499; https://doi.org/10.3390/ma18071499 - 27 Mar 2025
Viewed by 920
Abstract
Fe-based amorphous and nanocrystalline alloys, such as FINEMET and its improved variants, are highly valued as green energy-saving materials due to their unique magnetic properties, including high permeability, low coercivity, and near-zero saturation magnetostriction. These characteristics have enabled their extensive use in power [...] Read more.
Fe-based amorphous and nanocrystalline alloys, such as FINEMET and its improved variants, are highly valued as green energy-saving materials due to their unique magnetic properties, including high permeability, low coercivity, and near-zero saturation magnetostriction. These characteristics have enabled their extensive use in power electronics and information technology. However, the full potential of these alloys remains unfulfilled due to insufficient understanding of their stress sensitivity. This study focuses on the development history, heat treatment, annealing processes, chemical composition, and underlying mechanisms of Fe-based amorphous and nanocrystalline alloys, aiming to provide insights into stress-induced magnetic anisotropy and guide the development of greener and more efficient soft magnetic materials. Full article
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14 pages, 3350 KiB  
Article
Optimization Study of Rare Earth-Free Metal Amorphous Nanocomposite Axial Flux-Switching Permanent Magnet Motor
by Kyle P. Schneider, Satoru Simizu, Michael E. McHenry and Maarten P. de Boer
Energies 2025, 18(3), 640; https://doi.org/10.3390/en18030640 - 30 Jan 2025
Viewed by 1057
Abstract
Metal amorphous nanocomposite (MANC) soft magnetic materials exhibit remarkably low iron loss and high saturation magnetization. However, they have not been widely used in electric motors largely due to a lack of demonstrated manufacturing processing methods and an absence of proven motor designs [...] Read more.
Metal amorphous nanocomposite (MANC) soft magnetic materials exhibit remarkably low iron loss and high saturation magnetization. However, they have not been widely used in electric motors largely due to a lack of demonstrated manufacturing processing methods and an absence of proven motor designs well suited for their use. Recent developments in these two areas have prompted the optimization study of flux-switching with permanent magnet motor topology using MANCs presented here. This study uses population-based optimization in conjunction with a simplified electromagnetics model to seek rare earth-free designs that attain or exceed the state of the art in power density and efficiency. To predict the maximum mechanically safe rotational speed for each design with minimal computational effort, a new method of quantifying the rotor assembly mechanical limit is presented. The resulting population of designs includes motor designs with a specific power of up to 6.1 kW/kg and efficiency of up to 99% without the use of rare earth permanent magnets. These designs, while exhibiting drawbacks of high electrical frequency and significant manufacturing complexity, exceed the typical power density of representative state-of-the-art EV motors while increasing efficiency and eliminating rare earth elements. Full article
(This article belongs to the Special Issue Advances in Permanent Magnet Motor and Motor Control)
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31 pages, 6043 KiB  
Review
Low-Loss Soft Magnetic Materials and Their Application in Power Conversion: Progress and Perspective
by Weiwang Wang, Jiaqi Fan, Changshen Li, Yue Yu, Anding Wang, Shengtao Li and Jinjun Liu
Energies 2025, 18(3), 482; https://doi.org/10.3390/en18030482 - 22 Jan 2025
Cited by 2 | Viewed by 2851
Abstract
Amorphous and nanocrystalline alloys, as novel soft magnetic materials, can enable high efficiency in a wide range of power conversion techniques. Their wide application requires a thorough understanding of the fundamental material mechanisms, typical characteristics, device design, and applications. The first part of [...] Read more.
Amorphous and nanocrystalline alloys, as novel soft magnetic materials, can enable high efficiency in a wide range of power conversion techniques. Their wide application requires a thorough understanding of the fundamental material mechanisms, typical characteristics, device design, and applications. The first part of this review briefly overviews the development of amorphous and nanocrystalline alloys, including the structures of soft magnetic composites (SMCs), the key performance, and the underlying property-structure correction mechanisms. The second part discusses three kinds of high-power conversion applications of amorphous and nanocrystalline alloys, such as power electronics transformers (PETs), high-power inductors, and high-power electric motors. Further detailed analysis of these materials and applications are reviewed. Finally, some critical issues and future challenges for material tailoring, device design, and power conversion application are also highlighted. Full article
(This article belongs to the Section F3: Power Electronics)
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14 pages, 2541 KiB  
Article
Magnetoelastic Effect in Ni-Zn Ferrite Under Torque Operation
by Jacek Salach, Maciej Kachniarz, Dorota Jackiewicz and Adam Bieńkowski
Materials 2024, 17(24), 6239; https://doi.org/10.3390/ma17246239 - 20 Dec 2024
Viewed by 784
Abstract
The magnetoelastic effect is known as the dependence between the magnetic properties of the material and applied mechanical stress. The stress might not be applied directly but rather generated by the applied torque. This creates the possibility of developing a torque-sensing device based [...] Read more.
The magnetoelastic effect is known as the dependence between the magnetic properties of the material and applied mechanical stress. The stress might not be applied directly but rather generated by the applied torque. This creates the possibility of developing a torque-sensing device based on the magnetoelastic effect. In this paper, the concept of an axially twisted toroidal magnetic core as a torque-sensing element is considered. Most known works in this field consider the utilization of an amorphous ribbon as the core material. However, Ni-Zn ferrites, exhibiting relatively high magnetostriction, also seem to be promising materials for magnetoelastic torque sensors. This paper introduces a theoretical description of the magnetoelastic effect under torque operation on the basis of total free energy analysis. The methodology of torque application to the toroidal core, utilized previously for coiled cores of amorphous ribbons, was successfully adapted for the bulk ferrite core. For the first time, the influence of torque on the magnetic properties of Ni-Zn ferrite was investigated in a wide range of magnetizing fields. The obtained magnetoelastic characteristics allowed the specification of the magnetoelastic torque sensitivity of the material and the determination of the optimal amplitude of the magnetizing field to maximize this parameter. High sensitivity, in comparison with previously studied amorphous alloys, and monotonic magnetoelastic characteristics indicate that the investigated Ni-Zn ferrite can be utilized in magnetoelastic torque sensors. As such, it can be used in torque-sensing applications required in mechanical engineering or civil engineering, like the evaluation of structural elements exposed to torsion. Full article
(This article belongs to the Collection Magnetoelastic Materials)
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27 pages, 14209 KiB  
Article
Statistical and Block Copolymers of n-Dodecyl and Allyl Isocyanate via Titanium-Mediated Coordination Polymerization: A Route to Polyisocyanates with Improved Thermal Stability
by Maria Iatrou, Aikaterini Katara, Panagiotis A. Klonos, Apostolos Kyritsis and Marinos Pitsikalis
Polymers 2024, 16(24), 3537; https://doi.org/10.3390/polym16243537 - 19 Dec 2024
Viewed by 936
Abstract
Well-defined amorphous/semi-crystalline statistical copolymers of n-dodecyl isocyanate, DDIC, and allyl isocyanate, ALIC, were synthesized via coordination polymerization using the chiral half-titanocene complex CpTiCl2(O-(S)-2-Bu) as an initiator. In the frame of the terminal model, the monomer reactivity ratios of the statistical copolymers [...] Read more.
Well-defined amorphous/semi-crystalline statistical copolymers of n-dodecyl isocyanate, DDIC, and allyl isocyanate, ALIC, were synthesized via coordination polymerization using the chiral half-titanocene complex CpTiCl2(O-(S)-2-Bu) as an initiator. In the frame of the terminal model, the monomer reactivity ratios of the statistical copolymers were calculated using both well-known linear graphical methods and the computer program COPOINT. The molecular and structural characteristics of the copolymers were also calculated. The thermal properties of these samples were studied by differential scanning calorimetry, DSC, measurements. The kinetics of the thermal decomposition of the statistical copolymers was studied by thermogravimetric analysis, TGA, and differential thermogravimetry, DTG, and the activation energy of this process was calculated by employing several theoretical models. Moreover, block copolymers with the structure P[DDIC-b-(DDIC-co-ALIC)] were synthesized by sequential addition of monomers and coordination polymerization methodologies. The samples were characterized by nuclear magnetic resonance, NMR, spectroscopy; size exclusion chromatography, SEC; and DSC. The thermal stability of the blocks was also studied by TGA and DTG and compared to the corresponding statistical copolymers, showing that the macromolecular architecture greatly affects the properties of the copolymers. A thiol-ene click post-polymerization reaction was performed to introduce aromatic groups along the polyisocyanate chain in order to improve the thermal stability of the parent polymers. Evidently, these statistical and block copolymers can be employed as precursors for the synthesis of novel polyisocyanate-based materials. Full article
(This article belongs to the Special Issue Emerging Trends in Polymer Engineering: Polymer Connect-2024)
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12 pages, 3149 KiB  
Article
Fine-Grained High-Permeability Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Mo or W) Nanocrystalline Alloys with Co-Added Heterogeneous Transition Metal Elements
by Su-Bong An, Hyun-Ah Im, Young-Tae Kwon, Jung-Woo Lee and Jae-Won Jeong
Metals 2024, 14(12), 1424; https://doi.org/10.3390/met14121424 - 12 Dec 2024
Cited by 2 | Viewed by 1055
Abstract
This study investigates the effects of multi-transition metals on the soft magnetic properties of Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Nb, Mo, and W) nanocrystalline soft magnetic alloys. Nanocrystalline soft magnetic materials are [...] Read more.
This study investigates the effects of multi-transition metals on the soft magnetic properties of Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Nb, Mo, and W) nanocrystalline soft magnetic alloys. Nanocrystalline soft magnetic materials are utilized in electronic components on the basis of their permeability and low core loss. In conventional alloys such as FINEMET, Nb inhibits nanocrystal growth and promotes amorphous formation. In this research, Mo and W were used as additional transition metals to control the size of nanocrystals and explore the potential for enhancing soft magnetic properties. We confirmed that the addition of Mo and W reduced the nanocrystal size, and the activation energy for nanocrystal formation and growth showed significant benefits for nanocrystalline alloys. Consequently, the soft magnetic properties of the alloys containing Mo and W exhibited higher permeability and lower coercivity. These results suggest that multi-transition metals are effective in improving soft magnetic properties by inhibiting nanocrystal formation and growth. Full article
(This article belongs to the Special Issue Metallic Magnetic Materials: Manufacture, Properties and Applications)
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22 pages, 11317 KiB  
Article
Exploring 3D Printing in Drug Development: Assessing the Potential of Advanced Melt Drop Deposition Technology for Solubility Enhancement by Creation of Amorphous Solid Dispersions
by Nabil Lamrabet, Florian Hess, Philip Leidig, Andreas Marx and Thomas Kipping
Pharmaceutics 2024, 16(12), 1501; https://doi.org/10.3390/pharmaceutics16121501 - 22 Nov 2024
Viewed by 2807
Abstract
Background: Melt-based 3D printing technologies are currently extensively evaluated for research purposes as well as for industrial applications. Classical approaches often require intermediates, which can pose a risk to stability and add additional complexity to the process. The Advanced Melt Drop Deposition (AMDD) [...] Read more.
Background: Melt-based 3D printing technologies are currently extensively evaluated for research purposes as well as for industrial applications. Classical approaches often require intermediates, which can pose a risk to stability and add additional complexity to the process. The Advanced Melt Drop Deposition (AMDD) technology, is a 3D printing process that combines the principles of melt extrusion with pressure-driven ejection, similar to injection molding. This method offers several advantages over traditional melt-based 3D printing techniques, making it particularly suitable for pharmaceutical applications. Objectives: This study evaluates the AMDD printing system for producing solid oral dosage forms, with a primary focus on the thermo-stable polymer polyvinyl alcohol (PVA). The suitability of AMDD technology for creating amorphous solid dispersions (ASDs) is also examined. Finally, the study aims to define the material requirements and limitations of the raw materials used in the process. Methods: The active pharmaceutical ingredients (APIs) indometacin and ketoconazole were used, with PVA 4-88 serving as the carrier polymer. Powders, wet granulates, and pellets were investigated as raw materials and characterized. Dissolution testing and content analyses were performed on the printed dosage forms. Solid-state characterization was conducted using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Degradation due to thermal and mechanical stress was analyzed using nuclear magnetic resonance spectroscopy (NMR). Results/Conclusions: The results demonstrate that the AMDD 3D printing process is well-suited for producing solid dosage forms. Tablets were successfully printed, meeting mass uniformity standards. Adjusting the infill volume from 30% to 100% effectively controlled the drug release rate of the tablets. Solid-state analysis revealed that the AMDD process can produce amorphous solid dispersions with enhanced solubility compared to their crystalline form. The experiments also demonstrated that powders with a particle size of approximately 200 µm can be directly processed using AMDD technology. Full article
(This article belongs to the Special Issue Impact of Raw Material Properties on Solid Dosage Form Processes)
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