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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.

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.

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.

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).

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.

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.

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.

SUMMARY Environmental magnetism has become more and more popular because it is inexpensive, rapid and non-destructive. However, the environmental implication of traditional magnetic parameters is changed as the weathering intensity is contrasting. For example, magnetic susceptibility cannot be used as pedogenic index for strongly weathered red soils. Thermal magnetic measurement is a common way to identify magnetic minerals in rocks and sediments. Susceptibility enhancement after a 700 °C heating cycle in an argon atmosphere usually happened for various rocks and sediments. The increase is caused by formation of new magnetite from iron derived from paramagnetic iron-containing minerals. This is similar to pedogenesis or weathering process. The heating process in lab released the residual iron in weatherable iron-containing silicates which has not yet been depleted by contemporary pedogenesis or weathering. This residual iron can be quantified by the amount of susceptibility increase after a heating cycle. A negative correlation between the susceptibility increase after heating and the weathering intensity has been found in high-temperature magnetic susceptibility measurements of several sequences located in different climate zones. Results suggest that the degree of weathering can be estimated for intensely weathered red soils as well as for scarcely weathered loess using the amount of susceptibility change after a 700 °C heating cycle. This study provides new perspectives for developing new weathering and pedoclimate proxies using environmental magnetism.

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 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 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.

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 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 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.

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.

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

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.

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.

Four metallurgical cokes were heat treated at 1250 °C to 1550 °C in argon atmosphere. The influence of heat treatment on the microstructure of metallurgical cokes was characterized using X-ray diffraction and Raman spectroscopy. Wettability experiments were carried out using the sessile drop technique. The wettability of cokes with liquid Fe-85wt%Mn at 1550 °C was measured as a function of time. The effect of coke ash content, microstructure, porosity and roughness on the wettability was investigated. In the process of heat treatment, the microstructure of the metallurgical cokes transformed toward the graphitic structure. The Raman spectra showed variations reflecting their temperature histories. Area fraction of G peak increased as the annealing temperature increased and intensity ratios of D to G band decreased with temperature. All the four coke samples showed non-wetting behavior with Fe-85wt%Mn while graphite showed wetting behavior. Coke E with the highest roughness and porosity showed the lowest wettability compared to other cokes. Crystallite size of the coke samples did not seem to have any significant effect on the wettability. © 2020 The Author(s). Published with license by Taylor and Francis Group, LLC This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4. 0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.

In this study, Al matrix composites consisting of different amounts of Zn, Cu, and Mg were produced using the powder metallurgy technique. In the alloying, powders were ball milled for 120 min via mechanical alloying. After alloying process, the powders were pressed at 800 MPa at room temperature. Sintering (2 h at 600 °C in argon atmosphere), solution treatment (2 h at 480 °C), and aging processes (3, 6, 9, and 12 h, respectively, at 120 °C) were applied to the samples. The hardness and tribo-metallurgy properties of the products were investigated. After sintering, the hardness values of the three alloys were close to each other; however, the solution treatment after sintering caused the hardness values to increase significantly. It was determined that the Al-2Zn-5Cu-4Mg alloy had the highest hardness increase with the 6-h aging heat treatment. The wear resistance of the materials in all the compositions had increased. The highest wear resistance and lowest friction coefficient were obtained for the Al-2Zn-5Cu-4Mg alloy with the 6-h aging heat treatment. © 2020 Authors. Published by association for ETRAN Society.

The article considers thermal characteristics of the radioactive graphite–CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere. Thermodynamic calculations were carried out in the Terra program. Four temperature ranges with changes of thermal characteristics of the radioactive graphite–CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere have been determined.

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.

Phase equilibria of the CaO-Gd2O3-SiO2 slag system at 1773 K and 1873 K were investigated by characterizing equilibrated samples with electron probe microanalysis (EPMA). Four three-phase equilibria and five two-phase equilibria are formed in the CaO-Gd2O3-SiO2 ternary system at 1773 K in argon atmosphere. While three three-phase equilibria, six two-phase equilibria and one liquid phase are presented in the system at 1873 K. The isothermal section of the phase diagram is thereafter constructed based on the experimental results. The feasibility of the rare earth recovery is also discussed based on the phase relations.

We propose a method to identify calcium aluminate inclusions in calcium-treated aluminum-killed steels (Ca12Al14O33, CaAl4O7, CaAl12O19, and Al2O3) using cathodoluminescence (CL) analysis. Such inclusions result in nozzle clogging and melting of the stopper rod during continuous casting. We obtain CL images and CL spectra of calcium aluminate inclusions in model samples of calcium-treated aluminum-killed steel. The model samples are prepared by heating mixtures of Fe powder, Al powder, and Ca shot at 1550 °C in an argon atmosphere. On the basis of the CL colors and CL spectra of the calcium aluminate inclusions, we demonstrate that it is possible to distinguish Ca12Al14O33, CaAl4O7, CaAl12O19, and Al2O3 inclusions from CaAl2O4 and Ca3Al10O18 inclusions, which do not cause nozzle clogging and melting of the stopper rod, by comparing CL images obtained using digital cameras with and without a built-in filter. The acquisition times for the CL images are less than 10 seconds. Thus, the method we present here can be applied for the rapid detection of harmful calcium aluminate inclusions during continuous casting. The CL spectra also provide basic information to specify compositions in agglomerated calcium aluminate inclusions.

A Mo-Si-B coating was prepared on an Nb-Si based alloy by detonation-gun spraying of Mo followed by co-deposition of Si and B via pack cementation. The microstructural evolution and interdiffusion behavior of the coating/substrate system were investigated by annealing for different times at 1250 °C in argon atmosphere. The results show that the interdiffusion zone has a two-layer structure consisting of (Mo, X′)5Si3 (X’ = Nb, Ti, Cr, Hf) and (Nb, X)5Si3 (X = Ti, Cr, Hf), respectively. The growth of the transitional layer, which obeys a parabolic rate law, is dominated by the inward diffusion of Si from the outer layer to the substrate. The interdiffusion coefficients of Si in the transitional layers are calculated using a modified method based on the Boltzmann-Matano analysis.

MgB2 wires with iridium doping were manufactured using the in-situ technique in a composite Cu-Nb sheath. Reaction was performed at 700°C, 800°C or 900°C for 1h in argon atmosphere. A maximum of about 1.5 at.% Ir replaces Mg in MgB2. The superconducting transition temperature is slightly lowered by Ir doping. The formation of IrMg3 and IrMg4 secondary phase particles is evidenced, especially for a nominal stoichiometry with 2.0 at.% Ir doping. The critical current density and accommodation field of the wires are strongly dependent on the Ir content and are generally weakened in the presence of Ir, although the effect is less pronounced at lower temperatures.

Kaolins are used in a multiplicity of industries because of unique physical and chemical properties. Relationships between thermal and radioactivity properties are discussed in its application as a building material. Super-fine kaolin powder with particle sizes about 30 mu m was analyzed. Simultaneous TGA/DTA analysis was performed on powder samples at various heating rates in an argon atmosphere. Based on investigated thermal properties, it was concluded that dehydroxylation process can vary depending on the characteristics of starting material. The maximum degree of the dehydroxylation (D (T)) was obtained at the lowest rate of heating (D (T) = 60.79% for 10 A degrees C min(-1)). With an increase in the heating rate, decline in D (T) value was observed. Based on comprehensive testing, it was identified that the degree of dehydroxylation does not drop below 50%. It was concluded that appointed experimental conditions seem sufficient admissible for obtaining degree of dehydroxylation (D (T)) higher than 50%. In order to safe use of kaolin as a building material from the standpoint of radiological safety, content of natural radionuclides was determined by gamma spectrometry.

The effect of thermomechanical treatment on mechanical and electrical properties of the Cu-Cr-Zr alloy was experimentally investigated through the Vickers micro-hardness, tension tests, and four-point probe method at room temperature. Three sets of experiments were carried out employing a commercially available alloy that was solution treated at 980 ˚C for 1 h in an argon atmosphere and water quenched. The order of the wire drawing or continuous hybrid processing and aging was varied to determine the effect of the thermomechanical treatment condition on material properties. The three-pass wire drawing and two-pass continuous hybrid processes after aging at 450 ˚C produced 508.8 MPa with 80.1% IACS and 529.4 MPa with 78.6% IACS, respectively. In conclusion, the continuous hybrid process might be an alternative to achieve the economical manufacturing in meeting the requirements for better strength and comparable electrical conductivity of the existing material compared to the conventional wire drawing.

ODS ferritic steels were produced by mechanical alloying (MA) in either attritor or planetary ball mills under argon atmosphere and hot extrusion. Milling in argon with controlling excess oxygen (Ex.O) and nitrogen was effective to reduce the particle size of MA powders. Coarse Al2O3 particles and fine AlN precipitates were found to be formed in an Al added steel when the Ex.O and nitrogen concentrations are increased. Lowering the Ex.O and nitrogen concentrations in ODS ferritic steels acted as a key parameter for enhancing their impact properties.

Studying of field electron emission properties of carbon cathodes operating under technical vacuum conditions is a promising scientific field. Massive cathode made of commercial fine-grained graphite of MG (Russian abbreviation) grade is being investigated. Experiments on obtaining current-voltage characteristics and long-term testing are being carried out. The emitter made of fine-grained graphite demonstrates good emission properties under technical vacuum conditions. Carbon cathode is capable of operating at pressures up to 2×10–2 Pa. Increased pressure in the vacuum chamber leads to deterioration of cathode emission properties. Electric field enhancement factors were calculated for all stages of studies. Analysis of experimental data demonstrates decrease in enhancement factor due to ion bombardment of cathode surface during exploitation. This results in higher electric field for operation of investigated graphite cold cathodes.

In this study, a cylinder of fine-grained carbon-bonded alumina was pressed uniaxially at high temperatures in an argon atmosphere. The resulting changes in mechanical properties, physical properties and microstructure were described with various techniques. The porosity of the material was found to have decreased significantly, leading to higher density, higher dynamic Young's modulus, higher strength and increased hardness. Additionally, gradients in porosity and hardness were observed that resulted from inhomogeneous temperature distribution during compression. Possibilities and conditions for the production of graded refractory materials can be deduced from the results.

The effect of two different annealing processes on the microstructure and barrier-forming ability of Cu-Zr alloy films has been investigated. Cu-Zr alloy films were deposited directly onto SiO2/Si substrates via direct current magnetron sputtering and subsequently annealed by the vacuum annealing process (VAP) or rapid annealing process under argon atmosphere at temperatures 350°C, 450°C, and 550°C. Then, the microstructure, interface characteristics, and electrical properties of the samples were measured. After annealing, the samples showed a preferential (111) crystal orientation, independent of the annealing process. After two annealing methods, Zr aggregated at the Cu-Zr/SiO2 interface and no serious interdiffusion occurred between Cu and Si. The leakage current measurements revealed that the samples annealed by VAP show a higher reliability. According to the results, the vacuum annealing has better barrier performance than the rapid annealing when used for the fabrication of Cu-based interconnects.