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In order to reveal the functions of yttrium addition on damping and mechanical properties for Mg−based alloys, the damping and mechanical properties of prepared as-cast Mg−0.6Zr−xY ternary alloys with [Y] = 1.0, 2.0, 3.0, 4.0 and 5.0 mass % have been experimentally measured and theoretically explained through combining the observed microstructures with related theoretical models or mechanisms. The experimental results indicate that added [Y] in the ternary alloys has clear effect on grain refinement. Changing [Y] from 1.0 to 5.0 mass % can effectively decrease the average size of formed equiaxed α −Mg grains from 70.15 to 33.62 μm. The bulk-shaped yttrium-rich phase in α −Mg matrix is mainly composed of Mg24Y5 phase. Increasing [Y] from 1.0 to 5.0 mass % can significantly affect damping properties described by tan φ under the condition of e > e cr = 2.0 × 10−2, while no visible effect of increasing [Y] on tan φ at e e cr = 2.0 × 10−2 can be obtained. Furthermore, the influence of changing strain e from 1.0 × 10−4 to 1.0 × 10−1 on tan φ complies with dislocation pinning theory or the G−L model. Meanwhile, increasing [Y] in the ternary alloys shows the similar variation tendency for relationship between tan φ and temperature T from ambient temperature T am to 673 K (400 °C). The effect of varying temperature T from T am to 673 K (400 °C) on tan φ for the ternary alloys can be well explained by the grain boundary damping mechanism. In addition, increasing [Y] from 1.0 to 4.0 mass % can effectively promote both yield strength R p 0.2 and ultimate tensile strength R m , however further increasing [Y] from 4.0 to 5.0 mass % cannot result in an obviously increasing tendency for R p 0.2 and R m . The similar results of adding [Y] on elongation A can also be obtained with [Y] = 3.0% as a criterion. Meanwhile, the measured results of adding [Y] on R p 0.2 and R m for the ternary alloys can be well explained by the grain boundary strengthening and solid solution strengthening mechanisms. Therefore, the optimal chemical composition for as-cast Mg−Zr−Y ternary alloys with higher damping properties and greater tensile properties is recommended to be Mg−0.6Zr−4.0Y.

Magnetocaloric materials with a first order phase transition may exhibit additional thermomagnetic phase transitions in the temperature range of interest due to the second-order magnetic phase transitions of the phases. In the case of Heusler alloys exhibiting magneto-structural transformation (martensitic type), this first-order phase transition is usually accompanied by a temperature dependence of magnetization of the different magnetic structures. The temperature of the martensitic transition in this type of materials can be tuned by altering the composition, making possible a close proximity between this transition and the Curie transitions (second-order type) of the structures. This can result in a tight overlap between the two types of magnetocaloric effects, usually of different signs. In this work, the magnetocaloric response of overlapping first and second-order phase transitions of a Ni48.1Mn36.5In15.4 Heusler alloy has been deconvoluted by applying the scaling laws of the magnetocaloric effect. This deconvolution allows the prediction of the magnetocaloric response of the pure first-order phase transition, helping to gauge if it is worth synthesizing other alloys of the same family for which the Curie transition would be much more distant. The deconvoluted signal confirms that the anomalous experimental decrease of Δ S iso with increasing the field above ~ 3 T is due to the competing contribution of the overlapping second-order phase transition.

Recently, spinel ferrites have attracted much attention due to their various redox states, great electrochemical stability, and pseudocapacitive behavior. Herein, NiFe 2 O 4 /MoS 2 composite material with excellent electrochemical properties was smart-designed and successfully synthesized via a facile solution reaction and freeze-dried process for the first time. The composite combines the advantages of both MoS 2 nanosheets and NiFe 2 O 4 nanoparticles, showing enhanced capacitive performance than MoS 2 nanosheets and NiFe 2 O 4 nanoparticles and surpassed some of the previously reported materials. A maximum specific capacitance (506 F/g at 1 A/g) of NiFe 2 O 4 /MoS 2 composite was obtained, and the electrode can kept over 90.7% (at 5 A/g) of capacitance after 3000 cycles. The excellent electrochemical performance is attributed to the synergistic effect of MoS 2 nanosheets and NiFe 2 O 4 nanoparticles. Moreover, this complex material could be used in other advanced energy storage and conversion systems, such as Li-ion batteries, Li-air batteries, Na-ion hybrid capacitors, hydrogen evolution reaction catalysts, etc.

In this study, Zn–Al coatings were co-deposited on AISI 1020 steel by pack cementation. The as-prepared coatings were characterised by scanning electron microscopy, energy–dispersive X–ray spectroscopy, and X–ray diffraction. The evolution mechanism of the coating was modelled and analysed in detail. Furthermore, the corrosion resistance of the as-received coatings was investigated by a potentiodynamic polarisation test in a 3.5% NaCl solution. We observed that the relatively loose and porous structure of those coatings was a function of the Al content in the packed powders. The regions with a natural porous structure evidently increase with an increase in Al concentration. The Zn-rich layer was formed because of the dominant inward diffusion of Zn with a small diffusion of Fe in the substrate. Thus, the Zn-rich layer/substrate interface moved into the ferrous substrate. As the reaction continued, the deposition of Al dominated. The interdiffusion of Al and Zn in the Zn-rich layer and the diffusion of Fe into the Zn-rich layer towards the Al-rich layer led to the nucleation and growth of the Fe–Al phases and the consumption of the Zn-rich layer. As a consequence, the Al-rich layer/Zn-rich layer interface moved inside the Zn-rich layer. At higher deposition temperatures, when the heat was released because of the Fe–Al phase formation, the evaporation of Zn resulted in void formation in the Al-rich layer. The potentiodynamic polarisation test results show that both Zn and Zn–Al coatings significantly enhance the corrosion resistance of a ferrous substrate, but Zn–Al coatings seem to be more efficient.

The temperature variant of the First-Order Reversal Curves (TFORC) technique has been applied to study the thermal hysteresis of two magnetocaloric Heusler alloys with slightly different compositions that are close to the stoichiometry Ni50Mn34In16. The similarity of the compositions causes the samples to have similar Curie temperature but different martensitic transition temperature and thermal hysteresis, leading to different features when analyzing the TFORC distributions due to the different relative distance between the two transitions. The asymmetry of the martensitic transformation upon cooling and heating has relevant effects on the TFORC distributions. The experimental results have been compared to the predictions of a model of the transformation, which allows to separate the contributions of the magneto-structural transformation and the thermomagnetic behavior of both martensitic and austenitic phases, allowing to determine the origin of the different features of the distributions.

The magnetocaloric effect of high-entropy alloys (HEAs) due to a second-order phase transition exhibits limited response. A significant improvement is obtained in Mn22.3Fe22.2Ni22.2Ge16.65Si16.65 HEA as it exhibits a magneto-structural first-order phase transition. Its isothermal entropy change of 7.3 J kg−1K−1 (for 2.5 T) is the largest reported to date for rare earth-free HEAs. The alloy composition was found by a directed search that starts from a medium entropy alloy with the desired transformation combined with isostructural substitutions. Our findings demonstrate the existence of HEA with magneto-structural phase transition and that HEAs have promising potential as high-performance magnetocaloric materials.

In this contribution, polythiophene (PTh)/Bi4O5I2 nanocomposites are successfully synthesized through a facile route at room temperature, and evaluated as photocatalysts for the photocatalytic degradation of bisphenol a (BPA). It was discovered that the introduction of polythiophene (PTh) obviously enhanced the separation efficiency of photocharge carriers, thus promote the photocatalytic ability of Bi4O5I2. Among the as-prepared PTh/Bi4O5I2 nanocomposites, 0.5% PTh/Bi4O5I2 exhibited the optimal photocatalytic activity, the BPA degradation rate was 99.2% in 30 min. The reaction rate is about 3.7 times as high as that of pure Bi4O5I2. Moreover, the degradation products of BPA were analyzed by high performance liquid chromatography. The good stability of the composite was discovered by cyclic experiments. Finally, a possible photocatalytic mechanism was proposed.

The magnetocaloric effect of (Fe0.71RE0.05B0.24)96Nb4 (RE = Tb, Ho and Tm) bulk metallic glasses (BMGs) of diameters up to 6.5 mm were attained by 4.8 at.% RE alloying. The Curie temperature (TC) of Tm doped alloy, being the highest among these alloys, deviates from typical relationship between TC and de Gennes factor. Its unique electronic structure has been suggested to attribute to the observed trend. Furthermore, Tm doped alloy presents the largest peak magnetic entropy change ( | Δ S M pk | ) of 1.21 J kg−1 K−1 for an applied field of 1.5 T, which compares favorably with those of other Nanoperm-type alloys. The phenomenological universal curve for ΔSM demonstrates that alloys exhibit similar critical exponents at TC. This family of heavy RE doped Fe-based BMGs is potential candidate used as bulk magnetic refrigerants with the final required shapes.

NiS/MoS2 composite nanosheets were designed and prepared via facile ion-exchange, freeze-drying, and Ostwald ripening processes. MoS2 nanosheets served as backbones to absorb Ni2+ ions and form NiS nanosheets. The electrode based on the NiS/MoS2 composite nanosheets exhibited an ultrahigh specific capacity of 343.5 mA h g−1 at 9 A g−1, which was superior to that of as-prepared MoS2 nanosheets (125.8 mA h g−1) and Ni(OH)2 nanosheets (148.9 mA h g−1). In addition, NiS/MoS2 composite nanosheets presented an enhanced rate performance and good life cycle due to their hierarchical structure, high surface area with numerous active sites, and synergistic performance. A NiS/MoS2//AC asymmetric supercapacitor device operated in a large potential window (0–1.5 V) delivered a high capacitance of 48.4 F g−1 at 0.1 A g−1, an excellent energy density of 15.1 Wh kg−1 and a very high power density of 2.25 kW kg−1. This smart in situ construction process opens a new route to synthesize binary metal sulfides for high-performance energy storage devices.

The magnetocaloric effect of Fe80−xB12Cr8Gdx (x = 1, 2, 3, 5, 8, 10, 11) amorphous alloys was studied. Gd addition increases the thermal stability of the alloy and allows tuning the Curie temperature (TC). A linear relationship between the magnetic entropy change and the magnetic moment of the alloy was observed. The experimental values of magnetic field dependence of the magnetic entropy change were consistent with a phenomenological universal curve. The maximum magnetic entropy change, for x = 1, was ∼33% larger than Fe80B12Cr8, the refrigerant capacity (RC )i s∼29% larger than Gd5Si2Ge1.9Fe0.1 and within 10% of Fe82.5Zr7B4Co2.75Ni2.75Cu1 which is the best Fe-based amorphous MCM to date. The tunable TC can be used to increase RC and the temperature span of layered multi-composition magnetocaloric regenerators.

The fibers of AlN were synthesized by carbothermal reduction and nitridation of precursor fibers obtained by electrospinning. XRD result indicated that the wurtzite AlN phase had been successfully synthesized in fibers. The SEM and TEM analysis indicated that the hollow fibers with an out-diameter of about 500 nm and a wall thickness of about 100 nm were obtained and the crystal in fibers was hexagonal after calcination. The fibers were further characterized by TG–DTA, FT-IR and UV–vis absorption spectra. The formation mechanism of hollow structure was proposed based on our understanding and characterizations.