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MXene is considered as a kind of promising two-dimensional layered carbide/nitride in the field of overall water splitting attributed to hydrophilic surface, controllable interlayer spacing, and desirable metal conductivity. Nevertheless, the re-stack effect still hinders its large-scale development. Therefore, in this work, metal-organic frameworks-derived hollow CoV 2 O 6 nanocubes anchored on the surface of lattice tensile strained V 2 CT x MXene (TS-V 2 CT x /CoV 2 O 6 HN) as electrocatalysts are prepared through ion exchange process and the following liquid nitrogen quenching treatment. Lattice tensile strain could boost ions transfer of transition metals due to the enlarger interlayer spacing. The heterostructure between CoV 2 O 6 and V 2 CT x MXene could optimize the adsorption energy of H- and O-containing intermediates to obtain the best ΔGH* for hydrogen evolution reaction (HER) and decrease the ΔG value of rate determining step for oxygen evolution reaction (OER). Besides, the CoV 2 O 6 components acting as intercalation agents could avoid the self-aggregation of MXene nanosheets. Simultaneously, the hollow structure also offers high active area to promote electrolyte permeation and accelerate electron/ion transfer. As a consequence, the TS-V 2 CT x /CoV 2 O 6 HN acquires extraordinary HER and OER performance with the overpotential of 32.2 and 235.0 mV at the current density of − 10 mA/cm2 and 10 mA/cm2, respectively, which is quite remarkable compared to the recent MXene-based electrocatalysts. Moreover, the overall water splitting device assembled by TS-V 2 CT x /CoV 2 O 6 HN demonstrates a low cell voltage of 1.358 V at 10 mA/cm2. Thence, this work donates an exciting avenue to overcome the re-stack issue of V 2 CT x MXene, constructing a superior electrocatalyst with high activity and desirable reaction kinetics. [Display omitted] • The hollow CoV 2 O 6 nanocubes anchored on the surface of lattice tensile strained V 2 CT x MXene are successfully prepared. • Lattice tensile strain could change the local atomic/electronic environment and widen interlayer spacing. • The hollow structure could offer rich active area and effectively avoid the self-aggregation of MXene sheets. • TS-V 2 CT x /CoV 2 O 6 HN acquires extraordinary hydrogen evolution reaction and oxygen evolution reaction activity. • This work could offer an exciting avenue for overcoming the re-stack issue of V 2 CT x MXene. [ABSTRACT FROM AUTHOR]

Abstract NiFe 2 O 4 fusiformis was derived from Ni/Fe bimetal metal-organic frameworks (MOFs) precursors prepared using a facile hydrothermal method, and the corresponding morphology, microstructure, and gas sensing properties were investigated. After thermal treatment at 350 °C in air, the Ni/Fe MOFs ellipsoid were completely converted into NiFe 2 O 4 fusiformis, leading to a big volume shrink because of the removing of organic ligands. The NiFe 2 O 4 fusiformis was used to fabricate gas sensor to detect xylene operating at 300 °C. The sensor exhibited a good response sensitivity of 31.52 with response/recovery time of 50.10 s/40.30 s, respectively, toward 500 ppm xylene. It also showed a remarkably high selectivity to xylene against other gases such as toluene, ethanol, methanol, acetone, isopropanol, ammonia, formaldehyde, and benzene. The excellent performance could be ascribed to the nature and the unique morphology of as-prepared NiFe 2 O 4 with high specific surface area (60.50 m2/g) and porous microstructure. These findings may render a new opportunity to fabricate gas sensor for xylene detection based on p-type NiFe 2 O 4. Graphical abstract Image 1 Highlights • NiFe 2 O 4 fusiformis was derived from Ni/Fe bimetal metal-organic frameworks (MOFs). • A bid volume shrink was observed from Ni/Fe MOFs to NiFe 2 O 4 after thermal treatment. • The NiFe 2 O 4 fusiformis is composed of numerous primary nanoparticles. • The NiFe 2 O 4 based sensor shows highly selective response to xylene at 300 °C. [ABSTRACT FROM AUTHOR]

Abstract Cu matrix composites reinforced with 0-3 wt% CNTs are fabricated via molecular-level mixing, microwave sintering and rolling technology. A homogeneous distribution of CNTs is exhibited in copper matrix. Clean CNTs/Cu interfaces perform high bonding strength. Electrical conductivity and relative density of microwave sintered CNTs/Cu composites decrease with increase in CNTs content. There exists maximum for hardness of CNTs/Cu composites which rise and then fall with the rise of CNTs content. When CNT contents are less than 1 wt%, it provides a good control over microstructures with low porosity and small pore size. Subsequent rolling process enables better microstructure and performance of sintered composites which shows tensile strength of 218 MPa, the elongation of 37.75%, and the electrical conductivity of >98% IACS compared to pure copper. Our studies provide a robust approach to high-performance CNTs/Cu composites by microwave sintering. Highlights • The CNTs/Cu composite powders were synthesized by molecular-level mixing. • Rapid densification of the CNTs/Cu composite powders was achieved by microwave sintering. • CNTs/Cu composites exhibit significant improvements in ductility and electrical conductivity. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon has attracted extensive attention because of its unique form, wide range of sources and low cost. However, the construction of efficient biomass-based microwave absorbers with hierarchical structures and multicomponent magnetic/dielectric structures remains a great challenge. Therefore, CoNi-MOF was self-assembled in situ on the plant Juncus effusus by the microwave method, and CoNi/NC/C composites were prepared by in situ pyrolysis in a nitrogen atmosphere. The morphology, electromagnetic parameters, specific surface area and porous structure of the composites were adjusted by controlling the pyrolysis temperature. For a pyrolysis temperature of 600 ℃ and filling of 16 wt%, the composite was found to show an RL min value of − 64.3 dB at 12.88 GHz at a thickness of 2.5 mm, and the effective absorption bandwidth (EAB)reached 7.36 GHz. The excellent microwave absorption performance was attributed to conduction loss, dipole polarization, interface polarization, magnetic loss and balanced impedance matching. • Multimodal 3D structure CoNi / NC / C composites were synthesized by microwave and pyrolysis. • The RLmin of the sample was − 64.3 dB at 2.5 mm, with a broad effective bandwidth of 7.36 GHz. • Metal-O-C and Metal-N bonds were present in the composites. • The performance derives from multiple loss mechanism and tunable impedance match. [ABSTRACT FROM AUTHOR]

Lanthanum-doped titanium-zirconium-molybdenum (La-TZM) alloy was prepared by powder metallurgy and rolling process. The processing crack and crack initiation mechanisms of La-TZM alloy after sintering, hot rolling and cold rolling were studied by scanning and transmission electron microscopy. The results show that the doped La(NO 3 ) 3 , TiH 2 and ZrH 2 have finer secondary phase in the La-TZM alloy plate. The fracture mode of sintering billet is inter-granular, but the fracture surface of hot rolling exhibited transgranular cleavage. However, the cold rolling is quasi-cleavage fracture. The secondary phase particles tend to hinder the movement of dislocations causing dislocations pile-up. The resulting tensile stress can accelerate cracks nucleation and growth, and the crack propagation will be deflected by the secondary phase particles. The crack initiation can be avoided by reducing local stress concentration caused by dislocations. [ABSTRACT FROM AUTHOR]

Silicon anode is a promising candidate for the next generation electrodes for lithium ion batteries. However, the poor cycle performance of silicon caused by large volume expansion of silicon hinders the practical application of silicon anode. The large volume change results in the reformed solid electrolyte interface layer and the electrode/electrolyte interface is unstable. In this work, the native silica and N-doped carbon layer improve the stability of active particles/electrolyte interface and accommodate volume change so as to enhance the electrochemical performance of silicon-based anode material. The temperature has an effect on the growth of the oxide layer and electrochemical performance of electrode material. Superficial silica content on silicon particles increases as the temperature rises, and the cycle properties are improved as well. The sample presents the proper thickness of the silica layer and the composition of the carbon layer at 800 °C. Electrochemical tests show the sample delivers a capacity of 961.9 mAh g −1 at 100 mA g −1 , with initial coulombic efficiency of 84.5%. Reversible specific capacity of 775.7 mAh g −1 is obtained at 200 mA g −1 after 50 cycles, with capacity retention of 86.1%. It also exhibits good cycling performance with a reversible capacity of 484.6 mAh g −1 at 1 A g −1 after 200 cycles. [ABSTRACT FROM AUTHOR]

The practical application of a high-capacity silicon anode is still impeded by its interfacial instability, low electronic conductivity, and compact density. Here, we propose a coralline-like Si/Ni/C anode material by utilizing a metal-organic framework as the metal and carbon source. By coreduction and carbonization of silica-coated Ni-MOF, an interlayer of NiSi 2 is in situ formed at the interface of the carbon skeleton and Si nanoparticles, resulting in excellent compatibility and gradient interface between them. The efficiently utilized inner void, containing multiple Si, NiSi 2 , and carbon skeleton, improves the compact density of the as-prepared Si/Ni/C. The electronic conductivity was also improved by the bridge space between the carbon skeleton and Si nanoparticles through a highly conductive NiSi 2. The three-dimensional coral carbon skeleton provides excellent mechanical properties and suitable space for the volume change of Si. As a result, the as-prepared Si/Ni/C composite demonstrates a high reversible capacity of 1044 mA h g−1 with a capacity retention of 82.4 % after 100 cycles. The carbon-coated Si/Ni/C composite exhibits enhanced rate capability (695 mA h g−1at 10 A g−1). Such improved performances are attributed to the synergetic effects of stable structural integrity and good interface stability, which can be used to guide the design of Si anode for industrial applications. • Porous Ni-MOFs provide a three-dimensional conductive network. • The microstructure and nanointerface synergistically increase the tap density. • Si/Ni/C exhibits excellent rate capability with a specific capacity of 695 mA h g−1 at 10 A g−1. [ABSTRACT FROM AUTHOR]

● Multifunctional zinc-based acrylate resins for marine antifouling and EM wave absorption were prepared and researched. ● The resins effectively inhibited the growth and adhesion of bacteria (>90%) and algae (optimal: 92.5%). ● The ARZn-x without antifoulants can maintain their antifouling properties for more than 4 months in marine. ● RL min was -40.18 dB at 1.5 mm and 30.55 GHz, and full absorption was achieved in the range of 1.0 ~ 5.5 mm at 18-40 GHz. [Display omitted] Here, we report on the marine antifouling performance and electromagnetic wave absorption (EMWA) properties of multifunctional zinc-based acrylate resins (ARZn-x). Their controlled hydrolysis with varying contents of carboxylic acid groups and ZnO led to formation of new surfaces that contributed to excellent antibacterial activity (>90%) and reductions in algal adhesion (optimal: 92.5%). Marine field tests demonstrated ideal antifouling performance during immersion in seawater for 4 months, and the coatings inhibited the adhesion and growth of biofouling species in marine. Furthermore, the ARZn-x resin coatings exhibited remarkable EMWA performance, with an RL min of − 40.18 dB at 1.5 mm and 30.55 GHz, and full absorption of frequencies ranging from 18 to 40 GHz was achieved with thicknesses ranging from 1.0 to 5.5 mm. These resins provide new approaches to the development of multifunctional materials demonstrating marine antifouling performance and EMWA properties. [ABSTRACT FROM AUTHOR]

Dy 3+ and Eu 3+ co-doped ZnWO 4 phosphors with different doping concentrations were synthesized by a hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectra. The results showed that the doping concentrations of Eu 3+ could affect the blue and yellow emission intensities of Dy 3+ , and tunable emission color could be obtained by adjusting the doping concentrations of Eu 3+ . Based on the excitation/emission spectra of Dy 3+ /Eu 3+ co-doped ZnWO 4 and the energy levels of Dy 3+ and Eu 3+ , the photoluminescence process in the Dy 3+ /Eu 3+ co-doped ZnWO 4 system was discussed in detail. [ABSTRACT FROM AUTHOR]

• A 3D/2D MOF-derived CoCeO x /g-C 3 N 4 Z-scheme heterojunction was successfully prepared. • CoCeO x /g-C 3 N 4 showed a photocatalytic hydrogen production efficiency of 1050 µmol g−1 h−1. • The synergistic effect of CoCeO x /g-C 3 N 4 and PDS achieved 97% degradation of CBZ within 1 h. • The degradation path and intermediate products were proposed from HRMS analysis and DFT calculations. [Display omitted] A new MOF-derived CoCeOx nanosphere/g-C 3 N 4 nanosheet composite material with a high specific surface area, compact interface, abundant active sites, and promotion of electron transfer and separation was successfully prepared. The prepared 10% CoCeOx/g-C 3 N 4 composite material generated hydrogen with an efficiency of 1050 µmol g−1 h−1 under visible light irradiation, and 97% of carbamazepine was degraded in 1 h at a degradation rate of 0.05 min−1 with the help of PDS. Based on DFT calculations and mass spectrometry analysis, the degradation products and degradation pathways of carbamazepine were also proposed. According to tests of the photocatalytic properties, SO 4 -•, h +,•OH, and •O 2 - were produced by the composite itself; these species play an important role in the degradation. The photocatalytic mechanism was also proposed. The prepared CoCeOx/g-C 3 N 4 composite material provides a simple and effective strategy for energy utilization and wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Ternary Ti–Nb–Zr alloys consisting of biocompatible alloying elements have been prepared to investigate the effect of Zr content on β→α phase transformation, microstructure and mechanical properties. The study showed that element Zr stablized the β phase and that its effect on β phase transus exhibited a “margin effect”. With increasing Zr content, the microstructure of the Ti–Nb–Zr alloy was refined and the strength of ternary Ti–Nb–Zr alloys was also improved while the plasity significantly decreased. The Ti72Nb25Zr3 alloy exhibited the maximum ultimate tensile strengh of 775MPa and Ti73Nb25Zr2 exhibited the lowest elastic modulus of 62GPa. The low elastic modulus of Ti73Nb25Zr2 was attributed to the formation of stress-induced martensite (α″ phase). [Copyright &y& Elsevier]

Rechargeable aqueous zinc ion batteries (AZIBs) have been regarded as an ideal device for the next-generation energy storage system owing to their high theoretical capacity, proper redox potential in aqueous electrolyte, highly abundant, low cost, and high safety. However, growth of zinc dendrites and production of hydrogen gas seriously hinder the practical applications of AZIBs. Herein, a multifunctional protection interface is designed by an in-situ simple method. This interfacial layer is composed of zinc conductor ZnF 2 and zincophilic In-O-F. This hybrid protective layer not only induces uniform zinc deposition and suppresses the hydrogen production, but also inhibits the formation of the by-products Zn 4 SO 4 (OH) 6 ·5H 2 O and the vanadium dissolution. As a result of this synergy effect, the symmetric cell exhibits a long life for 3200 cycles at 20 mA cm−2, as well as a coulombic efficiency (CE) of Zn plating/stripping as high as 99.9 % after 2200 cycles at 2 mA cm−2. The full cells coupled with MnO 2 and V 2 O 3 cathodes also demonstrate excellent electrochemical performances. This work provides a simple and effective way to develop AZIBs. • The treatment process for zinc metal anodes is very simple and easy. • A multifunctional protective layer of In-O-F is formed on the surface of the Zn anode. • The interfacial layer can not only suppress side reactions, but also uniform zinc deposition. • A coulombic efficiency of Zn plating/stripping as high as 99.9 % after 2200 cycles can be achieved. [ABSTRACT FROM AUTHOR]

The composition complexity of Ti(C, N)-based cermets poses a great challenge to the controllability of their sintering process. The effects of both refractory TaC addition and original particle size of starting materials on densification behavior and microstructural evolution of Ti(C, N)-based cermets were investigated during liquid phase sintering. The particle rearrangement only plays a very limited role in promoting densification of Ti(C, N)-based cermets at the initial stage of liquid phase sintering, whereas the pore-filling in the presence of liquid phase becomes a dominant densification mechanism in the middle stage or even earlier. Enhanced densification of ultrafine Ti(C, N)-based cermets is realized by introducing refractory TaC additive based on the grain growth-induced liquid phase pore-filling mechanism, which is also verified by an extended study using other refractory carbide additives such as NbC, ZrC and HfC. This work provides a novel idea for the development of fully densified ultrafine Ti(C, N)-based cermets with outstanding mechanical properties, which are highlighted in machining applications of difficult-to-machine materials as well as other wear-resistant parts operating in high-temperature and high-stress environments. [Display omitted] • The effects of both TaC addition and the particle size of starting materials on the densification behavior of Ti(C, N)-based cermets are clarified. • Enhanced densification of ultrafine Ti(C, N)-based cermets is realized by introducing refractory TaC additive. • This work provides a novel idea for the development of fully densified ultrafine Ti(C, N)-based cermets. [ABSTRACT FROM AUTHOR]

Ultrafine Ti(C, N)-based cermets are vacuum-sintered by refining the particle size of raw materials and tailoring the WC/TaC ratio to achieve the improvements in comprehensive mechanical properties and cutting performance. The hardness, flexural strength and tool lifespan of ultrafine Ti(C, N)-based cermets are substantially higher than those of submicron Ti(C, N)-based cermets with the same composition because of the refined grains and the improved distributions of both metal phases and residual stress. The hardness attenuation behavior and strengthening mechanism in Ti(C, N)-based cermets at different test temperatures have been proposed. At 400 ℃, the hardness attenuation of Ti(C, N)-based cermets depends mainly upon the softening of metal phases. However, at 800 ℃, the hardness attenuation of Ti(C, N)-based cermets is mainly related to the reduced bearing capacity of hard ceramic phases and interfacial sliding. The addition of refractory TaC is beneficial for the improvement of high-temperature mechanical properties and the tool lifespan, attributed to the strengthening of the ceramic framework by tantalum atoms. • The strategy on synergistic refinement of raw powders with various constituents in ultrafine Ti(C, N)-based cermets is proposed for the first time. • The comprehensive properties of ultrafine Ti(C, N)-based cermets are substantially higher than those of submicron Ti(C, N)-based cermets. • The hardness attenuation behavior and strengthening mechanism in Ti(C, N)-based cermets at different test temperatures are proposed. [ABSTRACT FROM AUTHOR]

The pursuit of efficient and stable electrochemical catalysts based on transition metals (TMs) for the hydrogen evolution reaction (HER) is of paramount importance. Herein, a novel partially amorphous NiMoB/NiMoO 4−x catalyst with dense nanoparticle assemblies has been prepared with B doping and reduction by one step NaBH 4 treatment of smooth nanorod-like NiMoO 4 precursor. Benefiting from the MoNi 4 alloys partially reduced from NiMoO 4 precursor, optimized electronic state through B doping and partially amorphous structure, NiMoB/NiMoO 4−x obtained splendid activity for HER with a lower overpotential of 26.2 mV at 10 mA cm 2 coupled with a narrow Tafel slope of 66.75 mV dec 1, in contrast to NiMoO 4 precursor catalyst (260.24 @10 mA cm 2, 149 mV dec 1) in alkaline solution. Additionally, the self-supported NiMoB/NiMoO 4−x electrode exhibits remarkable stability, maintaining a current density of 50 mA cm 2 for a minimum of 40 h attributed to mixed phases of MoNi 4 and amorphous NiMoO 4−x for accelerating the H 2 evolution and enhancing water adsorption. This work offers a facile avenue to rationally design high-performance electrocatalysts for enhancing hydrogen evolution with NaBH 4 accompanying borate doping and reduction. [Display omitted] • Partially amorphous NiMoB/NiMoO 4−x was constructed by one step hydrothermal. • MoNi 4 alloys accelerate H 2 evolution assisted by amorphous NiMoO 4−x. • Oxygen vacancies (O v) can enhance the conductivity and hydrogen spillover effect. • B doping effectively modulates the electronic structure of NiMoB/NiMoO 4−x. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hot corrosion products are different at temperatures ranging from 650 to 950°C. [•] At 650°C, the main corrosion products are AlVO4 and NdVO4. [•] At 750°C, V2O5 reacts with NdMgAl11O19 to form NdVO4, MgV2O6, AlVO4 and alumina. [•] At 850°C, the corrosion products consist of θ-Al2O3, NdVO4 and MgAl2O4. [•] At 950°C, the corrosion products are composed of α-Al2O3, NdVO4 and MgAl2O4. [ABSTRACT FROM AUTHOR]

Abstract: Microstructures and electrochemical characteristics of La0.7Ce0.3Ni3.75− x Mn0.35Al0.15Cu0.75(V0.81Fe0.19) x (x =0–0.20) hydrogen storage alloys have been investigated. X-ray diffraction patterns and Backscatter electron images indicate that La0.7Ce0.3Ni3.75− x Mn0.35Al0.15Cu0.75(V0.81Fe0.19) x alloys consist of a single phase with CaCu5-type structure. The lattice parameter a and cell volume V increase with increasing x value. Maximum discharge capacity monotonically decreases from 320mAh/g (x =0) to 299mAh/g (x =0.20). The high-rate dischargeability at the discharge current density of 1200mA/g first increases from 52.6% (x =0) to 55.6% (x =0.05), and then decreases to 46.7% (x =0.20). Cycling stability first increases with increasing x from 0 to 0.10 and then decreases when x increases to 0.20, which is resulted from the combined effect of the improvement of the pulverization resistance and the decrease of corrosion resistance. [Copyright &y& Elsevier]

Abstract: (Gd1−x Yb x )2Zr2O7 (0≤ x ≤1) solid solutions were prepared by pressureless-sintering process at 1973K to investigate the substitution effect of Yb for Gd on their electrical properties. Electrical conductivity of (Gd1−x Yb x )2Zr2O7 solid solutions were measured using complex impedance spectroscopy from 673 to 1173K over a frequency range of 2Hz to 2MHz in air. (Gd1−x Yb x )2Zr2O7 are oxide-ion conductor in the oxygen partial pressure range from 1.0×10−4 to 1.0atm at all test temperature levels. The measured values of grain conductivity obey the Arrhenius relation. The grain conductivity of (Gd1−x Yb x )2Zr2O7 increases with increasing temperature. However, the grain conductivity of (Gd1−x Yb x )2Zr2O7 gradually decreases with increasing ytterbium content at identical temperature levels. [Copyright &y& Elsevier]

Niobate pentoxides have been considered as promising anode materials of lithium-ion batteries (LIBs) on account of their intrinsic large capacities, high cycling stability and enhanced safety. However, their practical usages are limited by poor rate capabilities due to the low electrical and lithium-ion diffusion rate. In this work, W6+-doped Nb 2 O 5 nano material with enhanced rate capacity was synthesized. W6+ doping can expand crystal lattices in the Nb 2 O 5 , improving Li+ diffusion coefficients. The production of Nb4+ due to W6+ doping results to enhance electrical conductivity. The H 0.05 material (W 0.05 -Nb 2 O 5) exhibits delightful rate capacity (167.1 mAh g−1 at 20 C) and prominent cyclic stability resulting from their structure stability (124.3 mAh g−1 at 5 C after 600 cycles). This novel anode material provides great promise for the construction of high-performance LIBs. • W6+-doped Nb 2 O 5 nano material with enhanced rate capacity was synthesized. • W6+ doping can expand crystal lattices in the Nb 2 O 5 , improving Li+ diffusion coefficients. • Electrical conductivity is enhanced due to the production of Nb4+. • W 0.05 -Nb 2 O 5 exhibits delightful rate capacity (167.1 mAh g−1 at 20 C) and prominent cyclic stability. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) are considered as considerable candidate for electrocatalytic water splitting. The main holdback locates in fabricating well-defined HEAs with moderate electronic structure and uncovering the structural evolution during the reaction process. Herein, we successfully synthesized NiCoFeCrMo HEA-nps by an ultrafast joule heating method for highly efficient oxygen evolution reaction (OER). The optimal graphene incorporated NiCoFeCrMo HEA nanoparticles (HEA-nps) exhibits finely distributed nanoparticles with average size of 17.49 nm and uniformly distribution of all the five elements, which displays the outstanding OER performance with a low onset potential and only requires the 260 mV (vs RHE) to achieve the current density of 10 mA cm−2. X-ray absorption fine structure (XAFS) demonstrates that the high valence Cr and Mo can directly regulate the local structure of HEA-nps, which significantly promoted the intrinsic activity of high active species. This work not only provides a design strategy related to the high valence elements injection for HEAs, but also uncovers the structural evolution of HEAs during OER process. [Display omitted] • NiCoFeCrMo HEA were successfully synthesized by fast Joule heating method. • Multi-electron Cr and Mo elements have regulated the local electronic structure. • The intrinsic mechanism of each element in HEAs during the reaction process has been clarified. [ABSTRACT FROM AUTHOR]

Hygroscopicity is an obstacle to the widespread use of aluminum phosphate binders, but there is still a lack of relevant fundamental research on this topic. Here, the curing behavior, thermal evolution, phase development and hygroscopic behavior of acid aluminum phosphate (AAP) solutions with different P/Al ratios (2.50–4.00) have been systematically investigated. We comprehensively elucidate for the first time the hygroscopic mechanism of AAP and its derived aluminum phosphate, and establish a dynamic relationship between hygroscopic mechanism, moisture absorption rate, microstructure and phase composition. AAP and its derived aluminum phosphate, namely Al(H 2 PO 4) 3 , AlH 2 P 3 O 10 , residual H 3 PO 4 , [HPO 3 ] n and hydroxyl groups are all hygroscopic. The hygroscopic properties of AAP depend on the phase composition, which is determined by the P/Al ratio and the calcination temperature. Due to the formation of Berlinite and Al 8 H 12 (P 2 O 7) 9 , the reduced formation of AlH 2 P 3 O 10 and the absence of H 3 PO 4 , [HPO 3 ] n and hydroxyl groups, the AAP solution with a P/Al< 3.00 and its derived aluminum phosphate exhibit relatively lower hygroscopicity. Meanwhile, increasing the calcination temperature can also improve the hygroscopicity resistance characteristics. This work complements the basic knowledge of AAP systems, especially those with a P/Al< 3.00. This sets the stage for the fabrication of aluminum phosphate binders and aluminum phosphate-based composites with excellent hygroscopicity resistance properties. • The thermal evolution of AAP solutions with different P/Al ratios have been investigated. • The properties of AAP solutions with P/Al< 3.00 have been studied for the first time. • Hygroscopic mechanism of AAP and its derived aluminum phosphate was revealed. [ABSTRACT FROM AUTHOR]

Abstract: X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize Nd x Gd2− x Zr2O7 (x =0, 0.6, 1.0, 1.4, and 2.0) solid solutions pressureless-sintered by using ceramic powders acquired by chemical-coprecipitation and calcination method. Heat capacity measurements were performed with a heat flux-type differential scanning calorimetry in the temperature range of 298.15–1050K. The heat capacity of Nd x Gd2− x Zr2O7 solid solutions increases with increasing the concentration x of neodymium cations from x =0 to x =2.0 at identical temperature levels. At 298.15K, the heat capacities of Nd0.6Gd1.4Zr2O7, NdGdZr2O7 and Nd1.4Gd0.6Zr2O7 are 217, 220 and 224JK−1 mol−1, respectively. Thermodynamic functions such as enthalpy increment, entropy and Gibbs energy functions were calculated from the measured heat capacity data. [Copyright &y& Elsevier]

Abstract: Structural evolution and thermophysical properties of (Sm x Gd1−x )2Zr2O7 (0≤ x ≤1.0) were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-temperature dilatometer and laser flash diffusivity measurements from room temperature to 1400°C. Pure Gd2Zr2O7 ceramics exhibit a defective fluorite-type structure, however, (Sm x Gd1−x )2Zr2O7 (0.1≤ x ≤1.0) ceramics are with a pyrochlore-type structure. The linear thermal expansion coefficients of (Sm x Gd1−x )2Zr2O7 ceramics increase with increasing test temperature. The thermal diffusivities of (Sm x Gd1−x )2Zr2O7 ceramics range from 0.390 to 0.770mm2 s−1, while the thermal conductivities of (Sm x Gd1−x )2Zr2O7 ceramics are located within the range of 1.20 to 1.99Wm−1 K−1 from room temperature to 1400°C. [Copyright &y& Elsevier]

Abstract: The ZrO2–NdO1.5–AlO1.5 ceramics were synthesized by solid-state reaction at 1600°C for 10h in air to fabricate dense bulk ceramics. The relative density, structure and thermal diffusivity of different ZrO2–NdO1.5–AlO1.5 ceramics were investigated by the Archimedes method, X-ray diffraction (XRD), scanning electron microscopy (SEM), laser Raman spectroscopy and laser-flash method. The thermal conductivity was calculated from density, specific heat and thermal diffusivity in a temperature range of room temperature to 1400°C. The Nd2Zr2O7 ceramics doped without alumina only exhibit a pyrochlore-type lattice. The 47.1ZrO2–47.1NdO1.5–5.8AlO1.5 and the 44.2ZrO2–44.2NdO1.5–11.6AlO1.5 ceramics (mol%) consist of both perovskite-like NdAlO3 and pyrochlore structures. However, the 41.3ZrO2–41.3NdO1.5–17.4AlO1.5 ceramics consist of both perovskite-like NdAlO3 and fluorite (F-ZrO2) structures, and the 38.4ZrO2–38.4NdO1.5–23.2AlO1.5 ceramics consist of perovskite-like NdAlO3, F-ZrO2 and hexagonal β-Al2O3-type structures. The thermal conductivities of different ZrO2–NdO1.5–AlO1.5 ceramics increase with the increase of alumina concentration in raw materials under identical temperature conditions. The thermal conductivities of ZrO2–NdO1.5–AlO1.5 ceramics in this investigation were located in the range of 1.50–3.22Wm−1 K−1 from room temperature to 1400°C. [Copyright &y& Elsevier]

• Work function alignment and Fermi-level depinning were realized to obtain ohmic contacts. • The photodetector exhibits fast transient response time and ultrahigh responsivity. • The photodetector eliminates the hysteresis effect causing by ambient air. Two-dimensional molybdenum diselenide (MoSe 2) has attracted immense attention in the field of next-generation optoelectronic devices for its unique structure and excellent photosensitivity. However, the Schottky barrier and surface defects at the interface between the electrode and MoSe 2 channel limit the performance of MoSe 2 photodetectors. Here, using Dirac graphene electrodes, a high performance MoSe 2 photoconductive photodetector was fabricated via mechanical exfoliation. In contrast with photodetectors using Mo/Au electrodes with a high Schottky barrier of 196.7 meV, the devices using graphene electrodes maintain linear ohmic contacts owing to the alignment of the work function and Fermi-level depinning, thereby resulting in fast transient response time on the order of 30 ms and high responsivity exceeding 103 A/W. Moreover, we simultaneously demonstrate the effects of contact resistance on responsivity, response time, and light–dark current ratio of MoSe 2 photodetectors. Further, the hysteresis accompanying the adsorption and desorption of water and oxygen molecules in ambient air was eliminated owing to a high photocurrent level between source and drain. This research unveils the vast potential of proper electrode contact selection to further improve the performance of photodetectors. [ABSTRACT FROM AUTHOR]

• Synthesis of monolayer sulfur-doped graphene film. • Electrical studies of sulfur-doped graphene film. • Typical n-type behavior of sulfur-doped graphene film in air. • High mobility of sulfur-doped graphene film in air. Theoretical calculations demonstrate that sulfur doping is a promising n-type doping method to modulate the electrical properties of graphene. However, as far as we know, the reported sulfur-doped graphene (SG) films have all shown the p-type behavior in air, where doped sulfur atoms have been mainly in the form of thiophene-like S‒C structures. The reason is that thiophene-like S‒C structures as donors cannot fully neutralize the effect of adsorbed oxygen/water molecules as acceptors on the SG film. In this study, the monolayer SG film has been synthesized by the chemical vapor deposition method, where the doped sulfur atoms are mainly in the form of S‒H structures. The electrical studies reveal that the electron concentration of SG film is ~1.1 × 1012 cm−2, indicating the typical n-type behavior in air; moreover, its mobility is as high as ~753 cm2 V−1 s−1, which is obviously higher than those of reported SG films. To the best of our knowledge, it is the first time to obtain the n-type SG film in air. The good performance of n-type SG film can be attributed that S‒H shows a stronger electron donor ability and lower carrier scattering than does thiophene-like S‒C. This study is expected to not only promote the potential applications of SG film, but also benefit the fundamental understanding of effect mechanism of sulfur structures on the properties of SG film. [ABSTRACT FROM AUTHOR]

Hot compression tests of Ti-6Cr-5Mo-5V-4Al alloy were carried out under the temperature range of 963–1113 K and strain rates of 0.001, 0.01, 0.1, 1 s−1 on a Gleeble-3500 isothermal simulator. The strain compensated Arrhenius model (SCAM) was developed after calculating the material constants including α , ln A , n and Q. Also, genetic algorithm (GA) was applied to optimize the material constants according to the acquired material constant ranges and the GA optimized Arrhenius model (GAOAM) was constructed for flow stress prediction. The prediction capabilities of the two models were assessed by correlation coefficient (R) and average absolute relative error (AARE). The results showed that GAOAM was better than SCAM in prediction precise. Two dynamic globularization mechanisms were proposed to describe the dynamic globularization behavior at different strain rate conditions according to the SEM observations. Extrusion type globularization (ETG) occurred at lower strain rate condition and cutting type globularization (CTG) occurred at higher strain rate condition. Also, dynamic globularization occurred easier at lower temperature and the α grain was squashed but not spherized at higher temperature. The processing map based on dynamic materials model was constructed for the microstructure identification. The instability region occurred at the area with high strain rate and low temperature and high η -value region was at the area with low strain rate and high temperature. According to the OM microstructure observations, flow localization occurred at the instability region and the dynamic recrystallization of β grain occurred at the high η -value region. Thus, the microstructure identification ability of the processing map was verified and this processing map could be referred to in the actual production. • The hot compression behavior of the Ti-6554 alloy were studied. • A strain compensated Arrhenius model of Ti-6554 alloy was constructed. • The stress prediction precise of the model was optimized by genetic algorithm. • Two types of dynamic globularization behavior occurred under different conditions. • Microstructure evolution of Ti-6554 alloy was accurately predicted by processing map. [ABSTRACT FROM AUTHOR]

The Li dendrites can penetrate the hard garnet ceramics in the solid-state lithium metal batteries (SSLMBs), severely impairing the cycle life of the battery. Herein, a facile Li/Garnets interface modification strategy is reported to mitigate the adverse effects of Li dendrite penetration, which refers to the insertion of anodized aluminum oxide (AAO) membranes with vertically aligned nanoscale channels at the Li/Garnets interface. As a result, the AAO membranes can confine the deposited Li metal in channels during cycling and induce the Li metal across the channels to continue to depositing uniformly on AAO surface. Furthermore, the deposited Li metal tends to react with AAO to form Li-Al-O compounds, which strengthens the confinement effects to Li metal. The results demonstrate that the full cell with Li/Garnets interface modified by 300 nm aperture AAO exhibits excellent cycling performance, which remain discharge specific of 93.5mAh g−1 (initial: 138.1mAh g−1) after stable operating 716 cycles at 0.2 C. The Li/Li symmetric battery can stably cycle above 1000 h at 0.5 mA cm−2 and 100 h under 1 mA cm−2. This facile method of directly inserting nanoscale vertically aligned network into Li/Garnets interface provides a new approach to promote application of garnets ceramics in SSLMBs. [Display omitted] • The Li/garnet interface was modified by AAO membranes with different pore size. • The Li metal deposition behaviors on AAO membranes. • The effects of pore size of AAO on cycle performance and failure mechanism of full batteries. [ABSTRACT FROM AUTHOR]

Abstract A NbSi 2 /SiO 2 -Nb 2 O 5 multilayer coating, consisting of a NbSi 2 inner layer and a SiO 2 -Nb 2 O 5 outer layer, was prepared on Nb alloy through halide activated pack cementation (HAPC) and microarc oxidation (MAO). The hot corrosion behaviors of the single NbSi 2 coated and the NbSi 2 /SiO 2 -Nb 2 O 5 coated Nb alloys were comparatively investigated with a mixture of Na 2 SO 4 /NaCl (3:1 wt.%) salt at 900 °C. The growth kinetics of the corroded scales follow the parabolic laws, and the parabolic rate constants of the NbSi 2 coated and the NbSi 2 /SiO 2 -Nb 2 O 5 coated specimens were 2.16 × 10−3 mm s−2 and 1.04 × 10−3 mm s−2, respectively. During the corroding process, the SiO 2 -Nb 2 O 5 outer layer that serves as a barrier promotes the formation of continuous SiO 2 scale, and isolates the NbSi 2 layer from the corrosion salt. The lower corrosion rate of the NbSi 2 /SiO 2 -Nb 2 O 5 coated specimens is attributed to the formation of the protective SiO 2 corroded scale. Graphical abstract Image 1 Highlights • A multilayer coating was formed on Nb alloy by HAPC combined with MAO. • The coating consists of a SiO 2 -Nb 2 O 5 ceramic outer layer and a NbSi 2 inner layer. • The coated Nb alloys shows superior hot corrosion resistance due to SiO 2 -Nb 2 O 5 layer. • The superior hot corrosion resistance is due to formation of glassy corroded scale. [ABSTRACT FROM AUTHOR]

Lanthanum-doped titanium-zirconium-molybdenum (La-TZM) alloy with high strength and high toughness was prepared by powder metallurgy and rolling process. The influence of OH − concentrations (5%, 7% and 10%) on the electrochemical behaviors of La-TZM alloys was investigated by potentiodynamic polarization tests. Scanning electron microscopy (SEM) was used to characterize the microstructure and energy dispersive spectroscopy (EDS) was used to analysis the secondary phase. The electrochemical corrosion mechanism was analyzed comprehensively. The results reveal that the corrosion rate of La-TZM alloy first decreases and then increases with the increasing of OH − concentration. The pitting corrosion firstly occurs around the secondary phase particles (La-Ti-Zr-O), and expands along the grain boundaries and defects as the potential increasing. The addition of rare earth element La affects the formation of passive film on the surface and reduces the corrosion resistance of the alloy. The micro galvanic couples between the secondary phase and the matrix accelerate the corrosion of the base material. Therefore, according to the environment, the corrosion resistance and the mechanical properties should be both considered in the process of strengthening alloy with additive elements. [ABSTRACT FROM AUTHOR]

Lanthanum-doped titanium-zirconium-molybdenum (La-TZM) alloys have good mechanical properties, including high strength and toughness due to complex secondary phases. Herein, the formation process of the secondary phases in the La-TZM alloy was revealed by thermodynamics calculations. The ΔG values of possible reactions during sintering were obtained. Results show that the formation process of the secondary phases was controlled by different reactions at different stages. At the first stage (0–500 °C), the main reactions are listed as follows: TiH 2 +O 2 (g)→TiO 2 +H 2 ↑(g), ZrH 2 +O 2 (g)→ZrO 2 +H 2 ↑(g), C 6 H 12 O 6 →[C]+ H 2 O↑, [C]+ O 2 (g)→CO 2 (g)↑, [C]+Mo→MoC, La(NO 3 ) 3 ·6H 2 O→ La 2 O 3 +NO 2 ↑+ NO↑+O 2 ↑+H 2 O; [C]+TiH 2 →TiC + H 2 (g)↑, [C]+ZrH 2 →ZrC + H 2 (g)↑. At the secondary stage (680–960 °C), the dominant reactions include: TiH 2 →Ti + H 2 (g)↑, ZrH 2 →Zr + H 2 (g)↑. At the last stage (≥1200 °C), the primary reaction is Ti + Zr+[O]→ZrTiO 4 . The secondary phases in the La-TZM alloy include TiO 2 , ZrO 2 , ZrC, TiC, MoC, ZrTiO 4, La 2 O 3 and the solid Ti and Zr phases. These results can guide the design of new ingredients for Mo alloys. [ABSTRACT FROM AUTHOR]

An Nb 2 O 5 -SiO 2 -Al 2 O 3 /NbSi 2 /Nb 5 Si 3 multilayer coating is fabricated by a two-step method of pack cementation and microarc oxidation. The isothermal oxidation resistances of Nb 2 O 5 -SiO 2 -Al 2 O 3 /NbSi 2 /Nb 5 Si 3 multilayer coated and NbSi 2 /Nb 5 Si 3 coated Nb alloy are investigated at 1250 °C. The results show that the oxidation kinetics of NbSi 2 /Nb 5 Si 3 coated Nb alloy follows a parabolic-like law with the parabolic rate constant k p of 0.79 mg 2  cm −4 h −1 . Whereas the multilayer coated Nb alloy exhibits better oxidation resistance with a lower k p of 0.06 mg 2  cm −4 h −1 for the first 15 h oxidation period, and a comparable oxidation resistance to that of NbSi 2 /Nb 5 Si 3 coated Nb alloy in the following oxidation period. The multilayer coating has successfully retarded the oxidation process, which is attributed to the formation of Al 2 O 3 and glassy SiO 2 within the Nb 2 O 5 -SiO 2 -Al 2 O 3 outer layer. [ABSTRACT FROM AUTHOR]

Ni-rich cathode materials always suffer from serious side reaction and irreversible phase transition leading to capacity fading and thermal instability, which could be improved by surface coating and elemental doping. However, it is difficult and cumbersome to carry on the coating and doping at the same time. Herein, a facile method of bi-functional Ti modification has been employed on LiNi 0.8 Co 0.15 Al 0.05 O 2 to enhance surface and structural stability via heterogeneous layer coating and bulk doping. The mechanism and synergistic effect of Ti modification has been investigated by XRD, XPS, SEM, TEM and the half-cell test in details. The existence of Ti occupancy in Ni site of the transition metal layer has been confirmed. Besides, a 22 nm heterogeneous layer has been detected on the particle surface and the composition has been analyzed. Ti bulk doping can reduce the cation mixing degree, and stabilize the lattice due to the pillar effect and charge compensation. Moreover, the heterogeneous coating layer could protect the cathode particles from hydrofluoric acid attack and reduce the decomposition of electrolyte during cycling. With the synergistic effects of heterogeneous layer coating and bulk doping, NCA-T2 exhibits the highest initial capacities of 162.9 and 182.4 mAh·g −1 at 1C and 0.1C, and the discharge capacity retentions of 1C cycling reach 85.0% after 200 cycles. [ABSTRACT FROM AUTHOR]

The electrochemical corrosion behaviors of as-SLMed CoCrW alloy after different heat treatments were investigated in 0.9% NaCl solution with and without the fluoride ions by open circuit potential (OCP), potentiodynamic polarization, electrochemical impedance measurements (EIS). The results showed that the SLMed CoCrW with a homogeneous structure experienced heat treated at 1150 °C followed by water quenching exhibited the better corrosion resistance to the electrolyte, whereas the alloy heat treated at 1150 °C followed by furnace cooling with a large amount of continuous blocky precipitates was susceptible to the corrosion. The XPS results indicated that the fluoride ions addition promoted the absorption of F − , Cl − and Na + on the passive film. The fluoride ions slightly accelerated the corrosion of the SLMed CoCrW alloy by changing the composition of the passive film, thereby reducing the protectiveness of the film. Accordingly, a corrosion mechanism associated with the fluoride ion to the as-SLMed CoCrW alloy was proposed herein. [ABSTRACT FROM AUTHOR]

The application of Ni-rich ternary cathode materials is restricted by the irreversible phase transition and interfacial side reactions during long-term cycling. Herein, a LiTaO 3 coating and Ta5+ doping strategy are simultaneously achieved by a simple solid-phase synthesis. The surface side-reaction and undesired phase transition of LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) are effectively restrained by this approach, which utilizes residual lithium to afford the coating. The NCA-LTO 3 (The modified NCA with a LiTaO 3 coating content of 3 wt%) delivers a high reversible capacity of 168.04 at 5 C (140.56 mAh g−1 for NCA), revealing the enhanced rate capability. More importantly, the cycling life could be greatly maintained after 200 cycles with a significant capacity retention of 94.1% (61.2% for NCA) at 1 C. Mechanism analysis indicates that such improvement is ascribed to the coating of conductor LiTaO 3 and doping Ta5+ greatly promoting the Li-ion diffusion and stabilizing the interface of NCA. The study proposes a highly convenient strategy for interfacial optimization of cathode materials toward assisting the large-scale production of high-performance NCA. • The double modification of coating and doping is realized by consuming the residual lithium salt on the surface of NCA material. • After LiTaO 3 coating and Ta5+ doping, the discharge capacity, cycling stability and rate performance are significantly improved. • The double modification improves the structural stability of LiNi 0.8 Co 0.15 Al 0.05 O 2. [ABSTRACT FROM AUTHOR]

Molybdenum powders were high-energy ball milled for 3, 6, 9 and 12 h respectively, using two ball milling methods: (1) dry milled in vacuum and (2) wet milled in mixed solution of ethanol-polyethylene glycol. The effect of high-energy ball milling on relative density of titanium-zirconium-molybdenum (TZM) alloy was investigated. Particle size distribution and calculated proportion in each size range were designed according to the Dinger-Funk model, reaching the dense packing state. The effects of three different kinds of carbon source (graphite, stearic acid (C 18 H 36 O 2 ) and carbon nanotubes (CNTs)) on oxygen content and relative density were analyzed. The effects of carbon source on oxygen content were studied. After high-energy milling, fine molybdenum alloy powder particles and large amounts of dislocations and vacancies are helpful to improve TZM alloy density during solid sintering process. Doping carbon nanotubes (CNTs) into the TZM alloy as carbon source can improve its density and decrease oxygen content, which is more effective than graphite or stearic acid as carbon sources. Higher TZM alloy relative density results in lower oxygen content. [ABSTRACT FROM AUTHOR]

Titanium-Zirconium-Molybdenum alloy and Lanthanum-doped Titanium-Zirconium-Molybdenum alloy were fabricated by powder metallurgy method. The effect of lanthanum in arc erosion of titanium-zirconium-molybdenum alloy was investigated by using SEM, arc erosion test system and analytical balance. Results show that lanthanum-doped Titanium-Zirconium-Molybdenum alloy has a higher strength, density and lower electrical resistivity compared to that of Titanium-Zirconium-Molybdenum alloy. The average of arc energy and the arc time decrease 17.9% and 20.9% respectively because doping lanthanum decreases the arc current by forming reverse current between the contacts. The mass loss decreases 32.5% and erosion area reduces 32.6%. The lanthanum in the cathode has a good ability of electron emission. [ABSTRACT FROM AUTHOR]

The mixture of 5 wt% LaB 6 and mechanically alloyed Si-B-C-N powders was conventionally ball-milled and then compacted by spark plasma sintering at 1250–2000 °C and 50 MPa. Densification, microstructural evolution and mechanical properties of the as-prepared La/Si-B-C-N monoliths were investigated. At 1360 °C, sintering initiates coupled with rapid densification caused by particle rearrangement and plastic deformation. Grain-boundary sliding and atomic diffusion lead to further densification when sintering continues. Only SiC and La-containing BN(C) phases are detected in La/Si-B-C-N monoliths sintered at temperatures higher than 1900 °C. The monoliths sintered at 2000 °C show a high fracture toughness (4.6 MPa m −1/2 ) attributed mainly to lamellar La-containing BN(C) grains. [ABSTRACT FROM AUTHOR]

To improve the electrochemical performance of silicon-based anode, silicon/carbon (Si/C) material was synthesized via dopamine polymerization process and subsequent pyrolysis. The carbonized polydopamine (PDA-C) is N-doped, which improves the electronic conductivity of material and helps lithium ion transmission. The existence of polydopamine-derived carbon is evidenced by X-ray photoelectron spectroscopy and scanning electron microscopy. Electrochemical characterizations confirms that the composite with PDA-C layer exhibits initial reversible specific capacity of 741.2 mAh g −1 with an initial coulombic efficiency of 78.1% at current density of 300 mA g −1 . A high capacity of 611.3 mAh g −1 can be delivered for composite with PDA-C layer after 100 cycles at a current density of 300 mA g −1 . The rate capability is also enhanced, delivering reversible capacity of 704.3, 611.4, 529.3, 480.3 mAh g −1 at current densities of 1, 2, 3, 4 A g −1 . [ABSTRACT FROM AUTHOR]

Pure h-BN ceramics were processed at different sintering temperatures and hold times using ball milled nanocrystalline or amorphous h-BN powders. Increases in sintering temperature induced greater grain growth but reduced relative densities and mechanical properties. Changes in sintering hold times caused further increases in grain sizes and relative density, but had little impact on mechanical properties. The grain sizes play an important aspect of strength in h-BN ceramics. The relationship of flexural strength and grain sizes in h-BN ceramics conforms to Hall-Petch behavior. When the grain size of h-BN ceramics increased from 0.3 μm to 8 μm, the flexural strength declined from 163 ± 6 to 84 ± 4 MPa. The mechanical properties of h-BN ceramics depend both on relative densities and grain sizes. [ABSTRACT FROM AUTHOR]

The quenching expansion tests in the temperature range 350–500 ℃ and isothermal compression tests in the range 350–500 ℃ & 0.01–10 s−1 of a homogenized Al-Cu-Li alloy were conducted to investigate the flow behavior and thermal expansion behavior. The corresponding microstructures of the tested specimens were characterized by back-scattered electron-scanning electron microscope (BSE-SEM), electron back-scattered diffraction (EBSD) and transmission electron microscope (TEM). Coarse secondary phases including Al 2 CuLi (T 1), Al 2 (Cu-Ag)(Li-Mg) (Ω), Al 2 Cu (θ), Al 2 CuMg (S) dissolve with increasing temperature, which is likely to increase the coefficient of thermal expansion. The temperature rising induced by deformation heat varies from 2.29 ℃ to 38.32 ℃ with increasing strain rate and decreasing temperature. Three different constitutive models were calculated, evaluated and optimized, based on which, the two-step optimized Johnson-Cook model showed the highest precision. At the temperature ≤ 400 ℃, the existences of undeformable coarse phases (especially T 1 or Ω phase) promote particle stimulated nucleation (PSN), which pronouncedly increases the volume fraction of dynamic recrystallization (DRX) and decreases the flow stress. At temperature of 450 ℃, most of undeformable coarse phases dissolved, cutting-off mechanism of S and θ phase was observed, which is no longer beneficial to PSN, and CDRX becomes the main DRX mechanism. • Flow behavior and hot expansion behavior of the homogenized Al-Cu-Li alloy were analyzed. • Microstructures before and after compression at high temperature of the homogenized Al-Cu-Li alloy were compared. • A novel two-step optimized Johnson-Cook model with high prediction precision was proposed. • Cut-off mechanism of Al 2 CuMg phase during deformation were identified. • PSN and CDRX were characterized and the effects of precipitates on them were discussed. [ABSTRACT FROM AUTHOR]

Novel refractory carbide reinforced tungsten matrix (W-MeC) composites have high microstructural stability and attractive high-temperature mechanical, thermo-physical and chemical properties, and they are promising candidates for a very wide range of applications across the aerospace, military, advanced machining and energy industries. In this review, material design, fabrication methods and microstructural features of W-MeC composites are presented. The mechanical and thermo-physical properties, resistance to oxidation, thermal shock and ablation, and the mechanisms of high-temperature strengthening of W-MeC composites are covered. In addition, the applications of W-ZrC composites as well as major challenges and future trends are outlined as well. This review provides a good understanding of the state-of-the-art research in W-MeC composites and inspires researchers to explore and develop W-MeC composites with improved properties fabricated in smart and cost-effective manners. [Display omitted] • The state-of-the-art research in W-MeC composites is reviewed. • Material design, fabrication methods, microstructures, properties and applications of W-MeC composites are presented. • Major challenges and future trends of W-MeC composites are put forward. [ABSTRACT FROM AUTHOR]

Modified spherical graphite/silicon/flake graphite/disordered carbon (SG/Si/C) composite is successfully synthesized by using nano-silicon, flake graphite (FG), modified spherical graphite (SG) and citric acid as raw materials via liquid solidification and subsequent pyrolysis. The material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and electrochemical measurement. The morphology observation shows a core–shell structure with silicon/carbon material as the shell and SG particles as the core. SG/Si/C composites display a good cycle performance with capacity retention of 86% after 50 cycles under a current density of 100 mA g −1 , and also exhibit an excellent cycling performance at higher current densities of 200 mA g −1 and 300 mA g −1 . The available raw materials availability and simple synthesis process promote the as-prepared SG/Si/C materials a promising anode for commercial use. [ABSTRACT FROM AUTHOR]

(La 1− x Er x ) 2 Zr 2 O 7 ( x = 0, 0.025, 0.05, 0.075, 0.1) nanocrystals have been successfully prepared by the chemical co-precipitation and calcination method, and were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. The nanocrystals calcined at 800 °C for 5 h exhibit good crystallinity and have a particle size of about 25 nm. The emission band centered at 528 nm is identified as the 2 H 11/2 → 4 I 15/2 transition, the emission bands centered at 550 nm and 562 nm are attributed to the 4 S 3/2 → 4 I 15/2 transition, and the emission bands centered at 663 nm and 682 nm are ascribed to the 4 F 9/2 → 4 I 15/2 transition. The emission intensity increases with increasing Er 3+ content, up to a critical concentration between x = 0.025 and x = 0.05, and then decreases with further increasing Er 3+ concentration. [ABSTRACT FROM AUTHOR]

Microarc oxidation (MAO) coatings have been formed on Ti 2 AlNb alloy in different electrolytes containing NaAlO 2 , Na 2 SiO 3 and (NaPO 3 ) 6 solutions, respectively, to evaluate their phase constituents and high temperature oxidation resistance at 800 °C. The electrolyte compositions have a significant influence on structure and oxidation resistance of MAO coatings on Ti 2 AlNb alloy. MAO coatings formed in the electrolytes of NaAlO 2 and (NaPO 3 ) 6 solutions, respectively, have a better oxidation resistance than the bared Ti 2 AlNb alloy after oxidation at 800 °C up to 150 h. However, the situation is reversed for the MAO coatings formed in a Na 2 SiO 3 electrolyte, which has a similar weight gain to the bared Ti 2 AlNb alloy. A compact oxide barrier interlayer of Ti- and Al-containing oxides is found between the substrate and the MAO coatings formed in the NaAlO 2 solution, which is effective to protect Ti 2 AlNb alloy from the inward diffusion of oxygen and the outward diffusion of metallic elements. [ABSTRACT FROM AUTHOR]

Sm 2 Zr 2 O 7 and (Sm 2/3 Yb 1/3 ) 2 Zr 2 O 7 feedstocks prepared by spray drying have been used to produce ceramic thermal barrier coatings. Double-ceramic-layer thermal barrier coatings with an under-layer of 8 wt.% yttria-stabilized zirconia (YSZ) and a top-layer of Sm 2 Zr 2 O 7 or (Sm 2/3 Yb 1/3 ) 2 Zr 2 O 7 were deposited by plasma spraying. Plasma sprayed Sm 2 Zr 2 O 7 coatings are composed of a pyrochlore-type phase and a t -ZrO 2 phase, while (Sm 2/3 Yb 1/3 ) 2 Zr 2 O 7 coatings exhibit a defect fluorite-type structure. The number of thermal shock failure at 1250 °C is 52 and 33 for Sm 2 Zr 2 O 7 /YSZ and (Sm 2/3 Yb 1/3 ) 2 Zr 2 O 7 /YSZ coatings, respectively. The thermal shock failure of zirconates/YSZ double-ceramic-layer coatings mainly occurs inside ceramic layers, and is not caused by the thermal grown oxide layer from the bond coat. [ABSTRACT FROM AUTHOR]

• Decomposition of urea can facilitate the nucleation of 5 nm size SnO 2 particles. • Urea can prevent MXenes from oxidation during hydrothermal process. • Interaction between SnO 2 particles and MXenes is proved by XPS. • SnO 2 /MXenes shows a raise of capacity and reaches 904 mA h g−1 at 1000th cycles. [Display omitted] Commercial graphite anodes show limited capacity in lithium-ion batteries, which inhibits the development of high-energy and high-power devices. Although the theoretical capacity of SnO 2 based anodes is three times higher than that of graphite, their practical application is hindered by the poor cycling stability. In this study, we report a ball-milling assisted exfoliation method for the scalable production of delaminated MXene nanosheets, followed by the preparation of 5 nm SnO 2 nanocrystals anchored on MXene nanosheets through a hydrothermal reaction. SnO 2 /MXenes nanocomposites exhibit long cycling life up to 1000 cycles with a high capacity of 904 mA h g−1, which can be ascribed to the high conductivity of the MXene substrates, and the anchoring effect between SnO 2 nanoparticles and MXene sheets that can prevent crystal aggregation or collapse during cycling. [ABSTRACT FROM AUTHOR]

In order to improve the welding performance of WC–Co to steel, a multilayer functionally graded (WC–Co)–Ni composite (MFGWC) was successfully fabricated by sintering the multilayer green compact, and a Ni-rich layer was covered on the compact surface. The microstructure, composition and micro-hardness of the MFGWC were investigated in this paper, results showed that the MFGWC was composed of WC–Co substrate, multi-transitional layers and pure Ni layer. The key part, multi-transitional layers formed between Ni layer and WC–Co substrate, was obtained successfully. The micro-hardness of the composite gradually decreased from 1300 HV to 66 HV along the direction of WC–Co substrate to pure Ni layer, this was due to a decrease in the amount of WC particles and the corresponding increase of Ni phases. The multi-transitional layer played a role in reducing the residual stresses that were induced by the difference of thermal expansion between WC–Co substrate and steel. [ABSTRACT FROM AUTHOR]

The effects of a single additive (SnO 2 , Ta 2 O 5 , or WO 3 ) on the crystal structure, densification, and electrical conductivity of the GdSmZr 2 O 7 ceramic have been examined. The GdSmZr 2 O 7 ceramic with or without a single additive of 1 wt.% SnO 2 , Ta 2 O 5 , or WO 3 sintered at temperatures between 1773 and 1973 K exhibits a single cubic pyrochlore-type phase. The relative densities of different compositions increase with increasing sintering temperature. The total conductivity of different samples obeys the Arrhenius relation. The total conductivity of the GdSmZr 2 O 7 ceramic is not improved by the addition of 1 wt.% SnO 2 , Ta 2 O 5 , or WO 3 . A single additive, SnO 2 , Ta 2 O 5 , or WO 3 , is not an effective sintering aid for the GdSmZr 2 O 7 ceramic. [ABSTRACT FROM AUTHOR]

Stoichiometric amorphous In2Se3 films were deposited on the soda lime glass substrates at temperatures ranging from 160 to 250 °C. Counterparts of amorphous In2Se3 films vary with the increase of substrate temperature. The resulting structure of the annealed films is influenced by the deposition condition. It is observed that there is a "threshold" deposition temperature of 220 °C and Na doping stabilizes a metastable phase (κ-In2Se3) at room temperature. Furthermore, the optical property of these films was analyzed. The results allow us to optimize the preparation method of γ-In2Se3 thin films. [ABSTRACT FROM AUTHOR]