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The heating of high-Ni cathode materials under low O2 partial pressures has generally been considered undesirable. Contrary to this general understanding, this study reports the postheating of LiNi...

Detection of a trace amount of NO2 at room temperature has very important applications in air quality monitoring, protection of human health and medical diagnose. However, the existing NO2 sensors often suffer from low sensitivity when the concentration at the ppb-level. Here, we report a new kind of materials based on graphdiyne(GDY) for highly sensitive detection of ppb-level(ppb: part per billion) NO2 at room temperature. After thermal treatment of the as-prepared GDY at 600 °C under argon atmosphere for 2 h(the obtained sample denoted as GDY-600), the prepared sensor with GDY-600 displays excellent sensitivity with a response value of 6.2% towards 250 ppb NO2 at room temperature, which is better than most of reported sensing materials. In addition, the sensor exhibits significantly high selectivity to NO2 against typical interfering gases including CO, CO2, NH3, H2, H2S and toluene. Moreover, the sensor shows remarkable stability after repetitive measurements. The superior sensing performance of GDY-600 can be ascribed to the highly π-conjugated structure with special acetylenic bonds and abundant oxygen-containing functional groups, which are all beneficial for the gas adsorption and redox reaction on the surface.

A technique is developed and new composite materials containing manganese oxides MnxOy (x = 1, 2, 3; y = 2, 3, 4) are synthesized based on high-silica nanoporous glasses (NPGs). The synthesis is carried out by successive impregnation of porous glass plates in aqueous solutions of manganese chloride (MnCl2) and oxalic acid (H2C2O4), followed by heat treatment of the samples in an argon atmosphere to decompose the reaction product (MnC2O4). The chemical composition and phase composition of the obtained composites are investigated.

Electropulsing treatment was imposed on SUS303 free-cutting steels to analyze the evolution of MnS inclusions. SUS303 steels were treated in argon atmosphere under various conditions: before the formation of MnS inclusions (1773 K), at the beginning of the formation of MnS inclusions (1678 K), and after the formation and growth of MnS inclusions (1583 K). The results show that the sizes of globular MnS inclusions decrease with an increase of current density when the electropulsing treatment is treated in the melting stage. Meanwhile, electropulsing treatment restrains the growth of inclusions due to the different conductivities between the molten steel and MnS inclusions when electropulsing treatment is treated in the solidification process. However, the number of fine rodlike MnS inclusions increases with the increase of current density in the samples treated in the inclusion nucleation stage and solidification stage because the reduction in chemical potential produced by electropulsing treatment will require less undercooling. Experimental data demonstrate that the application of electropulsing treatment is a fantastic new method to control the morphology and size of MnS inclusions in the melting stage.

The electrical explosion method, due to its simplicity and high efficiency, has attracted significant attention in graphene synthesis. Generally, graphite rods and carbon fibers are used to form graphene by electrical explosions in a liquid medium. In the present work, the preparation of graphene from graphite powder in a tube by electrical explosions was proposed. A certain amount of graphite powder was confined in a tube and electrically exploded in an argon atmosphere. The diameter of the constraint tube affected the microstructure of the as-prepared products (graphite nanosheets and few-layer graphene) under the charging voltage of 14 kV. When the diameter of the constraint tube was 3 mm, explosive products were mainly composed of few-layer graphene. The collision degree between graphite powder particles and the diameter of the constraint tube were the key factors to form graphene by electrical explosions. The underlying mechanism governing the generation of graphene was carefully illustrated. Moreover, a self-designed device for electrical explosions was developed.

Experimental data on the effect of the ambient atmosphere (a vacuum or argon) on the phase composition of silicon carbide fibers formed upon the siliconization of carbon felt are presented. The major phases produced in the siliconization of carbon felt are β-SiC (3C) in vacuo and α-SiC (6H) in the argon atmosphere. When carbon felt is siliconized in vacuo, residual silicon is present on the surface of the silicon carbide felt fibers. The ambient atmosphere determines the nature of the siliconization process at 1650°C: in vacuo, SiC is formed due to the reaction of carbon fibers with the silicon melt wetting them, while in argon, it is formed due mainly to the reaction with vaporous silicon.

The current research investigates the kinetics of non-isothermal and isothermal pyrolysis of three different coal types (with different ash content) using the thermogravimetric (TGA) method in an argon atmosphere. The effect of mineral matter content on the pyrolysis characteristics was presented within the temperature range 600–1000 °C. The high ash coal sample used in the present study was collected from Talcher region, Orissa State, India. The coal sample was divided into three fractions (1.4, 1.6, 1.8) using the density separation technique to examine the effect of mineral matter or ash content on the coal pyrolysis during isothermal and non-isothermal heating. The results in the current study show that the mineral matter content helps in aiding the devolatilization rates in the pyrolysis process. Compared to the other coals, the 1.8 coal with a high ash content shows the maximum mass loss rate in the devolatilization range. The mass loss rate for the 1.4, 1.6, and 1.8 coals is found to be 1.2 μg/min, 1.2 μg/min, and 1.7 μg/min respectively. In isothermal conditions, the activation energies for 1.4, 1.6, and 1.8 is found to be 4.49 kJ/mol, 4.58 kJ/mol, and 12.5 kJ/mol, respectively.

316L based stainless steel hollow fiber membranes (HFs) are used as an alternative for polymer and ceramic based membranes. Application areas of 316L hollow fiber membranes are applications such as support or particle filter of gas and liquid separations in chemical and waste treatment industries. Among various methods, dry-wet spinning technique was selected as the production method of hollow fiber membranes since it is the most popular one. The aim of the study is to produce hollow fiber membranes in different powder particle sizes (coarse, fine, and their mixture), and to examine their structure and also their properties such as chemical compositions, pore amount, average pore size, and pore distribution. 3-point bending tests were also used to determine their mechanical properties. HFs produced from fine particles show higher densification than coarse particle size samples. In terms of pore structure, mixed particle size yields lower porosity and pore size than the finest particle size. On the other hand, the finest particle size yields the highest bending strength and bending deflection.

In this study, the phase transformations of steelmaking slags were identified for the purpose of phosphorus separation and material recycling, where the samples after high-temperature experiments and quenching were characterized using electron probe x-ray microanalysis and x-ray diffraction. For hot slags held under argon atmosphere, the main phases changed from (Fe,Mg)O, (Fe,Ca)O and C2S-C3P (Ca2SiO4-Ca3P2O8) at 1450–1400°C to (Fe,Mg,Ca)O, C2S-C3P and CaO-TiO2-FeO-Al2O3 liquid at 1200–600°C. From the respect of phosphorus concentration in C2S-C3P, 1400°C was an optimum temperature, which also accounted for a suitable treatment temperature for cooled slags. Moreover, air atmosphere resulted in more liquid phase, CaO-MgO-Fe2O3-SiO2, due to the oxidation of Fe2+ to Fe3+. In addition to C2S-C3P, P2O5 was also present in this liquid phase, a drawback for further phosphorus recovery. The P2O5 concentration in the liquid phase decreased with decreasing temperature, and thus, a relatively lower temperature was preferred in air.

The mechanosynthesis process of composite powders for the preparation of a TiB2-20 wt pct MoSi2 composite material from reaction mixtures Ti + B + Mo + Si and Ti + B + MoSi2 in an argon atmosphere has been investigated. Synthesis proceeds according to mechanically stimulated reactions, and, in both cases, ultradisperse composite powders, along with the main phases, contain traces of lower silicides. The mathematical modeling of the distribution of interparticle contacts in the mixtures during solid-phase interaction has revealed a good agreement between the calculated and experimental data of mechanosynthesis. Spark plasma sintering in nonlinear regimes with a sequential increase in the sintering pressure from 6 MPa up to 50 MPa, accompanied by a decrease in the heating rate from 150 °C/min down to 50 °C/min, enables us to reduce the sintering temperature down to 1550 °C and obtain a dense composite with a mean size of TiB2 grains of about 200 nm. The TiB2-20 wt pct MoSi2 composite sintered at 1550 °C surpasses the composite sintered at 1750 °C in Vickers hardness (27.5 ± 3.2 GPa and 24.6 ± 2.2 GPa, respectively) but ranks below it in bending strength (480 ± 32 MPa and 571 ± 24 MPa, respectively).

In this study, phase formation, the microstructure and the thermal properties of an Al-Mg alloy solidified at high temperature in the argon atmosphere were investigated. The maximum formation of a single-phase Al-Mg alloy was determined by the ratio of the primary aluminum and magnesium components Al – 50 at.% Mg and argon gas flow at a temperature of 750 oC. After solidification at pressures of 1 MPa and 2 MPa, the main phases are the β and γ phases of Al-Mg alloy, in equilibrium condition. The thermal properties of the Al-Mg alloy were studied using DTA-TG (Tmelting = 458.4 oC, Тoxidation= 568.4 and 616.9 oC oxidation of pure Mg and pure Al, respectively).

To develop an effective method for removing sulfur from spent refining slag at high temperature, the slag was treated in argon atmosphere using desulfurization ash as desulfurization reagent. Experimental results revealed that at 1773 K, molar ratio of CaS to CaSO4 + CaSO3 of 3:1, and reaction time of 2 hours, sulfur removal efficiency reached a maximum of 67.9 pct. The optimal ratio indicates the reaction of CaS and CaSO4 + CaSO3 to generate S2 may predominante during processing.

The experiments were carried out to determine the vacuum-plasma characteristics (mainly erosion and outgassing rate in a vacuum) of the stainless steel 12X18H10T before and after processing the walls of the vacuum chamber with the glow discharge and combined, glow-microwave plasma discharges in argon atmosphere. The current-voltage characteristics, the electron density and electron temperature were measured. It was observed that the discharge voltage in the combined regime is significantly lower than in glow discharges. In some modes, this voltage decrease can be up to 200 V. It was shown that erosion of stainless steel 12X18H10T in the combined discharges is 70 %, less than in the glow discharges. Measurements were made of the outgassing rate of 12X18H10T stainless steel with the thermal desorption probe in situ in the DSM-1 vacuum chamber. It was shown that cleaning the chamber wall by the glow discharge during 5 h leads to a decrease in the outgassing rate from 5.5·10-5 to 1·10-5 (Torr.l)/(s.cm2) . When the chamber wall is treated with GM discharge starting from nearly the same initial conditions the outgassing rate decreased to 3·10-6 (Torr.l)/(s.cm2). Spectral measurements of the plasma radiation of a glow and combined discharges show a decrease in the ratio of the peaks of argon ions and neutrals during the transition from a glow discharge to a combined one.

This work proposed a novel double-bath-type sonoreactor to demonstrate the possibility of applying ultrasound power for simultaneous production of gaseous fuels with degradation of Rhodamine B (RhB). The developed double-bath-type sonoreactor allows concentrating the energy of the ultrasonic waves to a limited region and, consequently allows the acoustic intensity in there to be increased approximately 30-fold compared to that can be created in a normal ultrasonic bath at the same applied power. The effect of acoustic intensity, temperature of water bath, static and bubbling argon atmosphere, initial RhB concentration, and dissolved gases on the sonochemical activity both in terms of RhB degradation and gaseous fuel productions were fully investigated. The possible pathways for the simultaneous production of gaseous fuels with degradation of RhB were elucidated. Sonochemical degradation of RhB was successfully analysed by Langmuir-Hinshelwood-type kinetics.

This paper reports the emission characteristics of leaf and wood biochar (LC500 and WC500) pyrolysis in a drop tube furnace at 1300 °C in argon atmosphere. The char yields at 1300 °C are ∼ 65% and ∼ 73% respectively for LC500 and WC500. Over 60% Mg, Ca, S, Al, Fe and Si are retained in char after pyrolysis at 1300 °C. The retentions of Na and K in the char from LC500 pyrolysis are lower than those in the char from WC500 pyrolysis due to release via enhanced chlorination as a result of much higher Cl content in LC500. Particulate matter (PM) with aerodynamic diameter of

The effects of milling time on the structural and morphological features of Si-based refractory compounds (SBRC) derived from selected agro-wastes (bamboo leaves- BL and coconut shell-CS) are reported. The processing of the SBRC was done using the controlled environment of a conventional furnace at a heating rate of 10°/min between 900 and 1650 °C. The SBRC was then placed in 250 ml vial containing zirconia balls as grinding media of 8 mm in diameter to mill in an argon atmosphere (ultra-pure with 99.98% wt

A new high-entropy monoboride (Mo0.2Ta0.2Ni0.2Cr0.2W0.2)B ceramic with a WB-type orthogonal structure was designed and synthesised by in-situ reactive hot pressing at 2000 °C and 30 MPa for 1.5 h under an argon atmosphere. The microstructure of the sintered samples was comprehensively characterised, and the formation of a high-entropy monoboride (Mo0.2Ta0.2Ni0.2Cr0.2W0.2)B ceramic was confirmed. Owing to the high density of the dislocations and strengthening metal-boron bonds, the high-entropy (Mo0.2Ta0.2Ni0.2Cr0.2W0.2)B ceramic exhibited a hardness of 48.51 ± 4.07 GPa, which enabled it to be classed as a new superhard material. In addition, the thermal conductivity (2.05 ± 0.10 W/(m·K) at 400 °C) and electric conductivity (132.30 S/cm) were determined.

En este trabajo reportamos el estudio de las propiedades magnéticas y estructurales del sistema Fe90Al10 obtenidas por Aleamiento Mecánico (AM), para la fabricación de blancos (target) que se usarán para producir películas delgadas por sputtering. Las muestras en forma de polvo se prepararon utilizando la técnica de aleamiento mecánico con una relación de masa bolas / masa muestra, de 10:1, en atmosfera de argón con bolas de acero inoxidable y jarras del mismo material, y con 48 y 72 horas de molienda. La caracterización magnética y estructural se realizó por Espectroscopia Mössbauer (MS), Magnetometría de muestra Vibrante (VSM) y Difracción de Rayos-X (XRD). Los espectro Mössbauer de los polvos se ajustaron con una componente ferromagnética correspondiente a tres sitios ferromagnéticos mostrando un campo hiperfino medio de 29,1 T para las muestras con 48 horas de molienda y de 25,4 T para las muestras con 72 horas de molienda.El refinamiento de los patrones de XRD presenta en todos los difractogramas picos de la fase FeAl - BCC con parámetros de red 2,886 Å y 2,889 Å para la molienda de 48 y 72 horas respectivamente. Los ciclos de histéresis del sistema Fe90Al10 en estudio evidencian que es un material magnéticamente blando. In this work we report the study of the magnetic and structural properties of the Fe90Al10 system obtained by mechanical alloying, for the manufacture of targets that will be used to produce thin films by sputtering. Samples in powder form were prepared using the Mechanical Alloying technique with a mass ratio of balls / sample mass, of 10: 1, in an argon atmosphere with stainless steel balls and jugs of the same material, and with 48 and 72 milling hours. Magnetic and structural characterization was performed by Mössbauer Spectroscopy (MS), Vibrating Sample Magnetometry (VSM) and X-Ray Diffraction (XRD). The Mössbauer spectrum of the powders was adjusted with a ferromagnetic component corresponding to three ferromagnetic sites showing an average hyperfine field of 29.1 T for the samples with 48 hours of milling and 25.4 T for the samples with 72 hours of milling The refinement of the XRD patterns was performed using the Rietveld method by means of the GSAS program showing in all diffractograms the FeAl-BCC phase with lattice parameters 2.886 Å and 2.889 Å for the milling of 48 and 72 hours respectively. The hysteresis cycles of the Fe90Al10 system under study show that it is a magnetically soft material.

TiB2-SiC and TiB2-SiC-graphene nanoplatelets (GNPs) composites were prepared using field-assisted sintering technology at 2100 °C in argon atmosphere, and the influence of the SiC and different GNPs addition on microstructure development, mechanical and tribological properties has been investigated. Instrumented hardness, bending strength, chevron-notched fracture toughness and ball-on-flat tribological tests were used for the testing and characterization of the composites. The addition of SiC significantly improved the bending strength and elastic modulus with values of 601 MPa and 474 GPa, respectively, but decreased the fracture toughness with a value of 4.8 MPa.m1/2. The addition of GNPs has a positive effect on fracture toughness and flexural strength but a negative one on the hardness. The increasing amount of both GNPs has a positive influence on wear characteristics of the composites thanks to the described wear mechanisms.

The development of effective synthetic routes is important to manifest proper nature of specific materials. In-situ electrochemical functionalization possesses great advantages over conventional routes, especially facile way and leading to reaching elaborate sites of functional group. Here, we demonstrate the preparation of functionalized carbons by in-situ electrochemical reduction in an argon atmosphere for application in low-cost, environmentally benign, and high-performance oxygen-electrodes for non-aqueous Li–O2 batteries. A Li–O2 battery with functionalized carbon shows a high discharge capacity (100 times that of pristine carbon), high power and cycling stability. The outstanding performance is attributed to the high O2 affinity of the functionalized carbon surface that facilitates the formation of soluble and diffusible superoxide intermediates by the reduction of the remaining O2 competing with surface growth for Li2O2 formation.

The Guizhou high-sulfur coal and its demineralized coal were rapidly pyrolyzed in a drop tube furnace under an argon atmosphere at the high temperatures ranging from 700°C to 1200°C. The effects of...

ZrB2-SiCw (w-whisker) composite powders were synthesized by a microwave-assisted carbo/borothermal reduction method under argon atmosphere using zircon, boric acid, and activated carbon as starting materials. The optimized ZrB2-SiCw composite powder was obtained by adjusting heating temperature and amounts of boric acid and activated carbon. Further, the effect of the optimized ZrB2-SiCw composite powder addition on corrosion resistance of the Al2O3–ZrO2–C slide plate material against O2 and Ca-treated steel was investigated. The results showed that the relative content of ZrB2-SiCw increased with increasing temperature. The excess of boric acid favored the formation of the ZrB2-SiCw, and the optimum amount of boric acid was overdosed to 30–45 wt%. The corrosion resistance and thermo-mechanical properties of Al2O3–ZrO2–C slide plate material could be improved effectively with 6 wt% ZrB2-SiCw composite powder addition, which was attributed to the excellent oxidation and corrosion resistance of ZrB2-SiCw composite powder. In addition, ZrB2-SiCw could confer excellent thermal shock resistance and reduce the generation of cracks, ultimately preventing corrosive media from infiltrating into slide plates, further increasing corrosion resistance of the plates.

Alumina ceramics with different sintering temperatures in argon atmosphere were obtained using stereolithography-based 3D printing. The effects of sintering temperature on microstructure and physical and mechanical properties were investigated. The results show that the average particle size, shrinkage, bulk density, crystallite size, flexural strength, Vickers hardness, and nanoindentation hardness increased with the increase in sintering temperature, whereas the open porosity decreased with increasing sintering temperature. No change was observed in phase composition, chemical bond, atomic ratio, and surface roughness. For the sintered samples, the shrinkage in Z direction is much greater than that in X or Y direction. The optimum sintering temperature in argon atmosphere is 1350 °C with a shrinkage of 3.0%, 3.2%, and 5.5% in X, Y, and Z directions, respectively, flexural strength of 26.7 MPa, Vickers hardness of 198.5 HV, nanoindentation hardness of 33.1 GPa, bulk density of 2.5 g/cm3, and open porosity of 33.8%. The optimum sintering temperature was 70 °C higher than that sintering in air atmosphere when achieved the similar properties.

The paper presents the results of experimental studies of the arc discharge between the graphite electrodes in an argon atmosphere at a pressure of 0.1–100 kPa. The discharge was ignited after the destruction of a graphite bar heated by a fixed electric current and maintained for ~103 s at a temperature of ~3 kK. Evidence of the formation of liquid phase on the surface of the graphite electrodes at a temperature of ~3.2 kK is presented. Data on the saturated carbon vapor pressure are discussed. The pressure in the carbon triple point does not exceed ~0.1 kPa.

The Na2UF8 complex is an important intermediate compound in the purification of UF6 by the adsorption–desorption process during fluoride volatility of the spent nuclear fuel, and its decomposition ...

The melting lines of graphite and liquid carbon have been studied for a long time. However, numerous controversies still remain in this field; for instance, different experiments give different melting temperatures. In this work, we explore the melting lines of graphite and graphene by means of classical and ab-initio molecular dynamics. We show that the empirical models developed on the basis of experimental data (AIREBO potential, Tersoff potential and some others) fail to reproduce the properties of liquid carbon properly. The models fitted to ab-initio data (LCBOPII and GAP) give much better results. However, both types of empirical models and ab-initio simulations evidence the presence of smooth structural crossover in liquid carbon. We also show that the “melting” of graphene discussed in previous works on computer simulation is indeed sublimation and propose a novel method to simulate the melting of graphene: simulation of graphene sheet in argon atmosphere. The melting temperature of graphene in argon atmosphere appears to be close to the melting temperature of graphite.

Violet phosphorene, a recently produced elemental 2D material, is a promising electronic and optoelectronic structure. The work function and band alignment of phosphorene nanoflakes are essential for their heterojunction structure design. The work function of violet phosphorene nanoflakes has been shown to decrease with the increase in layers from 5.16 eV to 4.79 eV and tends to be stable on a gold substrate, which has been confirmed via Kelvin probe force microscopy. The work functions measured on a silicon oxide substrate are much higher due to charge accumulation. The experimental work function of few-layer violet phosphorene is different from the intrinsic work function due to substrate doping, while that of thick violet phosphorene nanoflakes approaches the intrinsic work function value. Various functionals have been adopted for the work function calculation of few-layer violet phosphorene and the values obtained have been compared to the experimental results. The band alignments of different layered violet phosphorene materials calculated using the most accurate functional are demonstrated and compared to those of well-known materials to give a practical route for future applications. The work functions of the violet phosphorene nanoflakes have been shown to decrease due to oxidation, but they significantly improve after annealing in an argon atmosphere.

An investigation was conducted to evaluate the stress corrosion cracking resistance of copper based alloys. Cu, Ni, Sn of appropriate weight percentage were melted in a graphite crucible in an electric furnace under the argon atmosphere. The obtained specimens were solutionised and aged as per standards. The heat treated samples were subjected for microstructural evaluation and stress corrosion cracking test as per ASTM standard. In the microstructural analysis it was observed that the dendritic structure was completely vanished when the specimen was subjected to solutionising and aging. The stress corrosion cracking (SCC) was predominant in the regular bronze due to the formation of oxide layers according to the passive film rupture theory. But in the case of spinodal alloys only internal cracks were observed. These observed cracks were due to the pits and burrs present in the alloy

The Pidgeon process is the main extraction method of magnesium, but its continuous production cannot be achieved due to the switch between vacuum and atmospheric pressure. Therefore, it is vital to realize continuous extraction of magnesium under atmospheric pressure. In this paper, the process of extracting magnesium from prefabricated pellets in flowing argon was proposed. The isothermal kinetic analysis of the reduction process was carried out. The results showed that the reduction process was controlled by diffusion process in 1 h, and the apparent activation energy of extracting magnesium from prefabricated pellets in flowing argon was 218.75 kJ/mol. Then the influence of experimental factors on the reduction rate was explored, including briquetting pressure, carrier gas flow rate, ferrosilicon content, reaction temperature and time. Through analysis and calculation, it was concluded that the main control step of diffusion process was silicon diffusion.

As a star of the MXene materials, 2D titanium carbide (Ti3C2Tx) has attracted broad interest from worldwide researchers in view of its potential application in energy storage, chemical sensing, electromagnetic interference shielding and flexible electronics. In order to further improve performances and satisfy the needs of emerging flexible applications, there is an urgent need to increase the electronic conductivity, environmental stability and flexibility of Ti3C2Tx film. Herein, a two-stage thermal treatment process in an argon atmosphere at low temperature (300 °C) is proposed to address this challenge. The resulting Ti3C2Tx film shows a 16-fold increase in electronic conductivity, while its environmental stability and flexibility are also greatly enhanced. Furthermore, systematic investigation into the microstructure and variations of Ti3C2Tx films before and after thermal treatment shed light on the underlying mechanism, which contributes to a deeper understanding of MXene properties and offers general guidance for improving the performance of MXene films.

In this work, the Spark plasma sintering technique has been used to sinter ZrB2-B4C (20 wt%) composite at 2100 °C and 50 MPa uniaxial pressure for 15 min soaking in an argon atmosphere. XRD analysis has been carried out on the sintered sample to analyze the different phases present in the ZrB2-B4C composite. The Rietveld refinement technique has been used to analyze the crystal structure, the unit cell information such as space group, cell position, cell angles and atomic distances of the composite material using FULLPROF software.

Aluminum is the key ingredient in low-density steels. It leads to the formation of δ-ferrite in a large fraction. In order to study the influence, two different experimental approaches were devised. In a first of its kind, the sample was arc melted in an argon atmosphere. Later, the same alloy composition was ball milled and sintered at 1000 °C by avoiding liquid to δ-ferrite in the system. In the current study, the comparative analysis led by DICTRA simulation indicates that kappa (κ) carbide has difficulty forming in the present alloy system when δ-ferrite is already available, particularly during solidification casting.

A key challenge faced by the chemical industry is to develop some inexpensive and efficient catalysts with defined sites for selective hydrogenation. Herein, carbon-based materials with specific morphology (Bulks, Nanotubes and Nanosheets, respectively) confined Ni (0) and Ni-Nx active sites have been synthesized by using one Nickel-organic framework (Ni-MOF) as the precursor in high-temperature treatments under argon atmosphere (designated as Ni (0)/Ni-N-CBK, Ni (0)/Ni–N-CNT and Ni (0)/Ni–N–CNS, respectively). Interestingly, the key to obtaining a specific morphology of the carbon-based materials is altering the amount of additional nitrogen source (dicyandiamide, DCDA). The catalytic performance towards α, β-unsaturated aldehyde hydrogenolysis demonstrates that the Ni (0)/Ni–N-CNT and Ni (0)/Ni–N–CNS possess superior selective hydrogenation activity and stability, which could be put down to the synergy effect of Ni (0) and single atomic Ni-Nx species.

The effect of polysilazane on the densification and mechanical properties of SiC f /SiC composites was examined thoroughly. The polysilazane was infiltrated into the fiber area, followed by pyrolysis at 1450°C for 4 h in an argon atmosphere. Furthermore, the SiC fabrics contain the pyrolyzed polysilazane was infiltrated by β-SiC slurry and sintered at 1750°C for 2 h in an argon atmosphere. The density of SiC f /SiC composites with and without the addition of polysilazane was 2.65 and 3.05 g/cm 3 , respectively. The pores in the fiber area were observed for the SiC f /SiC composites with the addition of polysilazane. However, the fine-grained size in the matrix area was obtained by the addition of polysilazane. The average grain size of the SiC f /SiC composite with and without the addition of polysilazane was 253 and 740 nm, respectively. Indeed, the hardness of the matrix area for SiC f /SiC composites with the addition of polysilazane (31.6 ± 1.8 GPa) was higher compared to SiC f /SiC composites without polysilazane (27.4 ± 1.6 GPa).

In this paper, four Nb-xTi-16Si–3Cr–3Al-2Hf-yZr (x + y = 20) alloys prepared by arc-melting furnace with non-consumable tungsten electrode, which was heat-treated at 1400 °C/50 h in argon atmosphere. The microstructures of the as-cast alloys and the heat-treated alloys were observed, and the room temperature fracture toughness and the hardness were tested. The results indicated that with the increase of Zr content, γ-Nb5Si3 phase appeared in as-cast alloys with an increasing volume fraction. After heat treated, the microstructures of the alloys were finer, and the transformation from γ-Nb5Si3to α-Nb5Si3 occurred. In addition, the room temperature fracture toughness and hardness of the heat-treated alloys are higher than those of as-cast alloys. For heat-treated alloys, the room temperature fracture toughness presented a slight downtrend followed by an uptrend with increase proportion of Zr, however the hardness was being improved. By contrast, for as-cast alloys the toughness and the hardness decreased.

Lead-bismuth eutectic liquid metal (LBE) is the primary coolant for the advanced liquid-metal nuclear reactor, and clarification of its lubrication behavior and mechanism at elevated temperature is of importance. In this paper, a self-mated high-temperature steel sliding-pair and a pin-on-disc configuration are selected to evaluate the lubrication behaviors of LBE at 250 °C and 400 °C under argon atmosphere. It is found that LBE possesses an excellent lubricity proofed by the low friction coefficient of 0.1 and the wear rate of 10−6 mm3/Nm for the steel discs. Close inspection on the friction interfaces indicates that the worn surfaces of the steel discs are covered by a smooth tribo-film consisting of Bi, Pb7Bi3 and the related oxides.

The wetting of 12Cr18Ni10Ti and EK-173 reactor steels by an eutectic melt of PbBi with lithium under conditions of a vacuum and an argon atmosphere is studied in a wide range of temperatures. A tendency is observed toward the improved wetting of 12Cr18Ni10Ti steel with a higher lithium content in a eutectic melt of PbBi. It is found that an eutectic PbBi alloy with 20.86 at % of Li content tends to improve the wetting process under the conditions of a vacuum and an argon environment.

In this study, (Ni70Si30)100−x Fe x (x = 0, 5, 10) alloys were synthesized through the arc-melting technique under a vacuum/argon atmosphere. The microstructural properties and microhardness of the nickel (Ni)–silicon (Si)–iron (Fe) alloys were characterized. These alloys were investigated by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and Vickers microhardness measurement. The XRD results showed that all alloys have some intermetallic phases such as Ni2Si, Fe2Si, Ni74Si26 and Fe3Ni. These phases were confirmed by SEM-energy-dispersive X-ray spectroscopy analyses. From OM images, planar and dendritic growths were observed. The obtained phases affected positively the microstructures of the alloys. Thus, the microhardness values of the alloys improved and were determined to be in the range 866–1024 HV. Moreover, these microhardness values revealed that the iron content in the the nickel–silicon alloy system was a very significant factor to be determined increasing and decreasing of the the microhardness values the alloys.

In this study, hot corrosion behaviours of Haynes 282 (H282), Nimonic 90 (N90), and Haynes HR160 (HR160) in LiCl-Li2O molten salt were investigated at 650 °C under argon atmosphere. The corrosion rate was in the order of H282

We prepared a two-dimensional transition metal carbide Ti2CTx by treatment of Ti2AlC in molten fluoride salt. Two fluorinated salt systems were used to etch Al from Ti2AlC powder precursor under the argon atmosphere, and then the resulting MXene was delaminated with TBAOH to produce few-layered nanosheets of Ti2CTx. The reaction was undergone at different temperatures to study the effect of temperature. The results show that the optimal reaction temperature is 600 °C in LiF-NaF-KF system, and 850 °C in NaFKF system. The molten salt treated products are delaminated and quasi-2D MXene sheets can be obtained. The thickness of the MXene sheets prepared from the binary molten salt system is smaller than that of the ternary molten salt system.

A 304 stainless steel/medium carbon steel clad plate was fabricated by hot-rolling in an argon atmosphere. The interfacial microstructures of the clad plates were observed by SEM, and the carbide phases were identified by XRD and TEM. The effect of the rolling parameters on the shear strength and composition diffusion was analyzed. The results show that a sensitization region appears in the stainless steel side and a decarburization region is present in the carbon steel side. The sensitization region is composed of a dual structure, ditch and full-depletion of chromium zones. The precipitates in the stainless steel side are Chromium-rich M23C6 carbides.

In this paper, a type of macroporous carbon (MPC) material was produced using water-soluble sodium carbonate (Na2CO3) as the template and glucose as the carbon precursor. After annealing in an argon atmosphere (Ar) at 700 °C, the samples exhibited specific surface areas up to 600 m2 g−1 with different proportions of sodium carbonate and glucose. When the samples were employed as anode materials in lithium-ion batteries, the electrodes delivered a stable reversible capacity at 200 mA g−1 and favourable cycling stability at 500 mA g−1. Moreover, all MPC samples exhibited excellent rate performances at 5000 mA g−1.

The thermal decomposition of post-consumer samples of a carbonated water bottle made of poly(ethylene terephthalate), PC-PET, was examined by linear temperature programing under an argon atmosphere...

Graphene has attracted enormous attention due to its unique physical properties and attractive applications in many fields. However, it is an ongoing challenge to develop a facile and low-cost method for the large scale preparation of high-quality graphene (HQGr). In this work, we have developed an improved liquid-phase exfoliation method to mass produce HQGr. This method is quite simple but efficient by exfoliation of graphite in organic solvent with the co-assistance of sodium citrate and water. Remarkably, the concentration of as-exfoliated HQGr was as high as 0.71 mg/mL under optimal conditions, while the oxygen content in HQGr was only 2.39%. After annealing at 500 °C for 2 h in argon atmosphere, the mean conductivity of annealed HQGr was as high as 1.4 × 104 S m−1. Therefore, this facile method for liquid-phase exfoliation of graphite has excellent potential in the industrial-scale production of HQGr for numerous applications in energy storage, optical and electronic fields.

The effects of partial substitution of La by Ce and Ni by Al, Fe, or Co in LaNi5-based alloys on hydrogen storage performance were systematically studied. All samples were prepared using vacuum arc melting in an argon atmosphere. The results showed that for La-Ni5−xMx (M = Al, Fe, or Co) alloys, the lattice constants and unit cell volumes increased with an increasing amount of Al and Fe. On the other hand, these parameters decreased upon partial substitution of La by Ce. In addition, the lattice constant remained almost constant in the La0.6Ce0.4Ni5–xCox alloys regardless of the value of x (x = 0.3, 0.6, or 0.9), as Ce might enhance the homogeneity of the CaCu5-type phase in Co-containing alloys. The hydrogen storage properties of the alloys were investigated using pressure, composition, and temperature isotherms. The experimental results showed that the plateau pressure decreased with an increasing content of Al, Fe, or Co, but it increased with Ce addition. Furthermore, the plateau pressures of all Co-containing alloys were almost identical upon substitution with Ce. Finally, the enthalpy (ΔH) and entropy (ΔS) values for all alloys were calculated using van’t Hoff plots. The relationship between the lattice parameters and enthalpy changes for hydrogenation will be discussed.

Effect of CaO addition on phase formation in the Fe-Fe2O3-V2O3 system under argon atmosphere was investigated by x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and differential scanning calorimetry. The results showed that the major phases were Fe2VO4, Fe3O4, and FexO4 (2.8

Using the wide-angle and small-angle X-ray diffraction techniques, the Mo density is obtained as a function of the layer thickness in periodic X-ray Mo/Si mirrors synthesized by magnetron sputtering in an argon atmosphere. By the example of a simulated aperiodic multilayer Mo/Si mirror, the necessity to take into account the real density of Mo and the incorrect use of its tabulated densities is demonstrated.

Nano-aluminum particles are fabricated by the electrical explosion of wires (EEW) in argon atmosphere. The characteristics of the current, voltage, and the deposited energy of exploding Al wire with and without the shunting gap are studied. In order to understand the influence of the partial reheating process on the production of nanoparticles, the shadowgraphs are used to study the expansion process of the exploding Al with and without the shunting gap, it is observed that the expansion rates of exploding Al without the shunting gap have two peaks, while the expansion rates of exploding Al with the shunting gap have only one peak. The size and shape of the nanoparticles are analyzed using scanning electron microscopy (SEM) analysis. It is found that almost all the nanoparticles are basically spherical in shape, and the average particle size under different experimental conditions are obtained using SEM. The study of the partial reheating process suggests that the partial reheating process can reduce the average size of the nanoparticles.

The nanoscaled (up to 30 nm) TiC, ZrC, HfC, VC, NbC and TaC monocarbides with NaCl-type structure have been synthesized from the elemental metals and the carbon nanotubes (CNTs) by mechanical alloying in a high energy planetary ball mill in an argon atmosphere. The powders obtained were examined by X-ray diffraction method. It is shown that mechanical alloying is accompanied by a decrease in the lattice parameters of MeC carbides formed and by a decrease of the total number of atoms in their crystal structure, i.e. by an increase of structural vacancies in the materials obtained. On the whole, monocarbides obtained can be arranged by the simplicity of their formation in a ball mill as: HfC -> ZrC -> TiC -> TaC -> NbC -> VC.

Present study investigates microstructural stability and mechanical properties of spark plasma sintered Fe-Cr-Nb alloys for its nuclear first wall reactor application. The nanostructured alloys were prepared by mechanical alloying (MA) for 25 h in argon atmosphere (purity