查看更多>>摘要：? 2022 Elsevier B.V.In view of the interest that (Fe,Co)2(P,Si) compounds have as potential permanent magnets, their structural and magnetic phase diagrams are explored focusing on establishing the range where the hexagonal Fe2P-type structure is observed. In Fe1.93-xCoxP1-ySiy, the highest Si content prior entering a mixed phase domain is y ≈ 0.5. At high Si content but low Co for Fe substitutions, a structural distortion leading to a body-centered orthorhombic structure occurs. At high Co contents, when the Fe2P unit cell reaches a critical volume of about 102.4 ?3, the samples crystallize in a Co2P-type orthorhombic structure. Within the Fe2P-type structural range, the evolution of the unit-cell volume appears to follow the Vegard's law, but this hides strongly anisotropic changes. Simultaneous Co for Fe and Si for P substitutions increase the range where the hexagonal structure is observed in comparison to ternary Fe2(P,Si) and (Fe,Co)2P. The samples are ferromagnetic, but with Curie temperatures showing an unusual evolution, uncorrelated to the c/a ratio of the lattice parameters. At low Si content, TC increases with Co for Fe substitutions. For y = 0.2, the evolution is not significant, while at high Si content TC systematically decreases with the increase in Co. Large Si and Co substitutions lead to a swift weakening of the magnetocrystalline anisotropy until the easy axis anisotropy turns from the c axis toward the a-b plane. This study guides future investigations by restricting the range where desirable properties for permanent magnetic applications can be expected to 0.1 ? x ? 0.3 and 0.1 ? y ? 0.3.
查看更多>>摘要：? 2022 The AuthorsIt is known that Cu-Sn alloy is difficult to hot working due to Sn segregation which occurs during solidification. Sn segregation is formed at grain boundary and it acts as crack initiation site during hot working. To suppress Sn segregation at grain boundary, density functional theory calculations were performed to search the proper elements that can stabilize Sn in Cu matrix. Based on the simulations, Co-Sn pairs are the most stable in Cu matrix, meaning that Co atoms can effectively stabilize Sn atoms in Cu matrix. To enhance the Co effect, we search the additional element to stabilize Co atom in Cu. As a result, Co atoms can stabilize more in form of Co-Ti pair in Cu. Three alloys, Cu-8Sn-0.1 P alloy (wt%), this alloy with 0.23 Co and 0.18 Ti, and alloy with 0.45 Co and 0.36 Ti were prepared. Co and Ti addition in Cu-Sn-P alloy formed the Co-Ti intermetallic compound and improved the uniformity of Sn concentration in matrix and lead reducing the Sn segregation at grain boundary. The reduction of Sn concentration difference in matrix resulted in uniform deformation and prevented crack initiation during high temperature deformation. As a result, Cu-Sn-P alloy with Co and Ti alloy prevented cracking after a hot compression test or hot rolling at 850 °C.
查看更多>>摘要：? 2022 Elsevier B.V.In this paper, the experimental results for binary alloys of gallium with indium melting plateau realization are reported. The Ga-In eutectic plateaus can last for more than 80 h with a temperature change of less than 1.5 mK. Various methods were employed to accurately determine the phase transition point of the Ga-In eutectic. By calculation, the point of inflection (POI) manner shows the best performance and is recommended for the determination of the Ga-In eutectic phase transition point. By repeatedly realising Ga-In eutectic melting plateaus, the melting point temperature was determined to be 15.6479 °C, with a reproducibility of less than 0.14 mK. The corresponding realization uncertainty of Ga-In eutectic was also analyzed and was found to be 0.90 mK (k = 2). These results are consistent with those of previous studies within the associated uncertainties and will help better understand the phase diagram and the corresponding thermal properties of the Ga-In eutectic.
查看更多>>摘要：? 2022 Elsevier B.V.The effect of annealing on the chemical partitioning, microstructural evolution, and magnetic properties of a magnetron sputter deposited Co-2.8Fe-2.7Mn-3.5-Nb-2.4Si-7.2B (at%) alloy was investigated using transmission electron microscopy, atom probe tomography, and vibrating-sample magnetometry. While no crystallinity was observed in the as-deposited film, nonideal mixing in this amorphous state was noted by the Mn enrichment around the film's ~ 7 nm diameter columnar morphology that spanned the thickness of the film parallel to the growth direction. Following annealing at 520 °C for either 5 min or 20 min, the columnar morphology transformed to a partially crystallised microstructure with Co and Fe enriching 7.0 ± 1.4 nm crystallites encased by an amorphous region enriched with Nb, B, Si, and Mn. The magnetic coercivity, ~ 26 Oe, was invariant upon annealing while the saturation magnetisation increased from 828 to 953 emu/cm3.
查看更多>>摘要：? 2022 Elsevier B.V.The development of effective catalysts is crucial for refractory antibiotics pollutants removal. A visible light-driven δ-FeOOH/BiOBrxI1?x photocatalyst for the tetracycline (TC) degradation was fabricated and a photocatalysis-Fenton synergy system was formed in the presence of H2O2. δ-FeOOH/BiOBrxI1?x indicated better photo-Fenton catalytic activity and good cycle stability under visible light irradiation. Especially, δ-FeOOH/BiOBr0.5I0.5 exhibited the highest photo-Fenton catalytic activity and the removal efficiency of TC was 93% within 1 h, which was 1.63 times of the degradation efficiency of photocatalysis alone. This could be attributed to the synergistic effects of δ-FeOOH and BiOBr0.5I0.5, which promoted the separation of the photoinduced charge carriers and thus improved the photo-Fenton performance. Meanwhile, the presence of H2O2 enabled the conversion between Fe2+ and Fe3+. In addition, the ?O2?and ?OH active radicals were confirmed to greatly accelerate the degradation of TC and the possible mechanism was revealed. This study might provide a promising candidate for the development of effective catalyst in the treatment of antibiotic wastewaters.
查看更多>>摘要：? 2022 Elsevier B.V.The effects of metastability engineering on tuning deformation behavior and deformation mechanisms in TiZrHfTaX (x = 1.00, 0.80, 0.60, 0.50) refractory body-centered cubic (BCC) high entropy alloys were investigated, with specific emphasis on elucidating the underlying interplay between phase stability, mechanical property, and deformation twins. It was found that in proper thermomechanical treated samples, a variation of tantalum content can effectively tune the activation of various deformation mechanisms. Detailed electron back-scattered diffraction and transmission electron microscopy analyses revealed for the first time that {332}<113?>BCC twinning, deformation-induced α’’ phase, {111}α’’ type I and <2?11>α’’ type II twinning can be sequentially activated in TiZrHfTaX (x = 1.00, 0.80, 0.60, 0.50) high entropy alloys with decreasing the content of tantalum. The comprehensive strengthening effect of transformation induced plasticity and twinning induced plasticity, was discussed and attributed as the pivotal factor for the improved work hardening capability and mechanical performances, especially for alloys with lower tantalum contents. Consequently, we extended the conventional bond order and d‐orbital energy level diagram that was originally developed for body-centered cubic titanium alloys for deformation mechanism evaluation to body-centered cubic high entropy alloys on the basis of current results, which sheds light on the design of ductile body-centered cubic high entropy alloys with expected deformation mechanisms and optimized mechanical performance.
查看更多>>摘要：? 2022 Elsevier B.V.To improve the flexibility of transparent conductive electrodes (TCEs), we designed multi-stacked ITO/PEDOT:PSS hybrid superlattice (IxPy) films for flexible polymer-dispersed liquid crystal (PDLC), foldable thin-film heaters (TFHs), and flexible perovskite solar cells (PSCs). The electrical and optical properties of the multi-stacked IxPy films were examined and then optimized at the I6P5 film (ITO: 6 layers and PEDOT: 5 layers). The I6P5 film showed a sheet resistance of 149.66 Ohm/square, high transmittance of 93.75% at the visible range of (400–800) nm, and achieved the highest figure-of-merit (FOM) value of 3.50 × 10?3, compared with the other stacked conditions. Furthermore, the I6P5 films showed better flexibility by suppressing the brittle nature of ITO through inserting very thin PEDOT:PSS. The I6P5 film as an electrode was employed as a flexible PDLC, flexible TFHs, and flexible PSCs. The I6P5-based PDLC showed a clear distinction between on-state and off-state. At the applied voltage of 60 V, the transmittance of PDLC increased to 48.829% because of the arrangement of liquid crystals in the current direction. The flexible TFHs with I6P5 superlattice electrode showed high saturation temperature of above 100 °C at 14 V. Moreover, the I6P5 electrodes showed similar efficiency to reference ITO films in flexible PSCs. These results indicate that the multi-stacked IxPy hybrid superlattice films offer superior potential as highly transparent and foldable or flexible conductive electrodes.
查看更多>>摘要：? 2022 Elsevier B.V.The modification of graphite carbonitride (g-C3N4) is beneficial to increase its specific surface area and high quantum efficiency, thus improving its activity. Herein, the Yb2O3/g-C3N4 composites were adjusted through dual regulation synergistically (nanostructure design of g-C3N4 and addition of lanthanide oxides Yb2O3) to improve the photocatalytic performance of hydrogen production and NO removal simultaneously. The as-prepared 1% Yb2O3/tubular g-C3N4 could efficiently promote the photocatalytic hydrogen evolution (4071.763 μmol·g?1·h?1) and NO removal performance (54.20%), which was approximately 8.85 times and 32.01% higher respectively than that of bulk g-C3N4 prepared by melamine (g-C3N4-M). The formation process of·O2- and·OH radicals and the oxidation process of NO had been systematically studied through ESR and in-situ DRIFTS, which proved that the coupling of tubular g-C3N4 with Yb2O3 had a positive effect. This work provided a novel strategy for dual regulation (adjust morphology and metal oxide introduction) synergistically design of bifunctional photocatalysts to enhance H2 production and NO removal simultaneously.
查看更多>>摘要：? 2022 Elsevier B.V.The exploration of photocatalytic hydrogen evolution from solar water splitting under influence of sacrificial agents and proton sources has given us interesting ideas on related challenges. In this paper, we have studied the superior effect of methanol and aniline hydrochloride on photocatalytic hydrogen evolution by cactus-type bpydc@Fe2O3/TiO2 hybrid nanomaterials from solar water splitting. The bandgap of TiO2 has been tuned by the composite formation using organic bpydc and inorganic Fe2O3 nanomaterials. The studied heterojunction significantly suppresses the photogenerated charge recombination rate has been proved by the photoluminescence spectroscopy (PL). The addition of methanol remarkably enhances the hydrogen evolution rate which serves as a sacrificial agent. The effect of proton sources on photocatalytic performance has been studied in detail. In the optimized system, the addition of aniline hydrochloride as a proton source has shown the highest rate of hydrogen generation (30.4 mL/h). This fundamental study along with the proposed mechanism based on several influences on the production of hydrogen from solar water splitting may open up new insights into the architectural design of photocatalysts for effective solar energy conversion.
查看更多>>摘要：? 2022 Elsevier B.V.The Eu2+ ion is extensively used as an activator due to its wide excitation band and high efficiency emission spectrum. However, most Eu2+-activated blue-emitting phosphors have low absorption efficiency in the near-ultraviolet (n-UV) region or lack the short-wavelength blue light emission (<450 nm), resulting in UV light leakage or poor color rendering. Herein, we have successfully prepared a brand-new blue phosphor NaSrScSi2O7: Eu2+ by solid-state reaction method. The Rietveld refinement of the powder diffraction data, luminescent properties, decay lifetime, quantum efficiencyand thermal quenching have been investigated in detail. Under 345 nm excitation, the NaSrScSi2O7: 0.03Eu2+phosphor manifests an asymmetric emission spectrum centered at 427 nm, and notably, shows a high absorption efficiency of 84.35%. Finally, we encapsulated two white light-emitting diodes (WLEDs) devices using as-prepared blue-emitting phosphor and three commercial phosphors. At 80 mA drive current, both packaged devices demonstrate warm white light. Meanwhile, the WLED-2 with NaSrScSi2O7: 0.03Eu2+ blue-emitting phosphor has a lower correlated color temperature of 3726 K, its spectrum complements more short-wavelength spectrum, and the special color rendering index R6 and R7 increased from 95.2, 94.5 to 98.3, 96.5, respectively, compared with WLED-1 without present phosphor. These results demonstrate that NaSrScSi2O7: Eu2+ blue-emitting phosphor is a prospective novel luminescent material for WLEDs.
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