Journal of Alloys and Compounds
ISSN / EISSN : 0925-8388 / 1873-4669
Published by: Elsevier BV (10.1016)
Total articles ≅ 63,396
Latest articles in this journal
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162084
The challenge of enhancing the high-temperature oxidation resistance of titanium alloys is hereby addressed by the addition of TiB whiskers and nano-silicide. The cyclic oxidation tests results showed that the weight gains of the composites with reinforcements were less than that of titanium alloy, and the oxidation film of the silicide/composite only appears little peeling after heating at 1123K for 100h. The grains were refined by the introduction of reinforcements, thus the high-density grain boundary can be also used as the nucleation site of oxidation products to refine the oxide grains and effectively inhibit the internal diffusion process of oxygen. Additionally, nano-silicide distribution at grain boundaries cause short-circuit diffusion, resulting in preferential oxidation at grain boundaries thus forming a network structure, which effectively hinders the inward diffusion of oxygen and better inhibits the growth of oxidation scale. DFT calculation shows that TiBw and nano silicide reinforcement with weak oxygen binding ability can reduce the adsorbed oxygen atoms and prevent the further oxidation growth of the matrix.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162073
The B2 structure based MIL composites was fabricated by a two-step processing: the stacked Al and Fe foils were firstly hot pressed under eutectic reaction to form the Al-rich intermetallic phase(Fe2Al5) layer by consuming all the Al foils. And then, for forming the Fe-rich intermetallic phase (FeAl with B2 structure), three kinds of experiments were carried out to transfer the Al-rich phase layer to B2 structure: annealing at eutectic temperature for a long time; hot pressing or Spark Plasma Sintering (SPS) at higher temperature (1000℃). The EDS, EBSD, XRD, micro-hardness tests and quasi-static compression are applied to study microstructure evolution, phase transformation and identification during fabricating the B2 structure based MIL composites. Mechanical properties of the B2 structure based MIL composites has proved the reduction of the stress concentration on the interface.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162082
We studied the effect of Mn on the structure and properties of Cd3-xMnxAs2 crystals with x = 0-0.24, synthesized by direct fusion of high-purity elements. Obtained X-ray diffraction patters suggest that the incorporation of Mn promotes a structural phase transition from primary α-Cd3As2 (x = 0) phase to the α''– Cd3As2 (x = 0.24) phase, while at intermediate compositions both phases can coexist. In addition, the increase of Mn content results in the decrease of lattice cell parameters, which effectively saturates for x > 0.13. Microstructural, calorimetric and magnetometry studies suggest that at high Mn content (x = 0.24) secondary MnAs phase appears. Using obtained results, we estimated the solubility limit of Mn in Cd3As2 as x ~ 0.13, which corresponds to the formation of ternary Cd3-xMnxAs2 compound where Cd atoms are partially substituted by Mn. Formation of ternary compound was also suggested by the results for Cd3As2 + MnAs composite systems, where we also observed the presence of CdAs2 phase, which is a byproduct of corresponding reaction. Additional studies suggested that the CdAs2 phase formation in composite system can be prevented if one uses the Cd3-xMnxAs2 compound instead of pure Cd3As2 as a matrix material.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162092
Temperature sensor and field emission displays (FED) are the intensive topics for Sm3+ activated red phosphor. In this study, a novel lithium nitride red phosphor Li2CaSi2N4:Sm3+ was successfully prepared by solid phase method. The photoluminescence and cathodoluminescence performances were systematically studied to explore the possibility in FED and temperature sensor applications. The results indicate that the Li2CaSi2N4:Sm3+ phosphor features intense red emission under the UV light and cathode ray excitations. The phosphor also has a long red afterglow with an afterglow time of 12.7min. Most importantly, Li2CaSi2N4:Sm3+ exhibits excellent temperature sensitivity with the relative sensitivity of 4.8% K-1 @ 473K, which is higher than other temperature sensor materials. The thermal quenching mechanism was proposed based on a configurational-coordinate model. Moreover, excellent cathode ray saturation and aging resistance were observed in Li2CaSi2N4:Sm3+. The results indicate that Li2CaSi2N4:Sm3+ is a potential temperature sensor and FED materials.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.161998
The recent electronic appliances and hybrid vehicles need a high energy density supercapacitor that can deliver a burst and a quick power supply. The high energy density supercapacitor can be obtained by designing proper electrode materials along with appropriate electrolytes. This review begins with different mechanisms of energy storage, giving a brief idea regarding how to design and develop different materials to achieve proper electrodes in the pursuit of high-energy density supercapacitor without compromising its stability. This review later focuses on the engineering of different electrode materials like conducting polymer, metal oxides, chalcogenides, carbides, nitrides, and MXenes. Lastly, the hybrid electrodes made up from composites between graphene and other novel materials were investigated. The hybrid electrodes have high chemical stability, long cycle life, good electronic properties, and efficient ionic transportation at the electrode-electrolyte interface, showing great potential for commercial usage.
Journal of Alloys and Compounds, Volume 891; https://doi.org/10.1016/j.jallcom.2021.162040
In dye-sensitized solar cells (DSSCs), TiO2 has long been a popular electron transport material for carrying photo-generated electrons from the dye to the outer circuit. However, increasing the electrical conductivity of TiO2 while preserving its properties is one of the most significant challenges for increasing DSSC efficiency. Here, cobalt-reduced graphene oxide co-doped TiO2 nanoparticles were synthesized by a modified sol-gel procfess that together controlled the particle size as well as narrowed bandgap of nanoparticles as determined by XRD and UV-Vis absorption measurements. The SEM and TEM were used to perform in-depth morphological characterization of the newly synthesized nanocomposites while J-V (current-voltage) curves, EIS Nyquist curves, and incident photon to current conversion efficiency (IPCE) spectra were used to examine the photovoltaic parameters. Enhanced short circuit current density (Jsc 12.83 mA cm−2), open-circuit voltage (Voc 0.618 V) and overall power conversion efficiency (PCE, η = 5.24%) of DSSC was obtained with Co/rGO co-doped TiO2 based photoanode in comparison to bare TiO2 (η = 3.71%), cobalt doped TiO2 (η = 4.09%) and rGO doped TiO2 (η = 4.43%) based DSSCs. Huge improvement in efficiency, 41% higher PEC in Co/rGO co-doped TiO2, was attributed to better utilization of visible radiations, greater dye adsorption and enhancement in charge transfer properties by suppressing the electron transport resistances. The incorporation of rGO improved electron transfer, which compensated for recombination losses, thereby increasing the DSSC's Jsc. The synergetic role of rGO and transition metal helped in keeping the structure intact in the nano-assembly that enhance the photo-generated carriers.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162045
The application of the high-entropy concept has generated many interesting results for both alloys and ceramics. However, there are very few reports on high entropy thermoelectric materials. In this work, a single phase high-entropy half-Heusler compound MFe1-xCoxSb with 6 equimolar elements (Ti, Zr, Hf, V, Nb and Ta) on the M site was successfully synthesised by a simple method of mechanical alloying, and the single phase was maintained after densification by spark plasma sintering. The multi-elements are homogenously distributed in the samples. The samples are stable and there is no phase separation after annealing at 1073K in argon for 72h, which could be attributed to their high configurational entropy. Due to the phonon scattering introduced by multi-elements, the lattice thermal conductivity is largely supressed with a lowest value of ~ 1.8 - 1.5 Wm-1K-1 (300K - 923K) for MCoSb. By adjusting the Fe/Co ratio, the samples can show both n-type and p-type semiconductor behaviour. Maximum zT values of 0.3 and 0.25 are achieved for n-type MCoSb and p-type MFe0.6Co0.4Sb, respectively. The results suggest that the high-entropy concept is a promising strategy to extend the composition range and tune the thermoelectric properties for half-Heusler materials, which could potentially be applied in other thermoelectric materials.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162088
In which ferroelectric polarization can be locally controlled have potential for high-density information storage applications. Herein, we investigated the ferroelectric polarization switching characteristics of epitaxial BaTiO3/PbTiO3 (BTO/PTO) multilayer thin films by using piezoresponse force microscopy. Pulsed laser deposition was used to form an epitaxial BTO layer on an epitaxial ferroelectric PTO single thin film. This epitaxial BTO/PTO multilayer thin film exhibited an imprint phenomenon, in which the internal electric field was asymmetrically induced and the ferroelectric hysteresis loop was shifted. Owing to this imprint phenomenon, a large difference occurred between the two coercive electric fields of the ferroelectric hysteresis loop. Because the coercive electric field was reduced in one direction, a relatively small switching voltage was required to form ferroelectric polarization nanobits in a local region and the size of the switched nanobits was minimized. This behavior can be utilized as the basis for developing high-density ferroelectric-based storage media.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162093
In this paper, we outline the construction of symmetric supercapacitors comprised of reduced graphene oxide (rGO) and hydrophobic ionic liquid (IL) (1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (EMIMTFSI) acting as physical spacer and electrolyte between rGO plates. To increase the porosity and interlayer spacing between the graphene plates, different solvents are analyzed by Hansen solubility parameters’ approach (HSP). Accordingly, the solubility performances of two solvents, namely Tween 80 and N, N-dimethylformamide (DMF), coupled with rGO and IL, are deemed to offer the most beneficial results, and they are the solvents used in this study to develop rGO/Tween 80/IL and rGO/DMF/IL electrodes. The comparison of the electrodes’ performances shows that the consumption of 80 weight percent IL would deliver the optimum electrochemical performance and capacitance results. At room temperature, the prepared rGO/Tween 80/IL80% and rGO/DMF/IL80% deliver capacitances of 375 and 213F/g, respectively. The maximum energy density of rGO/Tween 80/IL electrode is 187.5Wh/kg at a power density of 1125W/kg, while for the rGO/DMF/IL electrode the maximum energy density reaches 106.5Wh/kg at a power density as high as 639W/Kg. The supercapacitors prepared based on rGO/Tween 80/IL80% and rGO/DMF/IL80% electrodes show capacitance retention of 90% and 84% after 10,000 charge-discharge cycles, respectively. This design approach eliminates the need for the prevalant stand-alone type of electrolyte in supercapacitors, and instead, the electrolyte is incorporated as a component of electrode’s structure.
Journal of Alloys and Compounds; https://doi.org/10.1016/j.jallcom.2021.162075
In this paper, a sphere-like MoS2 and porous TiO2 composite film was prepared on Ti foil by plasma electrolytic oxidation and magnetron sputtering methods. The prepared film was assembled as a binder-free anode in the lithium-ion battery and a Li foil served as the counter electrode. The specific capacity and cycling stability of the electrode were evaluated, together with the cyclic voltammograms and electrochemical impedance spectra. The TiO2/MoS2 composite film anode combined the advantages of TiO2 with high structural stability and MoS2 with high theoretical capacity. The electrochemical performance exhibited a specific capacity above 400 mAh g-1 at the current density of 100µAcm-2, which was much higher than that of the TiO2 anode. Besides, after cycling under a high current density of 1000 μA cm-2, the capacity came back to 91% of the initial capacity, showing a good rate capability. The porous TiO2 prepared by plasma electrolytic oxidation can provide a significant number of internal channels for the Li+ diffusion, resulting in a high porosity of 33.5% - 41.6%, and a high Li+ diffusion coefficient of 3.12×10-14 - 6.67×10-14 cm2/s, which was beneficial for the enhanced electrochemical performance.