Metals

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14 pages, 6509 KiB

Open AccessArticle

Preparation and Antibiosis Investigation of Kaolinite Nanotubes and Silver Nanowires Co-Doped Electrospinning-Silk Fibroin/Gelatin Porous Fiber Films

by Jiamin Xiao, Yanfang Li, Jianliang Wang, Yizhe Xu, Guoren Zhang and Chongyan Leng

Metals 2023, 13(4), 745; https://doi.org/10.3390/met13040745 - 11 Apr 2023

Cited by 2 | Viewed by 1201

Abstract

Skin wounds are one of the most common injuries for the human body; they can lead to an infection and cause tissue necrosis and even life-threatening injuries. Therefore, it is an urgent task to develop skin scaffold materials to meet the various needs [...] Read more.

Skin wounds are one of the most common injuries for the human body; they can lead to an infection and cause tissue necrosis and even life-threatening injuries. Therefore, it is an urgent task to develop skin scaffold materials to meet the various needs of restoring skin’s structural integrity. In this research, kaolinite nanotubes and silver nanowires co-doped silk fibroin and gelatin composite porous fiber films were fabricated by an electrospinning method. The composition, micrograph, chemical states of elements included, biocompatibility, and antimicrobial properties of the samples produced were analyzed. After co-doping kaolinite nanotubes and silver nanowires, the fiber diameter of the porous fiber films became uniform, and the beads in the film were reduced significantly. The silk fibroin/gelatin/kaolinite nanotubes/silver nanowire (SF/GEL/KA-N/AgNWs) film shows antibacterial activity against S. aureus and E. coli, and the antibacterial rings were 7.42 mm and 5.76 mm, respectively. All the films were free of cytotoxicity and provided good biocompatibility, which is a great clinical application potential in skin. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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13 pages, 5182 KiB

Open AccessArticle

Electrooxidation Performance of a Cotton-Cloth-Derived, Ni-Based, Hollow Microtubular Weave Catalytic Electrode for Methanol and Urea

by Guangya Hou, Jiaxuan Wei, Qiang Chen, Jianli Zhang and Yiping Tang

Metals 2023, 13(4), 659; https://doi.org/10.3390/met13040659 - 26 Mar 2023

Viewed by 1461

Abstract

Increasing consumption produces a large amount of cotton textile waste, the conversion of which into porous metals used for energy purposes is of practical value. In this paper, a porous, Ni-based, hollow microtubular weave (Ni-HTW) is obtained from cotton weave by high-temperature carbonization [...] Read more.

Increasing consumption produces a large amount of cotton textile waste, the conversion of which into porous metals used for energy purposes is of practical value. In this paper, a porous, Ni-based, hollow microtubular weave (Ni-HTW) is obtained from cotton weave by high-temperature carbonization and hydrothermal synthesis with high-temperature reduction. The Ni-based, hollow microtubules in this weave have a diameter of 5–10 μm and a wall thickness of about 1 μm, and every 15 microtubules form a loose bundle with a diameter of 150–200 μm. For improved performance, Ni(OH)₂ nanosheets are further electrodeposited on the fibers’ surface of the Ni-HTW to form a nano-Ni(OH)₂/Ni-HTW composite electrode with a core–shell heterostructure where Ni is the core and Ni(OH)₂ the shell. The combination of hollow microtubule weave morphology and nanosheet structure results in a large specific surface area and abundant active sites, and the composite electrode shows excellent electrocatalytic performance and long-term stability for methanol oxidation (MOR) and urea oxidation (UOR). The current densities can reach 303.1 mA/cm² and 342.5 mA/cm² at 0.8 V, and 92.29% (MOR) and 84.41% (UOR) of the pre-cycle current densities can be maintained after 2000 consecutive cycles. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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15 pages, 6635 KiB

Open AccessFeature PaperArticle

Functional Behaviour of Cold-Worked and Straight-Annealed NiTi Elements Processed with Ultrashort Laser Cutting

by Carlo Alberto Biffi and Ausonio Tuissi

Metals 2023, 13(1), 16; https://doi.org/10.3390/met13010016 - 22 Dec 2022

Viewed by 1274

Abstract

Among functional materials, quasiequiatomic NiTi alloys are one of the most promising and diffused for some sectors, from the biomedical to aerospace ones. Their peculiar performance, namely, shape memory effect and pseudoelasticity, is induced via a thermomechanical treatment called shape setting or with [...] Read more.

Among functional materials, quasiequiatomic NiTi alloys are one of the most promising and diffused for some sectors, from the biomedical to aerospace ones. Their peculiar performance, namely, shape memory effect and pseudoelasticity, is induced via a thermomechanical treatment called shape setting or with the heat treatment of annealing. This heat treatment is carried out in cold-worked conditions. The present work studies the effect of the material conditions of straight annealing and cold working on the functional performance of diamond-shaped NiTi microdevices realised through ultrashort laser cutting. In detail, experiments were carried out aimed at studying the effect of laser power, scanning speed, and number of passes on the kerf width with the focus on defining the most suitable process condition on both straight-annealed and cold-worked sheets of 100 µm in thickness. After the process parameters had been defined, the transformation temperatures and superelastic behaviour were analysed though differential scanning calorimetry and force–displacement testing. The femtosecond cutting of straight-annealed NiTi did not change the characteristic temperatures of the base material, while the same process induced a soft martensitic transformation with respect to the cold-worked material due to a heat accumulation effect. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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10 pages, 3652 KiB

Open AccessArticle

Effects of Electrolytic Copper Foil Roughness on Lithium-Ion Battery Performance

by Jianli Zhang, Dengyu Zuo, Xiaozhe Pei, Chengfa Mu, Keyu Chen, Qiang Chen, Guangya Hou and Yiping Tang

Metals 2022, 12(12), 2110; https://doi.org/10.3390/met12122110 - 8 Dec 2022

Cited by 6 | Viewed by 3100

Abstract

Improving the interfacial properties between the electrode materials and current collectors plays a significant role in lithium-ion batteries. Here, four kinds of electrolytic copper foils with roughness (Rz) values of 1.2, 1.5, 2.2, and 2.8 μm were prepared via an electropolishing technique. Reducing [...] Read more.

Improving the interfacial properties between the electrode materials and current collectors plays a significant role in lithium-ion batteries. Here, four kinds of electrolytic copper foils with roughness (Rz) values of 1.2, 1.5, 2.2, and 2.8 μm were prepared via an electropolishing technique. Reducing the roughness of the electrolytic copper foil can effectively improve the wettability of the anode slurry. The electrolytic copper foil with a roughness value of 1.2 μm shows the best coating uniformity of the graphite anode slurry. The battery with this electrolytic copper foil (Rz = 1.2 μm) as the current collector exhibits fifth-cycle capacities of 358.7 and 102.5 mAh g⁻¹ at 0.2 and 3.0 C, respectively, showing excellent rate capability. In addition, at 0.5 C, the battery exhibits an initial discharge capacity of 319.5 mAh g⁻¹ and a 100th-cycle capacity retention rate of 98.1%, demonstrating a high level of cycling performance. These results indicate that reducing the roughness of electrolytic copper foil can provide a feasible route to improve the performance of lithium-ion batteries. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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12 pages, 13716 KiB

Open AccessArticle

Microstructure and Mechanical Properties of ZL205A Aluminum Alloy Produced by Squeeze Casting after Heat Treatment

by Hong Jiang, Linfan Zhang, Biwei Zhao, Ming Sun and Meifeng He

Metals 2022, 12(12), 2037; https://doi.org/10.3390/met12122037 - 26 Nov 2022

Cited by 4 | Viewed by 1580

Abstract

In this paper, ZL205A (AlCu5Mn alloy) castings were prepared by squeeze casting. The effects of solution and ageing treatment on the microstructure and mechanical properties of ZL205A castings were studied by metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and mechanical properties [...] Read more.

In this paper, ZL205A (AlCu5Mn alloy) castings were prepared by squeeze casting. The effects of solution and ageing treatment on the microstructure and mechanical properties of ZL205A castings were studied by metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and mechanical properties tests. The results showed that most of the θ(Al₂Cu) and T(Al₁₂CuMn₂) phases in squeeze-cast ZL205A dissolved into the α(Al) matrix after solution treatment for 15 h. The fine precipitates gradually increased with the ageing time. The ultimate tensile strength of the specimen aged for 6 h was the highest of 467 MPa and the elongation was up to 15.1%, showing good comprehensive mechanical properties. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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16 pages, 9629 KiB

Open AccessArticle

Effect of Varying Ce Content on the Mechanical Properties and Corrosion Resistance of Low-Elastic-Modulus Mg-Zn-Ce Amorphous Alloys

by Meifeng He, Mingming Wang, Ke Zhang, Haitao Wang, Hong Jiang and Zhanjun Lu

Metals 2022, 12(10), 1637; https://doi.org/10.3390/met12101637 - 29 Sep 2022

Viewed by 1334

Abstract

Magnesium alloys have good biocompatibility because they have mechanical properties similar to those of human bones, are biodegradable, and release non-toxic corrosion products and ions in the human body. In this study, a new type of Mg_70−xZn₃₀Ce_x (x [...] Read more.

Magnesium alloys have good biocompatibility because they have mechanical properties similar to those of human bones, are biodegradable, and release non-toxic corrosion products and ions in the human body. In this study, a new type of Mg_70−xZn₃₀Ce_x (x = 2, 4, 6, and 8) amorphous magnesium alloy was prepared by copper roller melt-spinning, and the corresponding mechanical properties and corrosion resistance were studied. The results showed that when x = 4 and 6, the Mg-Zn-Ce amorphous alloys had decent amorphous forming abilities. The addition of Ce could effectively improve the ductility of the magnesium-based amorphous alloys with an elastic modulus of each sample ranging between 30 and 58 GPa, which was similar to that of human bones; thus, these materials could effectively prevent the stress shielding effect caused by excessive elastic modulus after implantation. Additionally, the addition of an adequate amount of Ce significantly improved the corrosion resistance of the alloy. The experimental results showed that the best corrosion resistance of the magnesium-based amorphous alloys was achieved when x = 6. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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7 pages, 4004 KiB

Open AccessArticle

Structural Evolution of Bulk Silver during Cold Rolling and Annealing

by Zheda Ning, Qunshou Wang, Dong Zhao, Wenli Pei and Ming Wen

Metals 2022, 12(9), 1525; https://doi.org/10.3390/met12091525 - 15 Sep 2022

Cited by 2 | Viewed by 1391

Abstract

Sputtering target is commonly used in semiconductor manufacturing for the preparation of thin films. Cold rolling and annealing treatment of bulk Ag is the routine process to prepare Ag sputtering target. In this paper, the microstructure evolution of Ag after cold rolling and [...] Read more.

Sputtering target is commonly used in semiconductor manufacturing for the preparation of thin films. Cold rolling and annealing treatment of bulk Ag is the routine process to prepare Ag sputtering target. In this paper, the microstructure evolution of Ag after cold rolling and annealing treatment was studied, and the results showed that annealing temperature affects the recrystallized structure of Ag and that 600 °C/1 h treatment can achieve complete recrystallization. At the same time, the texture evolution was also observed and discussed. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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10 pages, 7205 KiB

Open AccessArticle

Gram-Scale Synthesis of Carbon-Supported Sub-5 nm PtNi Nanocrystals for Efficient Oxygen Reduction

by Minli Wang, Xu Chen, Wenwen Xu, Zhongfeng Wang, Peilei He and Zhiyi Lu

Metals 2022, 12(7), 1078; https://doi.org/10.3390/met12071078 - 23 Jun 2022

Cited by 3 | Viewed by 1581

Abstract

The preparation of a high performance and durability with low-platinum (Pt) loading oxygen reduction catalysts remains a challenge for the practical application of fuel cells. Alloying Pt with a transition metal can greatly improve the activity and durability for oxygen reduction reaction (ORR). [...] Read more.

The preparation of a high performance and durability with low-platinum (Pt) loading oxygen reduction catalysts remains a challenge for the practical application of fuel cells. Alloying Pt with a transition metal can greatly improve the activity and durability for oxygen reduction reaction (ORR). In this work, we present a one-pot wet-chemical strategy to controllably synthesize carbon supported sub-5 nm PtNi nanocrystals with a ~3% Pt loading. The as-prepared PtNi/C-200 catalyst with a Pt/Ni atomic ratio of 2:3 shows a high oxygen reduction activity of 0.66 A mg_pt⁻¹ and outstanding durability over 10,000 potential cycles in 0.1 M KOH in a half-cell condition. The PtNi/C-200 catalyst exhibits the highest ORR activity, with an onset potential (E_onset) of 0.98 V and a half-wave potential (E_1/2) of 0.84 V. The mass activity and specific activity are 3.89 times and 9.16 times those of 5% commercial Pt/C. More importantly, this strategy can be applied to the gram-scale synthesis of high-efficiency electrocatalysts. As a result, this effective synthesis strategy has a significant meaning in practical applications of full cells. Full article

(This article belongs to the Special Issue Metallic Functional Materials)

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