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Lightweight and easily available foams used for microwave absorption are hotspots for preventing electromagnetic (EM) pollution. In this paper, we focused on a novel kind of Ni-based foam that modified by MnO 2 nanosheets (denote as Ni@MnO 2 NS foam) was synthesized by a facile hydrothermal reaction, then analyzed by XRD, XPS and SEM characterization techniques. The Ni@MnO 2 NS foam possess excellent microwave absorption performance (MAP). In details, the superb reflection loss (RL) was up to −37.55 dB with the coating thickness of 3.6 mm and ultra-wide effective absorption (RL < −10 dB), suggesting 90% EM wave were attenuated, which could reach 11.2 GHz (from 6.8 GHz to 18 GHz). Meanwhile, the EM wave attenuation mechanism was discussed and it was proposed that the prominent MAP could be responsible for magnetic loss (natural resonance of Ni frameworks) and dielectric loss (interface polarization and dipole polarization). Ni@MnO 2 NS foam is a multifunction material that not only can be used in controlling EM pollution but also has potential application in other fields. • A novel Ni@MnO 2 NS foam was successfully synthesized. • The maximum reflection loss value is −37.55 dB. • The bandwidth with effective attenuation is up to 11.2 GHz. • It is a versatile material: abatement EM pollution and other filed. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2 ), as a significant microwave absorption materials, has been widely reported. However, it is unclear and insufficient about its microwave absorption mechanism. In this work, a series of MoS 2 -based materials with different morphology, including MoS 2 nanosheets (MoS 2 -NS), hierarchical MoS 2 (H-MoS 2 ) microspheres, hollow hierarchical MoS 2 (HH-MoS 2 ) microspheres and hydrangea-like MoS 2 / C (MoS 2 / C) microspheres, were synthesized via hydrothermal reaction. More importantly, the microwave absorption mechanism and the dielectric properties as well as microwave absorption performance (MAP) were systemically studied. The results indicated that MoS 2 / C exhibited eminent dielectric properties and MAP, which resulted from the unique structure and component. The minimum reflection loss (RL) value of MoS 2 / C microspheres/wax with 30 wt% loading is −44.67 dB at the thickness of 1.4 mm, and the corresponding bandwidth with effective attenuation (RL < -10 dB) is up to 3.32 GHz (11.7–15.02 GHz). [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) network structure nanomaterials (NMs) show excellent catalytic performance due to the larger active surface area. A glucose-directed, surfactant-free and one-step direct chemical co-reduction method for synthesis of Pt-Cu alloy nanowires (NWs) under room temperature was demonstrated in present paper. The Pt-Cu NWs were obtained through the co-reduced of CuCl 2 and H 2 PtCl 6 by sodium borohydride in the presence of glucose, the glucose in which not only acted as one-dimensional (1D) growth-directing agent, also as the stabilizing agent. The average diameter of NWs was about 3.1 nm and NWs showed typical face-centered-cubic (fcc) alloy crystal structure. The influence of Pt/Cu ions ratios in precursor solution on the bimetallic composition of NWs had been studied, and NWs displayed the feature of composition-tuning. The electro-catalytic activity of Pt-Cu alloy NWs for ethylene glycol oxidation reaction (EGOR) in alkaline medium was strongly related on their compositions. The Pt 31 Cu 69 NWs exhibited about 1.8 times higher than that of commercial Pt/C and higher durability. The enhanced catalytic performance of Pt-Cu alloy NWs was mainly attributed to their unique 3D network structure and the synergetic effects between Pt and Cu. [ABSTRACT FROM AUTHOR]

• The densification mechanism of Ti/β-Ti LMCs is sensitive to sintering temperature. • A sintering temperature above 800 ℃ is appropriate to fabricate a densified LMCs. • The α + β dual-phase structure is predominant in the interface layer. • α′ phase and ω phase at the interface enhances the microhardness. Ti/β-Ti laminated composite, which exhibits an exceptional combination of the good ductility of pure Ti and the high strength of the β-Ti alloy, has been extensively applied for biomedical applications. Here, we investigated the densification behavior of the pure Ti layer, β-Ti layer (Ti-15Mo layer), and laminated composite during the fabrication by spark plasma sintering at various sintering temperatures. The experimental results demonstrated that the majority of pores close to sintering necks could be eliminated by sintering at a temperature above 850 ℃, and both the Ti layers and Ti-15Mo layers achieved full densification. When the sintering temperature is below 700 ℃, the sintering is probably achieved by a mechanism of dislocation-climb at low compress stress and by a grain boundary sliding at high compress stress. However, the sintering was likely progressed by the dislocation-climb at 750–800 ℃ and the grain boundary sliding above 850 ℃, respectively. Besides, the influence of sintering temperature on the interfacial characteristics was investigated. The thickness of the interfacial layer was increased from 3 µm to 30 µm with the increase of sintering temperature. An α + β dual-phase structure is formed in the interface layer. The formation of α′ phase and ω phase at the interface of the composite at 1000 ℃ increased the microhardness of the interface, which is harder than the pure Ti and Ti-15Mo alloy. [ABSTRACT FROM AUTHOR]

Abstract: This article reports a solvothermal method to fabricate sub-micrometer hematite α-Fe2O3 hollow sphere, and Fe3O4 is obtained with further carbothermal reduction process. The key trick of the solvothermal method is to use crystal water of the raw material Fe(NO3)3·9H2O as the water phase in the water/oil “micro-reactor” system. Interestingly, one hole is found on the surface of almost each α-Fe2O3/Fe3O4 hollow sphere. The obtained material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmer–Teller analysis, elemental analysis and its electrochemical properties are also studied. This Fe3O4 te material shows a high reversible capacity of 917.3mAhg−1 at 90mAg−1, 849.3mAhg−1 at 900mAg−1, and can be employed as excellent anode material for high energy-density lithium ion battery. [Copyright &y& Elsevier]

In the present study, pre-deformation was applied to a metastable β titanium alloy (Ti-36Nb-2Ta-3Zr-0.35O) with the hope of improving its overall mechanical properties. The microstructural evolution and mechanical properties of the as-rolled alloys with different thickness reductions (from 4% to 35%) were characterized and analyzed. The results show that increasing the amount of pre-deformation can increase the strength (yield strength and tensile strength) of the Ti-36Nb-2Ta-3Zr-0.35O alloy without (4%–15% pre-deformation) or with only minor (23%–35% pre-deformation) sacrifice of ductility. Due to the increase of pre-deformation reduction, the β phase stability increases, leading to the twinning activities and the evolution of twinning system, which contribute to the strain hardening and the good ductility of the alloy pre-deformed by 9% and 15%. [ABSTRACT FROM AUTHOR]

Abstract Recently, high-entropy alloys (HEAs) reinforced with ceramic particles have attracted increasing attentions due to their excellent hardness, strength and wear resistance. In this study, AlCoCrFeNi-xNbC high-entropy alloy (HEA) coatings (x = 10, 20, 30 wt%) were prepared by laser cladding. The phase constituents, microstructure and mechanical properties of the HEAs were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), transmission electron microscope (TEM), microhardness and wear resistance tests. Due to the high entropy effect, the AlCoCrFeNi HEAs composites comprise only simple BCC and FCC structure phases. The addition of NbC particles results in a decrease in the fraction of the FCC phase. NbC particles are mainly distributed at the grain boundary in the HEAs with the addition of NbC. NbC particles have an advantage on the inhibition of HEA grain growth due to a strong pinning effect. The microhardness and the wear resistance of HEA composite improved significantly with the addition of NbC particles. A good comprehensive mechanical properties was obtained at the HEA with the addition of 20 wt% NbC particles. For the 20 wt% NbC-adding HEA, the average Vickers hardness is 525 HV, the average friction coefficient value is 1.023 and the mass loss is 1.05 mg. Highlights • AlCoCrFeNi-xNbC high-entropy alloys are prepared and researched. • The addition of NbC particles restrains the formation of FCC phase. • The addition of NbC particles plays a role of grain refinement. • The addition of NbC particles increases the mechanical properties of the alloys. [ABSTRACT FROM AUTHOR]

Long-term exposure of structural materials to extreme hydrogen-enriched environments will lead to hydrogen embrittlement, and thus search and design of new alloys with economic and safety benefits against hydrogen embrittlement have become a top priority for the development of many engineering fields. In this work, the hydrogen embrittlement behavior of a new cobalt-free high-entropy alloy (HEA) Fe 27 Ni 28 Mn 27 Cr 18 was systematically studied and compared with a typical quaternary HEA Fe 25 Co 25 Cr 25 Ni 25. Numerous vacancies are produced in the process of electrochemical deuterium charging and the corresponding concentration is related with the solubility of deuterium atoms. Fe 27 Ni 28 Mn 27 Cr 18 has much higher concentrations of deuterium and vacancies than Fe 25 Co 25 Cr 25 Ni 25 , which is attributed to the Mn induced severe lattice distortion and results in different variations of mechanical properties. The ultimate tensile strength (UTS) of Fe 27 Ni 28 Mn 27 Cr 18 increases from 353.73 MPa to 589.50 MPa after electrochemical hydrogen charging while the elongation still remains at 74.73%, and its deformation mechanism is dominated by dislocation proliferation. In contrast, the UTS of hydrogen charged Fe 25 Co 25 Cr 25 Ni 25 decreases from 552.79 MPa to 501.53 MPa and the corresponding elongation also decreases from 74.65% to 67.24%, and the plastic deformation mechanism is dominated by twinning. This work demonstrates an economic cobalt-free HEA with great resistance to hydrogen embrittlement, which would enhance the applications of HEAs in hydrogen-enriched environments. • The severe lattice distortion in Fe 27 Ni 28 Mn 27 Cr 18 promotes the dissolution of deuterium atoms. • Deuterium charging leads to a decrease in the plasticity of the sample and an increase in the yield strength. • Fe 27 Ni 28 Mn 27 Cr 18 alloy has high plasticity and low hydrogen embrittlement susceptibility. [ABSTRACT FROM AUTHOR]

Cerium dioxide (CeO 2) semiconductor has received wide attention in the field of energy and environment due to its excellent oxygen storage capacity and abundant oxygen vacancies (OVs). Previous research demonstrated that the morphology and structure of the crystal had great influence on the physicochemical properties of the material. Herein, CeO 2 nanomaterials with different morphologies were prepared via a facile hydrothermal and template method. Systematic material characterizations suggested that the synthetic CeO 2 has different morphologies with CeO 2 nanorods (NRs), nanocubes (NCs), nanosheets (NSs), hollow spheres (HSs), and mesoporous CeO 2 (m-CeO 2), respectively. The visible-light-induced degradation performance of CeO 2 with different morphologies was investigated in aqueous solution using the antibiotic tetracycline (TC) as a model pollutant. The experimental results exhibited that the CeO 2 NRs possessed the best adsorption capacity and photocatalytic activity and more than 89.35% TC could be removed within 90 min. Combined with the XPS characterization results implied that the concentrations of Ce3+ and OVs on the surface of CeO 2 with different morphologies were discrepancy, and the improved photocatalytic performance of CeO 2 NRs was mainly due to the higher concentration of Ce3+ and OVs on the catalyst surface. These results confirmed that the regulation of the morphology of CeO 2 could effectively enhance its photocatalytic activity. Furthermore, the results of active species trapping experiments proved that the super oxide anion (•O 2 -) radical and hole (h+) played dominant roles in the degradation of TC. [Display omitted] • In all morphologies, CeO 2 NRs exhibited a satisfactory TC degradation performance under visible light irradiation. • During photocatalysis, Ce3+ and OVs are essential for the photocatalytic properties of CeO 2. • Notably, adsorption plays the same important role as photocatalysis in TC removal. [ABSTRACT FROM AUTHOR]

• FeCoCrNiMoSi x (x = 0.5, 1.0, 1.5) HEAs were fabricated by SPS under 1150 °C. • Hardness of FeCoCrNiMoSi 1.5 reached 1186 HV. • High corrosion potential of Si makes FeCoCrNiMoSi 1.5 exhibits great corrosion resistance. • The oxidation properties FeCoCrNiMoSi 0.5 were greater than that of other FeCoCrNiMo HEAs. • Different properties can be obtained through controlling Si content. FeCoCrNiMoSi x (x = 0.5, 1.0, 1.5) high-entropy alloys (HEAs) were successfully fabricated by spark plasma sintering (SPS). The microstructure, tribological properties, oxidation behaviors and corrosion resistance of the HEAs were systematically investigated. The experimental results showed that the microstructure mainly consisted of Fe-rich face-centered-cubic (FCC) phase, Mo-rich FCC phase solid solution and various Si-rich intermetallics, where the elevated Si content coarsened the primary Mo-rich phase into dendritic eventually. These Mo-rich dendrites possessed strong covalent-dominant atomic bonds that enhanced the microhardness (from 725 to 1186 HV) and wear resistance. The FeCoCrNiMoSi 0.5 HEA exhibited an outstanding combination of relatively high wear resistance and the strongest oxidation resistance under 800 °C among the three alloy compositions. The corrosion resistance of HEAs showed an increasing trend with the elevated Si content, and FeCoCrNiMoSi 1.5 presented the best performance. [ABSTRACT FROM AUTHOR]

Abstract: The high-temperature cycling stability at a high cutoff voltage of LiNi0.5Co0.2Mn0.3O2 was improved by TiO2 coating. The mechanism of enhancement was elucidated by electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analyses. TiO2 coating formed a uniform layer on the surface of LiNi0.5Co0.2Mn0.3O2 particles without changing the crystal structure. Electrochemical tests indicated that TiO2 coating can improve the lithium ion intercalation stability at 328K and at a high cutoff voltage of 4.4V. The 1.0% TiO2-coated LiNi0.5Co0.2Mn0.3O2 discharged 149.2mAhg−1 after 100 cycles at 0.5C, and maintained 92.1% of the initial discharge capacity. By contrast, the bare sample discharged only 87.7mAhg−1 with 48.2% capacity retention. ICP-AES results proved that the TiO2 coating layer can reduce the dissolution of transition metal ions from LiNi0.5Co0.2Mn0.3O2. EIS and XPS confirmed that the improved cycling stability can be attributed to the suppression of the reaction between cathode and electrolyte in lithium-ion batteries. [Copyright &y& Elsevier]