Materials Letters: X最新文献

In today’s scenario, a number of nanocomposites are evidencing handy control in in vitro biological studies like anti-inflammatory and antidiabetic activity. Since the nanocomposite action and mechanism are totally different from others, like simple molecules of antibiotics. This work described a facile one-pot hydrothermal synthesis of the rGO-MnO₂ nanocomposite. The prepared samples were characterized and confirmed by XRD, UV, SEM, EDX, and XPS studies. Furthermore, the catalytic performance evolved through in vitro biological applications such as anti-inflammatory and antidiabetic activities. rGO-MnO₂ nanocomposite has more biological activity than pure MnO₂ nanoparticles, as demonstrated by the results.

Zinc-Nickel Ferrite (Zn_(1−x)Ni_xFe₂O₄) nanoparticles were synthesized by solution combustion method using urea as a fuel and varying the cation concentration (x = 0, 0.2, 0.4, 0.6, 0.8, 1). The effects of cation concentration, on the crystallite size, morphology, absorption properties have been studied. The X-ray diffraction and FTIR results confirm the formation of single-phase spinel structure of Zinc-Nickel Ferrite nanoparticles. FESEM and TEM study reveals the formation of uniform spherical shape distribution of Zn_(1−x)Ni_xFe₂O₄ nanoparticles. The bandgap values were calculated for the prepared samples using UV–Visible spectrophotometer.

Surface-enhanced Raman spectroscopy (SERS) exhibits intriguing analytical application owing to their non-invasive method, specificity, and sensitivity. However, development of tunable SERS active substrate remains a challenge. Herein, we report a straightforward chronoamperometric co-deposition strategy, utilizing a reducing agent, to form bimetallic coating comprised of Cu/Ag on silica substrate, where alteration of deposition current endows fractional variations in the nucleation/growth of Cu²⁺ → Cu⁺/Cu⁰ and Ag²⁺ → Ag⁺/Ag⁰. Properties of optical reflectance, surface chemistry, topography, and nanocrystallite cluster orientation were characterized. Experimental results confirm bimetallic coating with large proportion of Ag on Cu matrix could enable better SERS behavior with studied model, Rhodamine 6G.

This work demonstrates how an interference pattern can improve the performance of remote laser cutting of pure copper foils, making the cutting process effective even for a low power laser source. The proof of concept is carried out by using a nanosecond laser source with a pulse duration of 5 ns, coupled with a two-beam scanning interference setup, producing a spatial period of 12.5 µm. In the experiments, processing parameters as pulse-to-pulse distance, laser power and scanning speed are varied, to optimize the foil breakthrough and their effect on the generated material modifications are investigated. A comparison between the processing results employing the interference pattern and single beam with a Gaussian energy distribution is carried out. While the single beam process is not sufficient for cutting a 10 µm thin metallic foil, the interference treatment shows an improvement over 100%. In addition, only small spatter formations are detected, with average particle sizes of 1.75 ± 0.82 µm on the top side of the foil. The bottom side of a fully separated copper foil only depicts small spatter formations of less than 1 µm.

This article considers the nanoparticles suspended in the gas phase in the vicinity of a 3D-printed surface during additive manufacturing via Laser Beam Powder Bed Fusion (LB-PBF) and Directed Energy Deposition (DED). The results of this research show that the primary pollutants during the laser additive manufacturing using metal powder are aggregated core–shell nanoparticles with an average particle size of about 10 nm. High-resolution microscopy shows the chemical composition of the volume and surface of each particle; in particular, the “core” consists of Fe, Cr, and Ni atoms and the “shell” is a thin oxide layer.

In this study a novel approach was adopted to couple cloisite functionalised with PEO nanoparticles to modify the polyether sulfone (PES) at low pressure nanofiltration membrane for the removal of salts and dyes from waste water. PES/f-(PEO-Cloisite) nanocomposite membranes were fabricated by phase inversion process in presence of DMF as solvent. The functionalised PEO-Cloisite mixture was characterised by SEM-EDX and the membranes were characterised by hydrophilicity and morphology. The highest water flux of 152.77 Lm⁻²h⁻¹ was observed for 4.5 wt% of PEO-Cloisite in PES membrane. Contact angle values reduced from 74.3° to 60.9° with the increase in the concentration of PEO-Cloisite and confirmed the increase of hydrophilicity. The membrane performance was tested using model saline and dye solutions by low pressure nanofiltration under longer run mode. This study infers that modification of PES membranes using functionalised PEO-Cloisite increase the membrane stability can be used to alleviate the fouling in the treatment of industrial waste water.

Uniaxial tensile tests were carried out on nickel sheets containing only few grains across the thickness thus presenting a so-called multicrystalline state. Pristine sheets used as reference and substrates covered by a nickel layer deposited by physical vapor deposition (magnetron sputtering) were studied. Results attest that the surface treatment affects the plastic deformation mechanisms by playing the role of a blocking barrier to dislocation movement which leads to a significant improvement of mechanical performances. The surface restructuring of the nickel sheets is efficient to stop dislocation escape through free surfaces and allows a mechanical improvement of the well-known strong mechanical softening of the multicrystals.

Herein, we report a feasible approach for preparation of crosslinked alginate (Alg) and poly(amido amine) (PAMAM) nanogels (Alg-PAMAM NGs), using a water-in-oil-in-water (w/o/w) double emulsion route, via strong electrostatic interactions between anionic groups coming from alginate and previously incorporated Cu²⁺ ions. CuO nanoparticles (NPs) with average diameter about 65 nm were in situ obtained into Alg/PAMAM nanogels by treatment of embedded Cu²⁺ ions in NGs with NaBH₄ at 25 °C under air atmosphere. The prepared Alg-PAMAM and Alg-PAMAM-CuO NGs were characterized using FT-IR and UV–visible spectroscopy, as well as scanning transmission electron microscopy (STEM). The presence of PAMAM dendrimers helped both to obtain structurally compact nanogels and an adequate stabilization of CuO NPs. Finally, the photocatalytic performance of the Alg-PAMAM-CuO NGs was tested via the decomposition of methyl orange in aqueous solution, under visible light irradiation.

Ga₂O₃ has attracted significant attention for various applications such as power-switching applications and deep-ultraviolet optoelectronics. In this study, we demonstrated a lattice-matching κ-(In_1−xGa_x)₂O₃ thin film grown on an ε-GaFeO₃ substrate via the mist chemical vapor deposition process. The X-ray diffraction peak of the thin film was almost coincident with that of the substrate and exhibited Laue oscillations. Atomic force microscopy revealed that the surface of the κ-(In_1−xGa_x)₂O₃ thin film exhibited a step-terrace morphology and was atomically flat. The selected area electron diffraction of transmission electron microscopy showed that the diffraction spots of the thin film and substrate overlapped, indicating that the thin film was almost lattice-matched with the substrate. We believe that the lattice-matched κ-(In_1−xGa_x)₂O₃ thin film with an ε-GaFeO₃ substrate will contribute significantly to the demonstration of ferroelectric κ-Ga₂O₃ based high electron mobility transistors.

Aiming to improve the surface properties of copper, a Ni-Cr-B-Si coating was fabricated by plasma transferred arc (PTA) cladding. The coating formed a good metallurgical bonding with the copper substrate, and the dilution rate was about 15.9%. The coating mainly contained γ-(Cu, Fe, Ni), Cr₂₃C₆, CrB and Ni₃Si phases, which played a role of solid solution strengthening and dispersion strengthening. The hardness of the coating was significantly improved compared to the copper substrate, which was approximately 7.8 times that of the substrate. The wear resistance of the coating was 5.0 times higher than that of the copper substrate, and the wear mechanism was abrasive wear.