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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.

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.

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.

Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was examined by XRD, DSC−TG, and chemical analysis technologies. In the absence of ferric oxide, sodium cyanide decomposes at 587.4 °C in air and 879.2 °C in argon atmosphere. In the presence of ferric oxide, about 60% of sodium cyanide decomposes at 350 °C for 30 min in argon, while almost all sodium cyanide decomposes within 30 min in air or O2 with mass ratio of ferric oxide to sodium cyanide of 1:1. The increase of ferric oxide addition, temperature, and heating time facilitates the destruction of sodium cyanide. It is believed that with ferric oxide addition, NaCN reacts with Fe2O3 to form Na4Fe(CN)6, Na2CO3, NaNO2 and Fe3O4 in argon. NaCN decomposes into NaCNO, Na4Fe(CN)6, minor NaNO2, and the formed NaCNO and Na4Fe(CN)6 further decompose into Na2CO3, CO2, N2, FeOx, and minor NOx in air or O2.

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.

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.

The paper presents the results of studies of catalytic properties of cesium salts of heteropoly acids Cs4–хHхSiW12O40 (x = 3 and 3.5), Cs3–хHхPMo12O40 and Cs3–хHхPW12O40 (x = 2 and 2.5) for hydrolysis of cellulose to glucose at 180°C under argon atmosphere. Glucose is shown to be the main reaction product. The maximum hourly yield equal to 23% is observed in the presence of Cs3HSiW12O40. It is assumed that the catalyst efficiency is affected by the specific surface area. It is established that both heterogeneous and homogeneous processes occur in the presence of the salts due to leaching of the active component to the solution. The prepared salts are demonstrated to be more efficient than systems reported previously in literature.

A concise and environmentally friendly protocol has been developed for the synthesis of cis-dihydrochromenones and trans-dihydrochromenones in EtOH at room temperature. Irradiation of 4-phenyl-3-arylcoumarins in EtOH with 313 nm UV light under an argon atmosphere at room temperature gave cis-4b,15c-dihydro-16H-benzofuro[3',2':7,8]phenanthro[9,10-c]chromen-16-ones and cis-8c,14b-dihydro-9H-benzo[11,12]chryseno[5,6-c]chromen-9-ones in good yields. And an analogous treatment of 4-phenyl-3-alkenylcoumarins as 4-phenyl-3-arylcoumarins provided trans-1,2,3,4,4a,14b-hexahydro-5H-phenanthro[9,10-c]chromen-5-ones. The described photorearrangement proceeded smoothly without the addition of any transition metals and additives. The photorearrangement of 4-phenyl-3-arylcoumarins is believed to proceed via 6π-electrocyclization, a [1,3]-hydrogen shift and keto-enol isomerization.

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.

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 ...

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.

Close to spherical nanosized niobium diboride particles with an average diameter of 65 nm were synthesized by the reaction of amorphous boron with niobium powder at 1073 K in an argon atmosphere in KCl and Na2B4O7 ionic melts (autoclave, argon pressure of 4 MPa, 32 h).

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).

A strategy for the syntheses of benzofuranoquinolines and its analogues via the irradiation of o-phenylfuranyl/thienylpyridines/pyrimidines in DCM with UV light at rt under an argon atmosphere is described. The mechanism of this reaction through the process of 6π-electrocyclization, [1,5]-hydrogen shift, and 1,3-eneamine tautomerism leading to H2 evolution was elucidated. Notably, the syntheses of cis-8b-methyl-8b,13a-dihydrobenzo[f]benzofuro[3,2-h]quinolone via the photoinduced rearrangement of 2-(3-methylbenzofuran-2-yl)-3-phenylpyridine relevant to the mechanism of this reaction highlights the importance of the developed methodology.

The complexes of Zn(II)porphyrin with phenols (X) and pyridines (X') as the axial ligands in 1 : 1 molar ratio have been synthesized and characterized by elemental analysis and IR, UV-Vis, and 1H NMR spectroscopies. The fluorescence spectra show broadening and red/blue shifts of B and Q bands in axially ligated derivatives of [X/X'-Zn-t(p-OCH3)PP]. Thermal analysis for Zn(II)porphyrins have been carried out in an argon atmosphere from room temperature to 700°C using thermal analyzer. First-principle based theoretical calculations have been performed for axially ligated Zn(II)porphyrin complexes and the optimized geometrical parameters have been assessed. Zn(II)porphyrin complexes have been also screened for antibacterial activity against B.klebsiella, P. cereus, B. subtilis, A. denitrificans, S. aureus, K. pneumoniae by agar well diffusion methods with IZD range between 8 mm and 16 mm depending on the nature of the axial ligands that affect the IZD of the respective bacterial stain. The in vitro antifungal activity against the pathogen Fusarium sps. has been carried out by DDM.

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, 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

A convenient and efficient metal free, atom economical flexible synthesis of β-carbolines involving a domino Pictet-Spengler reaction and aromatization in oxygen atmosphere in N-methyl-2-pyrollidone (NMP) is described. Variety of aryl, heteroaryl and aliphatic aldehydes were found to be good substrates for this methodology. Several β-carbolines (6a-6t) and β-carboline methyl esters (7a-7e) were synthesized using this methodology.The same reaction carried out in argon atmosphere in the presence of catalytic amount of acid in NMP furnished, tetrahydro-β-carbolines (4a-4g).

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.

Co2TiO4 spinel (Co2TiO4-Sp) was synthesized at 1573 K and room P by heating in an argon atmosphere for 72 h, and quasi-hydrostatically compressed to ~ 24 GPa using a diamond-anvil cell in conjunction with a synchrotron X-ray radiation (ambient T). We found that the Co2TiO4-Sp was stable up to ~ 21 GPa and transformed to a new phase at higher P. With some theoretical simulations, we revealed that this new phase adopted the CaMn2O4-type structure (Co2TiO4-CM), which might further transform to the CaTi2O4-type structure (Co2TiO4-CT) at ~ 35 GPa. The isothermal bulk modulus (KT) was experimentally obtained as 175.5(36) GPa for the Co2TiO4-Sp and 161(7) GPa for the Co2TiO4-CM, with its first pressure derivative $$K_{{\text{T}}}^{'}$$ as 2.8(5) and 7.3(8), respectively. Furthermore, the KT was theoretically constrained (the GGA method) as 138(3) GPa for the Co2TiO4-CM and 196.8(14) GPa for the Co2TiO4-CT, with the $$K_{{\text{T}}}^{'}$$ as 7.6(3) and 5.0(1), respectively. Consequently, the Co2TiO4-CM is ~ 12.3% denser than the Co2TiO4-Sp at ~ 21 GPa, whereas the Co2TiO4-CT is just ~ 0.8% denser than the Co2TiO4-CM at ~ 35 GPa. The spinel and post-spinel phase assemblages for the Co2TiO4 composition at some high T have been tentatively deduced as Co2TiO4-Sp, CoO-B1 (NaCl-type structure) + CoTiO3-Ilm (ilmenite-type structure), 2CoO-B1 + TiO2-α-PbO2 (α-PbO2-type structure), Co2TiO4-CM and Co2TiO4-CT, as P increases.

The influence of mesoporous silica matrix on the thermolysis of ferric oxalate loaded into its pores was studied. A significant decrease in the onset of the thermal decomposition temperature of ferric oxalate was observed. The maximum of the second decomposition stage of ferric oxalate in argon atmosphere was also appeared to be shifted by 30-40°C when thermolysis occurred in pores. These effects were accounted for the amorphous state of ferric oxalate and enhanced reactivity of highly dispersed particles

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.

Temperature dependence of graphene oxide resistance during continuous heating and cooling under argon atmosphere at 300–550 K and Raman spectra were studied. Resistance is constant within 300–370 K during cooling. It is thermostable under further heating. Temperature dependence of resistance changes according to activation law within 370–550 K. The decrease of resistance at the increase is related to the removal of functional oxygen-containing groups, which is proved by the results of Raman spectra.

Presently, the majority of titanium powder metallurgy components produced are sintered under high vacuum due to the associated benefits of the vacuum atmosphere. However, high-vacuum sintering is a batch process, which limits daily production. A higher daily part production is achievable via a continuous sintering process, which uses argon gas to shield the part from air contamination. To date, there has been limited work published on argon gas sintering of titanium in short durations. This study investigated the properties of thin high green density titanium strips, which were sintered at the temperatures of 1100 °C, 1200 °C and 1300 °C for a duration of 30 min, 60 min and 90 min in argon. The strips were produced by rolling of −45 µm near ASTM (American Society for Testing and Materials) grade 3 hydride–dehydride commercially pure titanium powder. The density, hardness, tensile properties and microstructure of the sintered strips were assessed. It was found that near-full densities, between 96 and 99%, are attainable after 30–90 min of sintering. The optimum sintering temperature range was found to be 1100–1200 °C, as this produced the highest elongation of 4–5.5%. Sintering at 1300 °C resulted in lower elongation due to higher contaminant pick-up.

Mo-48.2% Ag films were fabricated by direct current (DC) magnetron sputtering and annealed in an argon atmosphere. The effects of annealing on the surface morphology, resistivity and surface-enhanced Raman scattering (SERS) performance of Mo-48.2% Ag films were investigated. Results show a mass of polyhedral Ag particles grown on the annealed Mo-48.2% Ag films&rsquo, surface, which are different from that of as-deposited Mo-Ag film. Moreover, the thickness and the resistivity of Mo-48.2% Ag films gradually decrease as the annealing temperature increases. Furthermore, finite-difference time-domain (FDTD) simulations proved that the re-deposition Ag layer increases the &ldquo, hot spots&rdquo, between adjacent Ag nanoparticles, thereby greatly enhancing the local electromagnetic (EM) field. The Ag layer/annealed Mo-48.2% Ag films can identify crystal violet (CV) with concentration lower than 5 &times, 10&minus, 10 M (1 mol/L = 1 M), which indicated that this novel type of particles/films can be applied as ultrasensitive SERS substrates.

A series of experiments were performed using a 500 W continuous wave fibre laser on a single powder bed layer using different processing variables. The aim was to investigate the effect of different shielding conditions on melting behaviour and bead profile in laser powder bed fusion (PBF). Through high-speed imaging, it was found that under an argon atmosphere a strong plasma plume is generated from the meltpool. Laser beam-plasma plume interactions caused strong instabilities during melting, including laser wandering, track instability and continuous fluctuations between melting regimes (conduction and keyhole). Hence, it was not possible to control the profile of the melted tracks under this condition. By using a helium atmosphere, a smaller plasma was obtained, reducing the disruptions caused by laser-plasma interactions. This led to a stable melting regime that allowed control of the melt bead profile. This condition was used to study the effect of laser-material fundamental interaction parameters on the bead geometry in powder bed melting. It was found that during melting of single tracks, the dominant regime of melting is conduction for the range of parameters tested. Penetration and melt width were found to increase with increasing energy density. For longer interaction times, melt widths were found to be up to ten times the size of the beam diameter used. Fluid flow modelling showed that this is due to strong melt flow as consequence of surface tension gradients generated by very high temperature gradients.

The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800 &deg, C. Above 600 &deg, C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500 &deg, C and is completely oxidized above 700 &deg, C.

The treatise studies the influence of CuxMoySz−based coating magnetron-sputtered on the working surface of copper specimens working in a friction pair with a copper counterbody on the wear kinetics in vacuum as compared to the wear in argon atmosphere. The tribological tests were performed using the “rotating disk–coated pad” scheme. The work establishes 1.8 times decreased wear rate of the friction pair working in vacuum. It is shown that the life of CuxMoySz coatings linearly raises with their thickness growing up to 60 µm.

N-heterocyclic carbene (compound b) was synthesized from reaction of 1-(3-phenylpropyl)-3-methylbenzimidazolium iodide (a) and a strong base in an argon atmosphere. Then, 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate (c) was prepared with carbene and CS2. Finally, a group of alkyl 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate halides was synthesized with alkyl halides and compound c, occurring products 1-6. Structural characterization of compounds was performed 1H, and 13C NMR, IR, and MS spectroscopy and elemental analysis.

Titanium carbide (TiC) nanowires are synthesized by carbothermal reduction reaction at 1473–1673 K in argon atmosphere. The structure and morphology of TiC nanowires are characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The chemical reaction thermodynamics and the growth mechanism of TiC nanowires are investigated based on the Ti-C-O-Cl system. It involves the formation of gaseous TiClx and CO crucial intermediates, and the further carbon reduction of TiClx to TiC. Based on the thermodynamic analysis, the two-stage growth mechanism of TiC nanowires is discussed. The work could help to analyze the thermochemistry of the carbothermal reduction reaction in the Ti-C-O-Cl system, which is beneficial to optimize the temperature and the input precursors for controlling TiC nanowires growth.

Waste walnut shell was selected and carbonized in different atmospheres to prepare excellent light-to-heat conversion materials for efficient solar-driven water evaporation. Carbonized walnut shell has a unique concave structure and rough surface, and its light absorption rate is higher than 88% in the full-spectrum range of 200–2500 nm. Moreover, under one-sun irradiation, carbonized walnut shell in a hydrogen/argon atmosphere mixture has better water evaporation performance (1.22 kg m-1h−1) and a higher η value (81.4%) than the carbonized walnut shell in an argon atmosphere. The main reason was due to its higher degree of graphitization and smaller surface pores, which are beneficial to light-to-heat conversion. Our work highlights the great potential of the waste biomass material (walnut shell) for realizing a highly effective solar energy-driven water evaporation.

The FeCo@SiO2/holey reduced graphene oxide composite was successfully prepared by combining liquid-phase reduction reaction in argon atmosphere with high-temperature calcination. The FeCo@SiO2/holey reduced graphene oxide composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy analysis and exhibit excellent electromagnetic wave absorption properties. The maximum reflection loss of FeCo@SiO2/holey reduced graphene oxide composite reaches –46.28 dB at 16.16 GHz with the thickness of 1.5 mm and the absorption bandwidth with the reflection loss below –10 dB was up to 3.92 GHz (from 14.08 GHz to 18 GHz) with the thickness of 1.5 mm. The absorption bandwidth with RL below –10 dB is up to 12.64 GHz. It is believed that the FeCo@SiO2/holey reduced graphene oxide composite can serve as an excellent microwave absorber.

The temperature distribution over the melt surface in an anode spot is measured during plasma arc heating of a metal at a pressure of 10 and 0.1 MPa in an argon atmosphere by a spectral method. The measurements are performed in the wavelength range where the discharge continuum intensity is minimal (240–450 nm). The spectral regions that are free of lines (340, 440 nm) are chosen to determine the anode (melt) and cathode (tungsten) temperatures. The tungsten cathode temperatures are 3160 and 3317 K at a discharge current of 150 and 220 A, respectively, and a pressure of 10 Pa. At a discharge current of 150 A, the maximum iron melt surface temperature in an anode spot is 3031 K. At a pressure of 0.1 MPa and 225 A, the maximum temperatures at the iron, tungsten, zirconium, and nickel melt surfaces are 2960, 4120, 4040, and 3590 K, respectively.

We present critical temperature measurements of titanium thin films annealed in an argon atmosphere at various temperatures. We are able to depress the $${T}_{\text {C}}$$ by up to 200 mK from an initial $${T}_{\text {C}}$$ of 540 mK by increasing the temperature at which the films are post-annealed from 80 to 275 $$^{\circ }$$ C. We find an anti-correlation trend between the annealing temperature and the measured $${T}_{\text {C}}$$ . We also briefly discuss how we plan to use these films to produce TES detectors to be used in the LSPE/SWIPE balloon-borne cosmic microwave background polarimeter, which is slated to launch in December 2019.