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In this manuscript, an introduced ionic liquids-ethylene glycol-KOH electrolyte system is proposed. Theoretical calculations and experiments show that ionic liquids with stronger hydrophobicity provide better corrosion inhibition for their spontaneous adsorption behavior and water molecule segregation. In this process, the imidazole ring cations play a major role. The electrolyte system reconstructs the Al/electrolyte interface with poor H 2 O, thus has lower self-corrosion rate for [BMIM]PF 6 and contributes to the uniform dissolution of Al anode. Additionally, discharge performance of the full-cell feature same trend, endowing an outstanding capacity of 1971 mAh g−1 and anode utilization of 66.2% in alkaline [BMIM]PF 6 -ethylene glycol electrolyte. In terms of maintaining the activity of the Al-6061 anode whilst keeping low corrosion rate level, the proposed electrolyte system seems to be potential alternative. [Display omitted] • An aluminum-ionic liquid-alkaline electrolyte interface is constructed for Al-air batteries. • Al-molecular H 2 O-poor interface significantly suppresses the self-corrosion via the initiative adsorption of ionic liquid. • Imidazole ring of studied ionic liquids plays a dominant role in the adsorption behavior. [ABSTRACT FROM AUTHOR]

Excess impurity Fe will form various intermetallic compounds in Al-based alloys, such as α-Al 8 Fe 2 Si and β-Al 5 FeSi, which greatly reduce the elongation of alloys. Therefore, Fe removal is a promising approach for high performance Al-based alloy. In this paper, we propose an effective method for the Fe removal from Al-7Si alloys by adding Sn. Based on the thermodynamic calculations, the element Sn was selected for Fe removal. The microstructure of Fe-rich compounds and Fe content in alloy were compared by optical microscope (OM), scanning electron microscopy (SEM) and inductively coupled plasma generation spectrometer (ICP). It was observed that the reduction of Fe content in Sn can reach 33.8%, comparable to the level of adding B. More Fe-rich compounds deposited at the bottom after addition of Sn. However, the phase type and morphology of Fe-rich compound were unchanged. The β-Sn attached to the β-Al 9 Fe 2 Si 2 which was determined by transmission electron microscopy (TEM), and a coherent interface between β-Sn and β-Al 9 Fe 2 Si 2 phase was observed with the orientation of (0 0 1)[1 1 0] β-Sn ∥(2 2 0)[0 0 1] β-Al9Fe2Si2. It deduced that the attached β-Sn with larger density than alloy would lead to more deposition of β-Al 9 Fe 2 Si 2. This study provides an insight into the preparation of high-performance Al-Si alloy by removing Fe from secondary Al alloy with Sn addition. [Display omitted] • Sn is selected for iron removal based on the thermodynamic calculations. • The iron removal rate of Al-7Si-1Fe can reach 33.8% by adding Sn. • The β-Sn will attach to the surface of β-Al 9 Fe 2 Si 2 phase and settle it. [ABSTRACT FROM AUTHOR]

In this work, we synthesized a series of Gd 2 SrAl 2 O 7 : Mn4+/Bi3+/Na+ phosphors by sol-gel method. The experimental results show that there is energy transfer from Bi3+ to Mn4+. By introducing Bi3+ and Na+ ions into the host, emission intensity of the optimal phosphor can be increased to 2.5 times that of Gd 2 SrAl 2 O 7 : Mn4+ and its internal quantum yield is as high as 79.9%. Furthermore, the optimal phosphor also exhibits satisfactory luminescence thermal stability, whose PL intensity at 423 K retained 80.2% of that at room temperature and the activation energy reaches up to 0.45 eV. Mechanism of photoluminescence improvement can be attributed to efficient energy transfer, charge compensation and enhanced crystal rigidity. Packaged LED device exhibits dazzle far red light and its PL spectrum widely overlaps with the absorption band of phytochrome P FR. The performance indexes support the prospective application of the optimal phosphor in plant growth lighting. • The novel layered double-perovskite phosphor Gd 2 SrAl 2 O 7 :Mn4+, Bi3+, Na+ has been prepared by sol-gel method. • Gd 2 SrAl 2 O 7 :Mn4+, Bi3+, Na+ exhibits satisfactory luminescent thermal stability. • Mechanism of luminescent performance improvement is analyzed in detail. • Gd 2 SrAl 2 O 7 :Mn4+, Bi3+, Na+ is suitable for indoor plant growth LED lighting. [ABSTRACT FROM AUTHOR]

The effect of long-term isothermal aging of Haynes 230 super-alloy in an advanced ultra-supercritical (A-USC) power plant at 700 °C for up to 10,000 h on microstructural evolution and tensile behavior. And utilizing a combination of the scanning electron microscope (SEM), X-ray diffraction analysis (XRD), and transmission electron microscope (TEM). Although the grain size and grain boundary M23C6 carbides did not change significantly, the dissolution of intercrystallite primary M 6 C carbides and the precipitation of intracrystalline secondary lamellar M 6 C carbides were observed at 2000 h to 10,000 h. According to the SEM and TEM results, it is shown that the dissolution of primary M 6 C carbides makes the W, Mo, and Cr in the γ matrix increase, while the precipitation process of secondary M 6 C carbides is M+ 6 C→M 6 C. To reduce the interfacial energy of the γ matrix, secondary M 6 C carbides are precipitated in the crystal under long-term aging at 700 °C, with a gradual increase in time content. the best tensile and yield strengths at 750 °C occur after 4000 h of aging, with microscopic voids forming mainly around the granular M 6 C carbides in the crystal, but the solid solution strengthening effect of the matrix provides the strength. The worst strength and elongation occur after 10000 h aging, when the dissolution of granular M 6 C and secondary precipitation of M 6 C carbides are most abundant, interfacial cavity formation of granular M 6 C carbides and brittle fracture of M 6 C carbide particles, and the growth of non-co-grained secondary M 6 C carbides with the matrix allow more microscopic cavities to appear during high-temperature tension, reducing the strength of Haynes 230 and plasticity. • Phase precipitation behavior of Haynes 230 was investigated during long-term aging at 700 ℃. • Precipitation processes of secondary lamellar-like M 6 C carbide were clarified. • Dissolution of primary granular M 6 C carbides was discussed. • Variation in mechanical properties is divided into several stages. • The relationship between precipitation processes and mechanical properties was established. [ABSTRACT FROM AUTHOR]

Herein, to improve the electrical characteristics, ZnO linear resistors mixed with MgO, TiO 2 , Al 2 O 3 , and various concentrations of Sc 2 O 3 (with 0, 0.35, 0.7, and 1.05 wt %) were obtained using the conventional solid-state sintering technique, while the influences of Sc 2 O 3 doping on the micro-morphology and electrical characteristics was investigated in detail. The crystalline phases and microstructure were investigated by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The dielectric properties and electrical characteristics were evaluated using a precision inductance-capacitance-resistance meter and a high-voltage source meter. Results from SEM micrographs, XRD patterns, and EDS mappings illustrated that the doping of Sc 2 O 3 hinders the growth of ZnO grains. Electric field-current density and resistivity-frequency measurements illustrated that the doping of Sc 2 O 3 improves the linear performance of ZnO linear resistors and increases its grain resistivity and grain boundary resistivity. With Sc 2 O 3 doping, the dielectric properties of the samples are significantly affected, while the resistance-temperature features reveal the negative temperature constant function. By appropriate Sc 2 O 3 doping, the ZnO linear resistors exhibited excellent performance with grain boundary barrier height φ b of 0.0106 eV, nonlinear coefficient α of 1.03, and resistance temperature constant α T of −2.88 × 10−3. It is beneficial to investigate the influence of Sc 2 O 3 doping on the micro-morphology and electrical performances in detail for the preparation of zinc oxide linear resistors with superior performance. • With Sc 2 O 3 doping, the ZnO grain size d is decreasing. • Sc 2 O 3 as a donor additive, enhances the linear characteristics of ZnO linear resistors. • With Sc 2 O 3 doping, the ε r and tanδ of the ZnO linear resistors decrease. [ABSTRACT FROM AUTHOR]

Ti-15Mo alloys have been widely used as biomedical materials. However, problems such as stress shielding and peri-implant infection occur when Ti-15Mo alloys are implanted in vivo. In this study, the function-structure-integrated Ti-15Mo- x Cu (x = 3, 7, 11 and 15 wt%) alloys were prepared by powder metallurgy using Ti, Mo and Cu powders as raw materials. The results revealed that the Ti-15Mo- x Cu alloys were mainly composed of β -Ti, α-Ti and Ti 2 Cu phases. The Ti 2 Cu phase combined with α -Ti formed a layer phase at the grain boundary. The strength of Ti-15Mo- x Cu alloys decreased with Cu content increasing. When the Cu content was 11 wt%, the Ti-Mo-Cu alloy exhibited the higher compressive strength of 318.8 MPa and the lowest elastic modulus of 5.2 GPa. Simultaneously, the concentration of Cu ion release was proportional to the Cu content, which further affected the antibacterial activity. A high concentration of Cu ions was released from the alloys, and then became stable. Antibacterial rates of S. aureus and E. coli beyond 95% with good cytocompatibility can be obtained for the Ti-15Mo-11Cu alloy. This research revealed that the Ti-15Mo-11Cu alloy has excellent mechanical compatibility and antibacterial properties, which could satisfy the requirement for implant of human cortical bones. [Display omitted] • The function-structure-integrate method was used to design Ti-Mo-Cu alloy prepared by powder metallurgy. • The crack propagation mechanism of Ti-Mo-Cu alloy was revealed. • The alloy could possess good mechanical compatibility and cytocompatibility. • The addition of 11-15 wt. %Cu improved antibacterial properties of the Ti-Mo alloy against E.coli and S. aureus. [ABSTRACT FROM AUTHOR]

The design of high-performance NO 2 sensors that work at room-temperature is particularly important for expanding the range of NO 2 detection applications. To improve the detection sensitivity of ZnO to NO 2 at room-temperature, Cr-modified ZnO@ graphene-like UC (ultrahigh-surface-area carbon matrix) composite sensors were prepared by a two-step wet-impregnation strategy. Transition metal Cr was used to modify ZnO to improve its catalytic properties. The modified ZnO was composited with the nanopores of UC to improve the specific surface area of the material and prevent the agglomeration of ZnO. The sensor exhibits superior NO 2 sensing performance at room-temperature, and the response value reaches 2.7 at a NO 2 concentration of 1 ppm. Density functional theory (DFT) was used to calculate the adsorption model of nitrogen dioxide on the sensor surface, and the mechanism of enhanced sensing was revealed. The enhanced NO 2 gas sensing performance is attributable to Cr modification decreasing the band gap width and enhancing the electron transition ability. Moreover, an impurity energy level is introduced after Cr modification, causing the formation of new chemical bonds, and the orbital hybridization of O, Cr, and ZnO results in the redistribution of electrons and enhanced electron transfer. [Display omitted] • Cr-ZnO@ graphene-like UC composites synthesized to fabricate room-temperature efficient NO 2 sensors. • Cr and ZnO cooperate to form a series charge pathway that enhanced the NO 2 response value. • Conversion of materials from n-type to p-type with the increase of UC content and the sensing performance is improved. • DFT calculation reveals Cr modification decreases the band gap width and enhances the electron transition ability. [ABSTRACT FROM AUTHOR]

Since seawater is one of the most abundant resources on earth, seawater electrolysis is becoming increasingly attractive for clean energy/hydrogen production. Although significant progress has been made recently, it is still challenging to obtain bifunctional electrocatalysts with high catalytic activity and durability suitable for seawater electrolysis because of the scarcity of precious metals and inadequate state-of-the-art materials for the overall reaction. The development of high-performance bifunctional electrocatalysts is crucial to the commercialization of overall seawater electrolysis and in this review, the mechanism and challenges of seawater electrolysis are introduced. Optimization strategies for different types of non-noble-metal-based electrocatalysts including structural regulation, interface regulation, doping regulation, in situ assembly, alloying, and amorphization are summarized to elucidate the relationship among composition, structure, and properties. Finally, the challenge and prospective for future development of non-noble-metal-based bifunctional catalysts are discussed. This paper aims at providing guidance and insights into the rational design of highly efficient catalytic materials for practical seawater splitting. [Display omitted] • Non-noble-metal-based bifunctional seawater electrocatalysts are described. • A series of non-noble-metal-based bifunctional catalysts for overall seawater splitting are summarized. • Challenges and prospective of seawater electrocatalysts are presented. [ABSTRACT FROM AUTHOR]

Composite materials based on reduced graphene oxide decorated with cuprous telluride nanoparticles (Cu 2 Te NPs@rGO) were fabricated using a facilitated two-step method. A back-contact layer was formed using a spin-coating method for cadmium telluride (CdTe) solar cells. This research is aimed to improve the photovoltaic performance of a device containing Cu 2 Te NPs@rGO/Au back contacts. Cu 2 Te NPs, as the active copper diffusion source, dope and passivate the interfaces and grain boundaries of CdTe to form the p+-layer, which can reduce the recombination centers and back-contact barrier height. Simultaneously, the reduced graphene oxide (rGO), as a buffer and carrier transport layer, prevents excessive copper diffusion during the annealing process and improves the hole collection capacity. The p-type layer formed by the rGO contact with the Au film enhances hole transport and facilitates a low-resistance contact formation, forming a quasi-ohmic contact, and increases the open-circuit voltage and short-circuit current density. Cu 2 Te NPs@rGO/Au back contacts significantly improved the photovoltaic performance (E ff : 16.5%, V oc : 830 mV, J sc : 27.13 mA/cm2, fill factor: 73.3%, area: 0.24 cm2). The composites retain properties of Cu 2 Te NPs and rGO. Their multifunctional properties reveal the potential of Cu 2 Te NPs@rGO as the back contact and broaden the application of graphene-based composites in photovoltaic devices. Additionaly, the preparation of graphene-based composites and their application as back contact is simple and convenient. • The Cu 2 Te NPs@rGO composites is synthesized by a facilitated two-step method. • The Cu 2 Te NPs@rGO composites is firstly used as the back contact for CdTe solar cells. • Cu 2 Te NPs can effectively dope the CdTe layer, and rGO/Au can reduce the barrier height. • A quasi-ohmic contact is formed by the Cu 2 Te NPs@rGO composites. • A significant enhanced performance (e.g., Eff: 16.5%, V oc : 830 mV, J sc : 27.13 mA/cm2, FF: 73.3%, area: 0.24 cm2) is achieved for CdTe solar cells. [ABSTRACT FROM AUTHOR]

Nickel can enhance the elevated temperature property of Al alloys, but blocky and aggregated Ni-rich intermetallic induced by high Ni content can seriously reduce the properties at room and elevated temperatures. Accordingly, finding ways to optimize Ni-rich intermetallic and performance at room and elevated temperatures is of great significance. In this regard, we couple travelling magnetic fields (TMF) with sequential solidification to alter the content, morphology, distribution and growth of Ni-rich intermetallic in Al-Cu-based alloys with high Ni content, further to increase the related performance. Moreover, simulations are combined with experiments to comprehensively reveal the mechanisms on these optimizations during each stage of solidification process. Current findings indicate that Ni-rich intermetallic and matrix phase α -Al are effectively refined, modified and diffusely distributed, and growing in random directions by TMF process. Hence, the performance at both room and elevated temperatures are greatly improve. Specifically, Down-TMF increases the UTS, YS, elongation and hardness at 298 K from 147.8 MPa, 90.8 MPa, 6.0 % and 75.6 kg·mm−2 without TMF to 186.7 MPa, 102.7 MPa, 10.4 % and 85.2 kg·mm−2. While, Up-TMF raises them to 179.2 MPa, 95.1 MPa, 8.5 % and 83.2 kg·mm−2. Additionally, Dwon-TMF improves the UTS, YS and elongation at 473 K from 99.0 MPa, 77.6 MPa and 17.3 % without TMF to 153.7 MPa, 86.1 MPa and 18.2 %, and from 74.7 MPa, 65.6 MPa and 18.5 % at 573 K to 84.4 MPa, 75.8 MPa and 25.7 %. While, Up-TMF promotes their elevated performance to 162.9 MPa, 88.9 MPa and 17.6 % at 473 K, and to 87.2 MPa, 77.0 MPa and 22.5 % at 573 K, respectively. Noteworthily, Down-TMF generates more overall positive effects than Up-TMF. • Travelling magnetic fields coupled with sequential solidification effectively optimizes the Ni-rich intermetallic. • TMF greatly improves mechanical performance at room and elevated temperatures for Al-Cu-based alloys with high Ni content. • Down-TMF can generate more overall positive effects to alloy castings than Up-TMF. [ABSTRACT FROM AUTHOR]

A thermally tunable multiband terahertz metamaterial absorber comprising a periodic array of closed metallic square ring resonators and four metal bars parallel to the four side of the square ring, fabricated on the low-temperature co-fired ceramic (LTCC) strontium titanate (STO) dielectric layer dielectric substrate has been proposed. The resonance frequencies of the absorber are demonstrated to be continuously tuned in the terahertz regime by increasing the temperature. It is found that in the window between 0.05 and 0.35 THz the absorber has three distinctive absorption peaks at frequencies 0.129 THz, 0.198 THz and 0.316 THz (at the room temperature), whose peaks are attained 99.3%, 99.1% and 94.6% respectively. The tunability is attributed to the temperature-dependent permittivity of the substrate and attained to 67.3% frequency tuning depth at the room temperature, when the temperature varied from 400 K to 200 K. The proposed designs ensure broadband thermally tunable terahertz devices. [ABSTRACT FROM AUTHOR]

In the past decades, a great variety of single-phase white-emitting phosphors have been developed, however most them can't satisfy us due to their low quantum efficiency and poor thermal stability. Herein, we reported a promising candidate of a white-emitting La 2 (GeO 4 )O:Bi 3+ /Eu 3+ phosphor, exhibiting an efficient energy transfer, good thermal stability and high quantum efficiency. Rietveld structure refinement of La 2 (GeO 4 )O:Bi 3+ was performed to confirm Bi 3+ occupation of La sites in La 2 (GeO 4 )O. An analysis on the red-shift of both excitation and emission spectra of La 2 (GeO 4 )O:Bi 3+ was made by combining the crystal structure and their spectroscopy. Thermal quenching temperature (T 50% ) of La 2 (GeO 4 )O:Bi 3+ was approximately 532 K which is higher than that (473 K) of the LED chips under high power current driving and La 2 (GeO 4 )O:Bi 3+ presented a spectral blue-shift as an increase in temperature. Furthermore, thermal quenching of La 2 (GeO 4 )O:Bi 3+ was explained in detail by the configurational coordinate. More importantly, single Bi 3+ doped La 2 (GeO 4 )O presented a blue-greenish broad band at 480 nm with a high quantum efficiency (48%) and excellent thermal stability (ΔE = 0.353 eV). Energy transfer from Bi 3+ to Eu 3+ in La 2 (GeO 4 )O efficiently occurred and energy transfer mechanism of Bi 3+ →Eu 3+ was demonstrated to be dipole-quadrupole interaction. By codoping Eu 3+ in La 2 (GeO 4 )O:Bi 3+ , La 2 (GeO 4 )O:Bi 3+ , Eu 3+ phosphor exhibited the blue-green and red dual emissions. Fortunately, a single-phase white-emitting phosphor La 1.94 (GeO 4 )O:0.03Bi 3+ , 0.03Eu 3+ was obtained with excellent resistance against thermal quenching and a quantum efficiency of 37%. [ABSTRACT FROM AUTHOR]

In this study, Na 3 Zr 2-x Nb 0.8x Si 2 PO 12 , Na 3 Zr 2-x Ti x Si 2 PO 12 , Na 3 Zr 2-x Y x Si 2 PO 12-0.5x , Na 3 Zr 2-x Zn x Si 2 PO 12-x ceramics with x = 0.1, 0.2, 0.3 and 0.4 were sintered to explore the influence of the valence state and the content of dopants on the conductivity of NASICON solid electrolyte. Archimedes method, X-ray diffraction, scanning electron microcopy and complex impedance spectroscopy were used to characterize the sintered samples. Results show that the dopant with +2 oxidation state cations improves the bulk conductivity mainly due to the less electrostatic interactions between Zn 2+ ions and Na + ions. The optimal doping content of Nb 5+ , Ti 4+ and Y 3+ doped NASICON ceramics is 0.1 mol and that of Zn 2+ doped NASICON ceramic is 0.2 mol for the highest ionic conductivity. Among all the doped NASICON ceramics, Na 3 Zr 1.8 Zn 0.2 Si 2 PO 11.8 ceramic displays the highest total conductivity of 1.44 × 10 −3  S/cm and bulk conductivity of 3.41 × 10 −3  S/cm at room temperature. Furthermore, doping strategy both increases the density and decreases the sintering temperature of Na 3 Zr 2 Si 2 PO 12 ceramic. [ABSTRACT FROM AUTHOR]

A novel method is developed to fabricate an Al 2 O 3 /Fe-Al composite coating on 1045 steel with excellent mechanical properties and wear resistance. Proper thermal treatment of the ball-milling Fe-Al powder is essential to achieve in-situ assembled Al 2 O 3 nanoparticles, which plays a pivotal role in the mechanical properties of the coating obtained by a subsequent laser cladding process. Systematic studies show that the in-situ grown Al 2 O 3 nanoparticles with a diameter of 50–100 nm assembling on the Fe-Al powder is fabricated by thermal treating the ball-milling Fe-Al powder at 850 °C for 2 h under 0.1 Pa vacuum atmosphere. This kind of metal feedstock is important to achieve a uniform Al 2 O 3 nanoparticles reinforced Fe 3 Al laser cladding coating, with minimum lattice misfit and high thermodynamic stability characteristics. The in-situ grown Al 2 O 3 nanoparticles with proper sizes in the laser cladding coating refine the solidified microstructure and inhibit the growth of cracks, resulting in not only the enhancement of hardness and toughness, but also a lower specific wear rate of 0.1811 × 10 −3  mm 3  N −1 •m −1 in the dry sliding test. [ABSTRACT FROM AUTHOR]

We demonstrate that the confinement effect of the NiO compound can directly enhance the electrochemical performance upon cycling. Fabricating the core-shell C-coated Ni/NiO nanofibers (e.g., Ni and NiO, nitrogen doped carbon respectively) composite electrode largely increases the capacity (1332 mAh g −1 vs 718 mA h g −1 ) and improve the long-term cycling stability. The High Angle Annular Dark Field results reveal that the doped pyridine-like nitrogen shell will divide the NiO into smaller nanoparticle during the charging and discharging process. In addition, the density functional theory calculation suggests the confined nanoscale NiO(Ni) will absorb and react with Li ions more easily. With cycling, smaller NiO/Ni nanoparticle will bring more active sites, leading additional interfacial lithiation capacity. At the same time, the confinement effect of the NiO compound further increases the capacity of the nanocomposites. [ABSTRACT FROM AUTHOR]

Laser additive manufacturing was one attractive method to rebuild the geometric features and regain a part of the mechanical properties of metallic alloys. But some adverse effects, such as tensile stress and heat-affected zone, were introduced and resulted in the low fatigue strength. Laser shock peening (LSP) is a technique to produce compressive residual stress and change microstructure. In this paper, the surface and profile residual stress distributions were presented on laser additive TC17 titanium alloy with and without LSP treatment. The tensile stress changed into compressive stress after LSP treatment. The microhardness and tensile properties of the laser additive specimens were presented and compared before and after LSP treatment. In addition, the microstructure characteristics in different regions of laser additive TC17 titanium alloy were characterized by scanning electron microscope and transmission electron microscope observations. Moreover, three kinds of specimens, namely substrate, laser additive and LSP post-laser additive, were subjected to fatigue tests. The fatigue strength of laser-additive specimens reduced from 401 MPa (substrate) to 365 MPa. Relatively, LSP improved the fatigue strength to 451 MPa. Lastly, the fatigue morphologies were observed and the possible regain mechanism of fatigue strength was discussed. [ABSTRACT FROM AUTHOR]

In this work, the effects of Al* generated in situ in hydriding on the dehydriding of Mg-Al alloys prepared by Hydriding Combustion Synthesis (HCS) and Mechanical Milling (MM) were studied. Thermal analysis showed that the peak dehydriding temperature of MgH 2 was reduced by 25 °C (or 11 °C) when 20 at% Al was added in HCS (or MM) process, even though, the same dehydriding reaction of 17MgH 2 + 12Al*/Al → Al 12 Mg 17 + 17H 2 was observed. Isothermal dehydriding at 300 °C for 3 h demonstrated that it took 81 min for HCS+MM-MgH 2 to desorb 50% of hydrogen, while only 24 min was required for HCS+MM-Mg 80 Al* 20 . The apparent activation energy for dehydriding of MgH 2 was reduced from 144.3 ± 7.19 kJ/mol for HCS+MM-MgH 2 to 118.8 ± 6.73 kJ/mol for HCS+MM-Mg 90 Al* 10 . The scanning electron microscopy/energy dispersive spectroscopy and X-ray photoelectron spectroscopy analyses revealed that the Al* in situ generated from the hydriding of Al 12 Mg 17 in HCS would significantly decrease dehydriding temperature and improve dehydriding kinetics of the MgH 2 -Al composites because of a uniform distribution, the shortening reaction diffusion length, providing unoxidized surfaces to react with MgH 2 and the high chemical activity of Al*. [ABSTRACT FROM AUTHOR]

One key challenge in flexible batteries lies in the development of deformable/flexible electrode with high active materials mass loading and good electronic conductivity. Herein, we report such a paper-like TiO 2 /graphene-carbon nanotube hybrid electrode by a facile vacuum filtration approach. In this electrode, titania nanoparticles with uniform size (9 nm) and carbon nanotubes are embedded into graphene sheet homogeneously, forming a peculiar 3D conducting network. This feature ensures 1) a high TiO 2 mass loading (77.3 wt %, 2.93 mg cm −2 ); 2) good electric conductivity (∼1000 S m −1 ); and 3) good flexibility. Benefiting from these, the electrode delivers a high specific capacity (214 mAh g −1 ), excellent rate capability, and up to 700 cycles stability at a high rate of 1000 mA g −1 . This fabrication strategy demonstrates great practical potential and opens up new idea for high-performance self-supported electrode design. [ABSTRACT FROM AUTHOR]

A completely nickel-aluminum-copper (Ni-Al-Cu) layer was obtained through thermal diffusion process on a nickel-aluminum-bronze (NAB) substrate. The cumulative mass loss of the NAB alloy during the cavitation erosion tests was about 6.4 times and 5.5 times as large as that of the Ni-Al-Cu layer in distilled water and 3.5 wt% sodium chloride (NaCl), respectively. Electrochemical measurements under quiescence and cavitation erosion conditions were conducted to investigate the synergistic effects of cavitation erosion and corrosion. The results showed that the synergism had measurable effect on the cavitation erosion-corrosion process for both the NAB alloy and the Ni-Al-Cu layer. The total contribution of the cavitation erosion component including W E and W CIE was more than 80% and W E occupied the largest percentage. Thus, the improved cavitation erosion resistance of the Ni-Al-Cu layer was mainly due to mechanical factors, which implied a homogeneous and refined microstructure and the formation of hardened Ni 3 Al phase. [ABSTRACT FROM AUTHOR]

In the present paper, we reported a resistance type metal oxide semiconductor gas sensor based on platinum (Pt) activated titanium dioxide-molybdenum disulfide (TiO 2 -MoS 2 ) nanocomposites. The TiO 2 -MoS 2 nanocomposites were synthesized via a two-step hydrothermal method. Pt was added into the composites by dipping the composites into the ethanol solution of chloroplatinic acid and then annealed at 400 °C. The FE-SEM and TEM images showed the morphologies of the as-synthesized composites. Different mass ratios of TiO 2 and MoS 2 were attempted and the optimal composite was obtained. The hydrogen gas sensing properties of the sensors based on the optimal composite at operating temperature from room temperature to 150 °C were characterized, which indicated that the optimal operating temperature was 100 °C. The sensor also showed good selectivity to other flammable gases. In addition, we confirmed that Pt played an important role in enhancing the sensing performance. [ABSTRACT FROM AUTHOR]

In this work, two electrode materials, self-assembled camellia-like bismuth oxychloride (BiOCl) and monodispersed activated carbon microspheres (AC), were fabricated as a new asymmetric supercapacitor (ASC). The AC was synthesized using a renewable carbon source, and it was used as a positive electrode. A specific capacitance of 208 F g −1 at a current density of 1 A g −1 with the capacitance retention of 87.6% after 3000 cycles was obtained. On the other hand, an extremely facile and efficient approach for preparing BiOCl with a controllable morphology is proposed. The camellia-like morphology with a mesoporous structure of as-prepared BiOCl is revealed by SEM, TEM and BET characterization. The chemical composition of BiOCl is analyzed by XRD and XPS method. As a new negative electrode in ASC, the BiOCl electrode delivers a specific capacitance of 1243 F g −1 at 1 A g −1 , and 90.3% capacitance retention after 3000 cycles at 5 A g −1 . With coupled AC and BiOCl, the full cell of ASC exhibits a maximum capacitance value of 124 F g −1 at 0.5 A g −1 and good cycling stability with 82% of the initial specific capacitance after 3000 cycles at 1 A g −1 . [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT)-reinforced SiC f /SiC composites were prepared through in-situ growth of CNTs on SiC fiber via catalytic chemical vapor deposition (CCVD) and subsequent densification by precursor infiltration and pyrolysis (PIP) to optimize electromagnetic interference (EMI) shielding performance in the frequency range of 8.2–12.4 GHz. The influence of CNTs on the dielectric properties and EMI shielding properties of the SiC f /SiC composite were studied. The SEM/TEM morphology showed that the CNT network was formed on the surface of SiC fibers. The electrical conductivity of composites increased owing to the introduction of CNTs, leading to markedly increased conductive loss. Elevated CNT concentration was found to enhance complex permittivity and tan δ. Experimental results exhibited that absorption shielding effectiveness was the dominant EMI shielding mechanism. With the increase in CNT amount, the EMI total shielding effectiveness of the composite increased and reached a maximum of 39 dB with Co loading of 8%, an increase of 60% over that of plain SiC f /SiC composites. The achieved EMI shielding properties suggested the potential of CNT-reinforced SiC f /SiC composites as new-generation EMI shielding materials. [ABSTRACT FROM AUTHOR]

A novel kind of ternary nanocomposites, BaTiO 3 and NiFe 2 O 4 nanoparticles deposited on reduced graphene oxide nanosheets, was prepared via a three-step method. The phase structure, morphology, chemical composition, and magnetic properties were analyzed by powder X-ray diffraction (XRD) technique, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), Raman spectroscopy and vibrating sample magnetometry (VSM) while the microwave absorption performance was investigated by vector network analyzer (VNA). The results showed the sample with 30 wt% reduced graphene oxide exhibits the most remarkable microwave absorption properties. The optimal reflection loss can reach −51.1 dB at 9.52 GHz with a coating layer thickness of only 2.9 mm and a broad bandwidth (RL < −10 dB) of 3.12 GHz. [ABSTRACT FROM AUTHOR]

Metal hydroxides are welcomed in supercapacitor electrode applications. However, pristine metal hydroxides usually suffer from disadvantages of poor conductivity or agglomeration which may hinder their utilization. Hierarchical α-Ni(OH) 2 /CNTs hybrid is fabricated through one-step water bath method. Hierarchical α-Ni(OH) 2 grows along the direction of CNTs backbones. The electrochemical performance of α-Ni(OH) 2 /CNTs hybrid is superior to pristine α-Ni(OH) 2 according to electrochemical tests. High specific capacitance of the composite electrode reaches 2325 F g −1 at a sweep rate of 1 mV s −1 . Furthermore, longer cycle life of the hybrid is achieved. The hybrid displays 83.6% specific capacitance retention after 10000 cycles in contrast to pristine α-Ni(OH) 2 with only 49.5% capacitance retention. Hierarchical α-Ni(OH) 2 /CNTs composite with remarkable electrochemical performance may attribute to synergistic effects: good conductivity, redox property and high charge storage capacity. It is beneficial for the hybrid to get better electron storage capacity because of the Schottky barrier formed at interface between α-Ni(OH) 2 and CNTs. Those properties demonstrate that the hybrid has a potential application as supercapacitor electrode. [ABSTRACT FROM AUTHOR]

In this paper, plasma activated sintering was used to prepare powder metallurgy TC4 titanium alloys, and the effects of the sintering process on the densification, microstructure, phase transition and mechanical properties were investigated. The densities were evaluated by a drainage method. The microstructures and mechanical properties were characterized by OM, SEM, XRD, EBSD, and TEM methods, a universal testing machine and a Vickers hardness tester. The results showed that the PAS method could significantly shorten the sintering time and reduce the sintering temperature. With an increase in the sintering temperature, the sample changed from an equiaxed microstructure with short plate-like mixed-shaped grains to a double lamellar transitional structure. This structural change led to a decrease in the plastic deformation ability and an increase in the microhardness and compression strength of the sample. A coherent relation among the secondary α grains was observed, which had both a beneficial and detrimental effect on the material properties. A relative density of 98.11% and enhanced mechanical properties including an offset yield strength of 1034.09 MPa, a tensile strength of 1028.14 MPa, a Vickers hardness of 389.7 HV, and a sectional shrinkage of 28.4% were achieved and attributed to different microstructures controlled by the PAS sintering system. [ABSTRACT FROM AUTHOR]

Nb-20Si– x Mo ( x = 2,4,6)-based ultrahigh temperature alloys were prepared by high-vacuum non-consumable arc melting in a water-cooled copper crucible. The morphological evolution of the primary β-Nb 5 Si 3 phase in the Nb-Mo-Si-based alloys was discussed in detail based on the data of X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The results indicate that the phase constituents in the studied alloys consist of Nb solid-solution (Nbss) phase and β-Nb 5 Si 3 phase, with Nb 3 Si phases also appearing in the Nb-20Si-2Mo alloy. The Mo addition does not change the morphology of the primary β-Nb 5 Si 3 phase in the Nb-20Si alloy. The primary β-Nb 5 Si 3 phase in the investigated alloys displays various shapes, such as dendritic, L-like, hollow square and square ones. The morphological evolution of the primary β-Nb 5 Si 3 phase follows two main paths in the Nb-Mo-Si alloys. (I) At a lower cooling rate, the primary β-Nb 5 Si 3 morphology undergoes a transformation from L-like shapes to hollow square shapes before finally forming square shapes, and (II) at a higher cooling rate, the primary β-Nb 5 Si 3 morphology transforms from Y-like shapes to hollow square shapes and ends with forming square shapes. [ABSTRACT FROM AUTHOR]

A novel approach has been developed to cold spray fully dense Cu deposits by using a mixed feedstock. The feedstock is composed of two raw powders with remarkably dissimilar microstructure and hardness: a hard and dense gas-atomized Cu powder (GA Cu) and a soft and porous electrolytic Cu powder (E Cu). It was found that when high velocity impact occurs between dissimilar Cu particles, the plastic deformation shows an asymmetrical feature and the strain is mainly concentrated on the soft side. This asymmetrical deformation behavior ensures that all the inter-particle space can be filled by the deformed soft particles and leads to a fully dense microstructure. An increment of ∼44% in deposition efficiency was achieved for the mixed feedstock as compared with the GA Cu powder. A high in-plane electrical conductivity of 79 %IACS (73 and 56 %IACS for GA coating and E coating, respectively) and high through thickness thermal conductivity of 285.6 W m −1 K −1 (207.1 and 133.8 W m −1 K −1 for GA coating and E coating, respectively) were achieved. The coating prepared by mixed powders shows an excellent corrosion resistance, comparable with that of the bulk Cu. This work gives a new strategy to improve the inter-particle bonding and get fully dense metallic deposits by feedstock design rather than spraying condition optimization. [ABSTRACT FROM AUTHOR]

A hot-extruded AZ80 Mg alloy rod was subjected to pre-treatments and post-hot compression in this work. Microstructure evolutions and resultant mechanical properties were investigated using samples with different states. The sample processed by solid solution and pre-aging (SSA) contained large-scale precipitates at the triple points of grain boundaries, while the sample processed by solid solution, pre-deformation and pre-aging (SSPDA) contained fine precipitates and different types of dislocations in the {10–12} twin interiors. Meanwhile, substructures were formed through dislocations surrounding the fine precipitates in SSPDA sample. During hot compression at 593 K, continuous dynamic recrystallization (DRX) was promoted by substructures in SSPDA sample, resulting in a full development of fine grains and a weakened texture. Inversely, discontinuous DRX happened in SSA sample, resulting in a low volume fraction of DRX grains and a relatively strong texture. The tensile testing showed that SSPDA sample had much higher strength and ductility than those of SSA sample. The enhanced mechanical properties were attributed to the completely developed DRX with grain refinement and texture weakening. [ABSTRACT FROM AUTHOR]

Hot compression experiments are performed to study the flow characteristics of a homogenized Sr-modified Al-Si-Mg alloy at the temperatures of 300–420 °C and strain rates of 0.01–10 s −1 . It is found that the deformed grains and Si-containing dispersoids clusters in the matrix are elongated, and incomplete DRX is discovered on the elongated boundaries at high deformation temperatures. The non-uniform distribution of Si-containing dispersoids, soft dispersoid free zones (DFZs) and fragmentation of plate-shaped phases may cause the flow instability at high strain rates. The Si morphology in the homogenized state can be further modified by the subsequent thermo-mechanical deformation. Moreover, the flow stress first rises to the peak with the increase of strain because of strain hardening, and then slowly declines with the further straining owing to the occurrence of incomplete DRX and coarsening of Si-containing dispersoids. The high activation energy is closely associated with the dislocations pinning from Si-containing dispersoids. Additionally, taking the coupling impacts of temperature, strain and strain rate into consideration, an extended phenomenological model compensating softening effects is developed to depict the strain hardening behavior, as well as dynamic softening characteristic. The developed model is validated by the experimental results, and can be applied to accurately predict the flow stresses of the studied Al-Si-Mg alloy during high temperature deformation. [ABSTRACT FROM AUTHOR]

The Tm 3+ -doped NaYbF 4 upconverting nanoparticles were fabricated by a facile hydrothermal method and they were characterized by X-ray diffraction and transmission electron microscopy as well as upconversion (UC) emission spectrum. Under the irradiation of 980 nm light, the as-prepared samples exhibited bright visible UC emissions originating from the intra-4f transitions of Tm 3+ ions. The pump power-dependent UC emission spectra were measured to elaborate the involved UC mechanism. Furthermore, the temperature-dependent fluorescence intensity ratio from the thermally coupled levels ( 3 F 2,3 and 3 H 4 ) of Tm 3+ ions was obtained to analyze the thermometric performances of the studied compounds. It is evident that the reaction temperature can not only improve the UC emission intensity of the Tm 3+ -doped NaYbF 4 upconverting nanoparticles, but also modify its sensor sensitivity. Meanwhile, the maximum sensor sensitivity was found to be as high as 2.1 × 10 −4  K −1 with a wide temperature range of 298–778 K, suggesting its potential application for physiological temperature sensing in biological tissues and cells. Ultimately, the Judd-Ofelt theory was employed to clarify the effect of reaction temperature on the temperature sensitivity. [ABSTRACT FROM AUTHOR]

Developing metal oxide nanocomposite with superior gas-sensing properties is an important subject in the field of gas sensor. In this paper, we reported a facile synthesis route for ZnFe 2 O 4 /α-Fe 2 O 3 porous microrods (PMRs) by using dual oxalates as sacrificial template. FeC 2 O 4 ·2H 2 O solid microrods (SMRs) were first synthesized by a chemical precipitation reaction between FeSO 4 ·7H 2 O and H 2 C 2 O 4 ·2H 2 O, which were then immersed in Zn 2+ aqueous solution to obtain the hybrid ZnC 2 O 4 ·2H 2 O/FeC 2 O 4 ·2H 2 O SMRs through the substitution reaction between Zn 2+ and Fe 2+ . After a proper annealing process, ZnFe 2 O 4 /α-Fe 2 O 3 PMRs were successfully prepared through the decomposition of ZnC 2 O 4 ·2H 2 O/FeC 2 O 4 ·2H 2 O SMRs. The prepared ZnFe 2 O 4 /α-Fe 2 O 3 PMRs are about 2–5 μm in length and 0.3–0.5 μm in diameter, and constructed by numerous loosely stacked nanoparticles with the size about 15 nm. The dominant pore size in ZnFe 2 O 4 /α-Fe 2 O 3 PMRs is around 10 nm. The results of gas-sensing tests indicates that through decorating the α-Fe 2 O 3 PMRs with ZnFe 2 O 4 , the response of the sensor towards TEA is remarkably improved. For example, the response of the composite sensor to 100 ppm TEA is as high as 42.4, which is about 20 times higher than that of the bare α-Fe 2 O 3 PMRs sensor (2.5). The enhanced TEA sensing mechanism of ZnFe 2 O 4 /α-Fe 2 O 3 PMRs was discussed in detail. [ABSTRACT FROM AUTHOR]

Second phase particles (SPPs) that are formed during melting process have a significant effect on the hot extrusion and re-extrusion processes of NiTi. In the present work, the evolution of Ti 4 Ni 2 O x (with x ≤ 1) particles during hot extrusion and re-extrusion of near equiatomic Ti-50.6 at.% Ni billets, and their effects on the surrounding matrix microstructure were studied using OM, SEM, TEM and EBSD. The analyses indicate that Ti 4 Ni 2 O x (with x ≤ 1) are the particles that precipitate in the austenite matrix. After hot extrusion and re-extrusion, some particles are elongated and preferentially oriented along the ED. Eventually, these elongated particles are located at the grain boundaries. The size distribution of the SPPs is non-uniform after the first hot extrusion, and this non-uniformity increases after re-extrusion. The presence of non-deforming SPPs produces inhomogeneous deformation with a sharp increase in dislocation density in the surrounding matrix. This is shown to exert a profound effect on the processes of recovery and recrystallization for the surrounding matrix. [ABSTRACT FROM AUTHOR]

In this study, a 5–10-nm-thick Y 2 O 3 layer is employed as a surface-coating layer on (lithium-manganese)-rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNCO) cathode materials for the first time. The results indicate that the bulk structure of LMNCO is unchanged with the additional Y 2 O 3 coating, and the electrochemical properties, including initial coulombic efficiency, cycle stability and rate performance, are greatly enhanced in these coated materials. In particular, the 2.0 wt% Y 2 O 3 -coated LMNCO expresses an initial discharge capacity of 280.3 mAhg −1 with capacity retention of 89.1% at a 0.5 C rate after 200 cycles, which is much better than that of 76.3% of the pristine sample. Furthermore, electrochemical impedance spectroscopy demonstrates that the Y 2 O 3 -coating layer can protect the LMNCO from being impaired by the electrolyte and can make contributions to reduce the cathode charge-transfer resistance at the delithiated condition. These findings offer new research directions for solving serious defects, such as a large proportion of initial nonreversible capacity loss and poor cycling stability, in lithium-rich cathode materials used for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Mullite-based ceramic tiles were successfully prepared using only high-alumina fly ash (HAFA) at relatively low sintering temperatures (1100–1400 °C). The effects of alkali activation on the chemical composition, mineral phase, and morphology of the HAFA were respectively characterised by ICP-OES, XRD, and SEM methods. The alkali-activation pretreatment not only modifies the chemical composition of HAFA to match that of mullite, but also can introduce Na-rich compounds to promote sintering. The macroscopic and microscopic characteristics of the fully ash-based ceramic tiles formed at different sintering temperatures were examined. The ceramic samples sintered at 1300 °C exhibited optimal post-sintering properties (relative density: 90.85%, water absorption: 0.10%, rupture modulus: 109.67 MPa, linear shrinkage: 15.70%, and apparent porosity: 0.68%) and a well-developed cubic puncheon-shaped mullite morphology. Finally, through the isothermal sintering method, the melt viscosities and the sintering kinetics were calculated theoretically, and the results show that the alkali activation could dramatically reduce the melt viscosity and the apparent activation energy. This research may provide a new method in utilising the vast amounts of HAFA waste to produce mullite-based ceramic tiles at low costs. [ABSTRACT FROM AUTHOR]

Carbon can be metal, semiconductor or insulator depending on its structures, and its conductivity can be one-dimensional (1D), 2D, and 3D correspondingly. Boron Nitride (BN) is isoelectronic to carbon, but one prominent difference between the two systems is their electronic properties. For many years, the synthesized and predicted BN allotropes were always insulators, irrespective of their structures. In this paper, with the help of structures searching based on first-principles calculations, a sp 2 / sp 3 -hybridized metallic monoclinic 3D BN ( M -BN) structure is proposed. M -BN can be viewed as puckered hexagonal-BN (h-BN) layers bucked by partial sp 3 B N bonds. The electronic property analysis revealed that the metallicity of M -BN is attributed to the delocalized 2 p electrons of the sp 2 B and N atoms. The metallic B atoms and N atoms are aligns in two arrays along a 1D axial direction, resulting in the unusual 1D dual-threaded conduction in 3D M -BN structure. The enthalpy calculation have revealed that M -BN is the most energetically favorable structure among the predicted metallic BN structures so far, and it might be obtained via compressing layered h-BN precursor theoretically. Due to the 3D strong framework, M -BN has an estimated Vickers Hardness of 33.7 GPa, indicating it is a potential hard material with novel 1D conduction. [ABSTRACT FROM AUTHOR]

The investigation on phase equilibria of Mg-La-Zr system contributes to finding the alloy composition with good mechanical properties and superior thermal conductivity along with the variation of phase constitution and microstructure. In our study, four key Mg-La alloys were used to investigate the phase equilibria of Mg-La binary system via a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS). Two peritectic reactions have been found among the composition of 50.0–75.0 at.% Mg. It is determined that LaMg 2 is a stable phase below 500 °C, while La 5 Mg 41 is not stable in Mg-La system. The phase equilibria of Mg-La-Zr were investigated through one diffusion couple of Mg/La 84.6 Zr 15.4 and three Mg-La-Zr alloys. The thermodynamic description of the Mg-La-Zr system was assessed at 300–500 °C. By the calculation of equilibrium solidification of Mg-La-Zr alloys, it is predicted that with the increase of La content, eutectic regions composed of LaMg 12 and magnesium phase present a dense network in grain boundary of primary hcp(Mg) which hinder the heat transmission. Mg 99.7 La 0.2 Zr 0.1 (136.6 W/(m·K)) exhibits higher thermal conductivity than Mg 99.1 La 0.8 Zr 0.1 (113.9 W/(m·K)). [ABSTRACT FROM AUTHOR]

A hydrophobic surface has been prepared on the surface of an extruded Mg–5Sn–1Zn (TZ51) alloy by micro-arc oxidation (MAO) with a subsequent stearic acid (SA) modification. The maximum water contact angle of 122.5° can be obtained by the MAO at 400V for 5min with the SA modification, which can be attributed to the rough island-structures and volcano-like structures with the formation of the SA coating. Both the hydrophobic surface and MAO coating effectively inhibit the corrosion of the extruded TZ51 alloy. The corrosion current decreases from 8.9 μA cm −2 to 0.07 μA cm −2 and the polarization resistance increases from 2.11 to 434.30 11 kΩ cm 2 without changing corrosion potential (−1.53 V (vs. SCE)) after MAO at 400V for 5min MAO with subsequent SA treatment, indicating the effective corrosion inhibition of hydrophobic surface and the MAO coating. Main results obtained will shed some light on hydrophobicity of a new type of Mg–Sn–Zn system, which is critical to the exploration of new Mg alloys with strong corrosion resistance for potential applications in biomaterials or industrial fields. [ABSTRACT FROM AUTHOR]

High-voltage spinel LiNi 0.5 Mn 1.5 O 4 cathode results in 4.7 V Li-ion batteries with a high power capability, but the electrochemical performances are limited by electrode/electrolyte interfacial reactivity at high potential. We demonstrate here that using a new electrolyte additive based on LiFSI, LiNi 0.5 Mn 1.5 O 4 //Li cells upon cycling show reduced capacity fading and improved coulombic efficiency. The capacity retention after 200 th cycle is ∼96% using the electrolyte additive, compared with ∼89% without the electrolyte additive. The coulombic efficiency for cells with the electrolyte additive shows an increase from ∼96.5% to ∼98.5%. Detailed X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy measurements reveal that LiPF 6 degradation during cycling via formation of a passivation film at the surface of the electrode. Our results further reveals that the surface film is composed of organic compounds resulting from degradation of the electrolyte additive. The formed surface film is much thicker (∼5 nm) but less resistive on the electrode cycled with the electrolyte additive, compared with that without the electrolyte additive. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide modified by silver nanoparticles (Ag-RGO) has been employed as a reinforcing component to prepare the copper matrix composites. The Cu composites with 0.6 vol% Ag-RGO exhibit a significant improvement in the yield strength and ultimate tensile strength, being approximately 98% and 93% higher than that of pure Cu, respectively, much better than the RGO/Cu composites. Simultaneously, the electrical conductivity of Ag-RGO/Cu composites could reach 92.69% IACS. The significant strength enhancement is attributed to the addition of Ag nanoparticles which prevent the agglomeration of the RGO and enhance adhesion between the RGO and the Cu matrix. The results indicated that Ag-RGO is an effective reinforcing component to improve the mechanical properties of the graphene/metal composites. [ABSTRACT FROM AUTHOR]

Combination of CeO 2 chunks and carbon nanotubes (CNTs) as supercapacitor electrode material is fabricated. Superior electrochemical performance including high specific capacitance and long term cycling stability is exhibited through electrochemical tests; the CeO 2 /CNTs electrode achieves specific capacitance reaching 818 F g −1 at scan rate of 1 mV s −1 . The hybrid displays excellent capacitance retention of 95.3% after 2000 cycles. The electrochemical property is attributed to the redox properties, good electrical conductivity and synergistic effect of two materials. With the Schottky barrier at CeO 2 /CNTs interface, electrons can be accumulated at the Fermi level. More electrons can be released in the process of discharge. It is demonstrated that this kind of nanocomposites could be a promising candidate as electrode material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

In the work, 3-dimensional (3D) flower-like NiFe 2 O 4 was prepared for the removal of water contaminants via a facile hydrothermal method and using Ni foam as substrate. The as-prepared NiFe 2 O 4 was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Nitrogen adsorption-desorption, vibrating sample magnetometer and Fourier transformed infrared. The as-prepared NiFe 2 O 4 owns a high specific surface which is favorable for adsorption of water contaminants. And the magnetic property of the as-prepared material, which is also preferred in wastewater treatment, makes it easy to be separated from the water. To investigate adsorption behavior, UV–visible spectrophotometer, adsorption isotherm and adsorption kinetics were studied. It is demonstrated that the adsorption process fits well with the Langmuir model and the pseudo-second-order model. The maximum adsorbing capacity ( q m ) of the 3D flower-like NiFe 2 O 4 for Congo red adsorption was 229.89 mg g −1 , and the adsorption capacity reached 80% in 10 min. The enhanced results suggest that the as-prepared 3D flower-like NiFe 2 O 4 is a potential adsorbent for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

We prepared the high quality polycrystalline β -CrPO 4 with the cycloidal spiral spin magnetic structure. The multiferroicity is investigated by means of magnetic, heat-capacity, dielectric and ferroelectric polarization measurements. At the Neel temperature T ∼23 K, it is the transition into a spiral magnetic ordered phase, there is an anomaly in the dielectric and heat-capacity data, and the ferroelectric polarization appears. The ferroelectric polarization can be attributed to the cycloidal spiral magnetic ordering, which coincides well with the inverse Dzyaloshinskii-Moriya interaction scenario or the spin-current scenario. The magnitude of ferroelectric polarization decreases with increasing the applied magnetic field, which indicates there is the strong coupling between ferroelectric polarization and magnetism in β -CrPO 4 . [ABSTRACT FROM AUTHOR]

Using a new design strategy for the metastable phase in transformation induced plasticity (TRIP) steels, we have successfully manufactured a 7 wt.% Mn containing steel with an excellent combination of mechanical properties (950 MPa ultimate tensile strength and 63% total elongation) via warm rolling and intercritical annealing (IA) processes. Compared with the cold rolled microstructure that is usually completely recrystallized during annealing, the warm rolled microstructure is just partially recrystallized due to the lower driving force that is accumulated. This leads to about 50 vol.% of the retained austenite grains having both lamellar and equiaxed morphologies after IA, with the latter having a wide and almost evenly spaced size distribution. In-situ synchrotron X-ray examination revealed that about 40 vol.% of the retained austenite grains could transform to martensite in a sustainable way during deformation because they had a range of mechanical stability owing to their different morphologies and wide size distributions. Moreover, the partitioning of the solute elements during IA leads to some austenite grains having proper values of stacking fault energy using which they can twin during deformation. Finally, the retained austenite grains in the medium-Mn steel can either transform to martensite gradually or twin during deformation, and contribute to large elongation at high strengths via both TRIP-assisted and TWIP effects. [ABSTRACT FROM AUTHOR]

The effects of random anisotropy on the magnetic transition and magnetic entropy change (MEC) have been investigated in a series of Gd-Er-Al-Co metallic glasses(MGs) through Er addition. The Gd-based metallic glass without Er shows typical ferromagnetic transition. With Er addition, the Curie temperature decreases and a re-entrant spin glass like behavior can be observed due to the frustration among random magnetic anisotropy (RMA) and exchange interactions. A large maximum MEC of 9.1 J kg −1 K −1 around 117.5 K is obtained in Gd 56 Co 24 Al 20 MG, which can be tuned continuously in a wide temperature range (117.5–17.5 K) by introducing Er without impairing the good glass forming ability. A largest peak MEC of 12.6 J kg −1 K −1 has been obtained around 17.5 K in Gd 8 Er 48 Co 24 Al 20 . Significantly, the exponent n of field dependence of MEC is found to depend on the degree of magnetic frustration among RMA and exchange interactions. [ABSTRACT FROM AUTHOR]

The microstructural evolution, phase constitution and mechanical properties of directionally solidified Mg-5.5Zn-xGd (x = 0.8, 2.0, and 4.0) alloys were firstly investigated under G = 30 K/mm at a wide range of V (10 μ m/s - 100 μ m/s). It was confirmed that there existed α (Mg) + I(Mg 3 Zn 6 Gd) in Mg-5.5Zn-0.8Gd alloy, and α (Mg) + I(Mg 3 Zn 6 Gd) + W(Mg 3 Zn 3 Gd 2 ) in Mg-5.5Zn-(2.0, 4.0)Gd alloys, respectively. The criterion growth rate for cellular-columnar dendrite transition (CDT) for Mg-5.5Zn-xGd alloys decreased with the increase of Gd content. The relationships between the microstructural parameters ( λ 1 , λ 2 ) and V for Mg-5.5Zn-xGd alloys were established using a linear regression analysis. The values of λ 1 and λ 2 decreased exponentially with the increase of V and the exponent values were found to be close to the theory values of 1/4 and 1/3, respectively. The tensile test showed that the room temperature ultimate tensile strength (UTS) increased and the elongation decreased with the increase of the growth rate for a certain composition of Mg-5.5Zn-xGd alloy. For a certain growth rate, UTS first increased from 0 wt % to 2.0 wt % of Gd content, and then decreased with the further increase of Gd content. The directionally solidified Mg-5.5Zn-2.0Gd experimental alloy showed the maximum ultimate tensile strength. [ABSTRACT FROM AUTHOR]

Cobalt-doped magnesium aluminate spinel (Co:MgAl 2 O 4 ) could be the most effective saturable absorber (SA) for Q-switching solid-state lasers operating at 1.5 μm. Using LiF as the sintering aid, highly transparent Co:MgAl 2 O 4 ceramics were fabricated by hot pressing (HP) of the commercial spinel and the co-precipitated Co:MgAl 2 O 4 powder mixture. The optical properties of Co:MgAl 2 O 4 ceramics were investigated, and the ground state absorption cross section (σ gas ) of Co 2+ was calculated from the curve of the absorption coefficient. For the Co:MgAl 2 O 4 ceramics hot-pressed at 1600 °C for 2 h under 30 MPa with 1 wt.% LiF addition, the in-line transmittance reaches about 77% at 1000 nm and 1700 nm, and the ground state absorption cross section of Co 2+ is 2.55 × 10 −19 cm 2 at the wavelength of 1540 nm, which is promising as a saturable absorber for solid-state pulse laser operating at 1.5 μm. [ABSTRACT FROM AUTHOR]

Li-rich layered oxides, one of the most promising cathodes for high energy Li-ion batteries, commonly undergo some issues such as poor rate performance, low Coulombic efficiency, voltage degradation and so on. In this work, Li 1.18 Mn 0.56 Ni 0.13 Co 0.13 O 2 cathodes with excellent rate capability and cycling stability are prepared by a new molten-salt method using KCl and NaCl as complex flux. The electrochemical tests show that these cathodes can deliver an initial discharge specific capacity of 224.3 mA h g −1 at 300 mA g −1 . Meanwhile, the capacity retention ratio remains 92.1% after 100 cycles. The outstanding electrochemical performance is mainly attributed to the uniform distribution of TM-elements in Li 1.18 Mn 0.56 Ni 0.13 Co 0.13 O 2 cathodes, which can promote the electrochemical activation of Li 2 MnO 3 -like component. Especially, it is found that the uniformity of TM elements in Li-rich cathodes can be improved by choosing molten-salt method as the synthetic strategy. [ABSTRACT FROM AUTHOR]

A three-dimensional porous carbon skeleton with hexagonal channels was synthesized by using mollusc shell as the carbon source. The obtained mollusc shell based macroporous carbon material (MSBPC) has high conductivity and is very favorable for use in the electrolyte penetration and electron transfer, making it an excellent carbon substrate for composite electrode materials. After incorporation of MnO 2 nanosheets, the MSBPC/MnO 2 was synthesized and applied in supercapacitors, which exhibited a high specific capacitance of 386 F g −1 at 1 A g −1 with an excellent rate performance (278.7 F g −1 at 10 A g −1 ), and outstanding cycling stability, with a capacitance retention of 83% after 5000 cycles at 20 A g −1 . The good electrochemical performance indicates the high potential of the prepared MSBPC/MnO 2 as a novel supercapacitor electrode material with a high power density, excellent long life cycling, and environmental friendliness. [ABSTRACT FROM AUTHOR]

SiC fiber-reinforced Ti-21Al-29Nb matrix composites with either C and C/Mo duplex coatings were prepared by the foil-fiber-foil (FFF) method, in order to comparatively study the effects of C/Mo duplex coatings on the interface and mechanical properties of the composites. The longitudinal tensile strength of the as-prepared composites was measured at room temperature. In order to study the interfacial thermal stability and microstructure evolution characteristics of the composites, vacuum thermal exposures of the composites were carried out at 800, 900 or 940 °C for different durations. The interfacial microstructures of the as-prepared and thermally-exposed composites were investigated by means of scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The results indicate that the C/Mo duplex coating does not only have better thermal stability, but also can further slow down the interfacial reaction of the composites in comparison with the C single coating. The diffusion of a small amount of Mo atoms made the matrix close to the interface have better plasticity, so the tensile strength of the composites can be further improved. The interface of the composite with the C/Mo duplex coating was nearly intact after the 940 °C/50 h thermal exposure while that of the composite with the C single coating was not intact, as the C/Mo duplex coating can better relax the thermal residual stresses than the C single coating. [ABSTRACT FROM AUTHOR]

Electrodeposited Co-P coatings are a potential replacement for electrolytic hard chrome coatings in critical engineering applications. The superior performance of the Co-P coatings is derived from as-deposited microstructures consisting of metastable crystalline and amorphous phases. These microstructures depend upon the deposition conditions and, in particular, on the P content. In this study, Co-P coatings with P contents of 6.4–28.4 at.% were produced by DC electrodeposition onto low alloy steel coupons. The coatings were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The initial deposit microstructures are either crystalline (<10.0 at.% P), hybrid crystalline/amorphous (10.0–12.1 at.% P) or amorphous (>12.1 at.% P). The thermal signatures within each microstructural class were determined by DSC to identify the temperatures at which transformations occur in these metastable microstructures. The transformation products were then identified by XRD and TEM on samples of the deposits annealed isothermally in the DSC. These data show that: the crystalline deposits transform to an equilibrium mixture of HCP-Co and Co 2 P by precipitation of the phosphide from the initially supersaturated HCP-Co; the amorphous deposits crystallize to form a mixture of metastable FCC-Co and Co 2 P; and the hybrid deposits transform to a mixture of the products observed for the crystalline and amorphous deposits. The activation energies of the processes involved were obtained by Kissinger analysis on the scan-rate dependence of the peak temperatures in the DSC curves. The transformation mechanisms were then deduced by comparing these values with published values for such systems in the literature. [ABSTRACT FROM AUTHOR]