X-ray Phase Research Articles

Research of physical-mechanical and physical-chemical properties of foam concrete with complex polymer - mineral additive of a new generation based on local raw materials

The results of physical-mechanical and physical-chemical analysis using X-ray phase analysis of foam concrete and the processes of change in hydration, crystallization in cement systems, with the addition of complex chemical additives of the new generation of the Relaxol KDJ-3 series are presented. It has been established that in cement systems these additives help create new formations that crystallize in a finely dispersed form, clog the pores and capillaries of Portland cement stone, compacting and strengthening its structure.

ИССЛЕДОВАНИЕ ФАЗОВОГО СОСТАВА КОМПОЗИЦИОННЫХ ВЯЖУЩИХ ДЛЯ ГИДРОТЕХНИЧЕСКОГО БЕТОНА

The article studies production of composite binders for hydraulic concrete. Vitreous perlite from the Mukhor-Tala deposit of the Republic of Buryatia was used as an active mineral additive for the composite cement binder. Pozzolanic activity of vitreous and crystallized perlites was determined. Assessment of physical and mechanical properties and phase composition of autoclave-cured lime-perlite binders were carried out for subsequent assessment and identification of the hydrate phases of the composite cement binder. An X-ray phase analysis of Portland cement and a composite binder with vitreous perlite with a specific surface area of 600 m2/kg was carried out. The study established that use of active mineral additive based on glassy perlite leads to increase in amount of low-basic calcium hydrosilicates in cement stone. Electron microscopic analysis of composite binders for concrete hydraulic structures was carried out.

Влияние механической обработки исходных реагентов на структурные и электрические свойства LiFeO2 керамики

This work investigates the effect of mechanical treatment of initial Fe2O3 and Li2CO3 powders on the structure and electrical properties of lithium ferrite ceramics of the chemical composition LiFeO2. Mechanical treatment was carried out in an AGO-2S ball mill for 60 minutes at a bowl rotation speed of 2220 rpm. Sintering of ceramic samples was carried out in a laboratory furnace at 1050 °C for 1 hour. Using X-ray phase analysis data, it was shown that the introduction of the mechanical treatment of powders leads to a decrease in the concentration of the α-LiFeO2 phase in ferrite ceramics from 97,9 to 93,9 wt.%, as well as an increase in the secondary LiFe5O8 phase from 2,1 to 6,1 wt.%. In this case, during sintering, a more homogeneous and finely porous structure of the samples was formed. Based on the temperature dependences of the electrical conductivity of the samples, it was established that changes in electrical resistance are associated both with the microstructure and with the processes of adsorption-desorption (depending on temperature) of gas from the surrounding atmosphere into ferrite ceramics. The ferrite ceramics obtained by mechanical treatment is of interest for its further use as an adsorption material for carbon oxides.

Modeling of X-Ray Phase Contrast Imaging of Optically Heterogeneous Objects

Modeling of X-Ray Phase Contrast Imaging of Optically Heterogeneous Objects

Mechanical Activation as a Stage of Coal Sample Preparation in the Analysis of Rare Earth Elements Content by Inductively Coupled Plasma Mass Spectrometry

Background: Brown coals are recognized as promising sources of rare earth elements (REEs). Rare earths are present in both the mineral and organic parts of brown coal. Objectives: This study was conducted to investigate the influence of preliminary mechanical activation in the process of sample preparation prior to analyzing the concentrations of rare earth elements in brown coal samples of various origins and compositions Methods: Four coal samples from different deposits in Russia were selected for the study. Samples were treated with mechanical activation, without reagents, or mechanochemical activation, with humic acids added externally as reagents. X-ray phase analysis was carried out with the selected samples. The quantities of rare-earth elements present in the samples were studied by the method of high-sensitivity inductively coupled plasma mass spectrometry (ICP-MS). Results: It was found that the mechanical activation of coal before dissolution in a mixture of nitric and hydrofluoric acids leads to an increase in the determined concentration of rare earth elements. For this study, the expediency of using only nitric acid as an optimal solvent for the elemental analysis of coal samples was shown. The total concentration of all REE after dissolution of nitric acid and mechanochemical activation with humic acid reached 2456 g/t in Vanchin coal, 968 g/t in Azeysky coal, and 24 g/t and 150 g/t in Itatsky and Spetsugli coals, respectively. Conclusion: Mechanical activation and mechanochemical treatment can greatly help to facilitate sample preparation of natural objects, such as coals for elemental analysis, but in some cases, only a change of solvent is sufficient. When developing technology for concentrating rare earth elements from coal involving grinding, it is necessary to take into account the fact that mechanical activation of coal changes its tendency to dissolve, which may affect the results of the analysis and should be taken into account during experiments.

Synthesis, thermal stability and catalytic activity of Ce0.72Zr0.18Pr0.1O2-δ nanodispersed solid solution in CO oxidation reaction

A nanodispersed solid solution based on the Ce0,72Zr0,18Pr0,1O2-δ crystal lattice was synthesized by co-precipitation followed by heat treatment. The identification of the material was carried out by X-ray phase analysis, energy dispersive analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, low-temperature nitrogen adsorption, and gas chromatography. It has been established that the synthesized Ce0,72Zr0,18Pr0,1O2-δ solid solution is superior in catalytic activity and thermal stability to CeO2 and Ce0,8Zr0,2O2 due to doping with Pr+3 ions.

Термическое разложение бензоатов и аминобензоатов Mn (II), Co (II), Ni (II), Cu (II)

The article discusses the main methods for obtaining carbon composite nanomaterials and highlights the thermolysis method as one of them. To understand the essence of thermal decomposition processes as a synthesis method for carbon nanomaterials, thermolysis of aromatic carboxylates of such elements as manganese(II), cobalt(II), nickel(II), and copper(II) was considered. The article thoroughly discusses the synthesis procedure for these metal carboxylates under simple conditions. The thermal decomposition process was carried out in two environments (air as oxidizing one and argon as neutral one) to compare the products obtained. For a detailed study of the decomposition processes of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates, thermal analysis methods (TG and DSC) were used on a Netzsch 449 Jupiter synchronous thermal analyzer. To study the morphology and composition of the products, the methods of X-ray phase analysis, optical and scanning electron microscopy, and X-ray fluorescence microanalysis were used. The devices used were a Rigaku Ultima IV X-ray diffractometer and a scanning electron microscope with a Jeol JSM-7001F. The mechanisms of thermal decomposition of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates were suggested. For a more accurate determination of the composition of the synthesis products of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates and for a more accurate description of the processes of thermal decomposition of these salts, the corresponding aromatic carboxylic acids were also thermally decomposed. The appendix to the article presents thermograms of manganese(II), cobalt(II), nickel(II), and copper(II) aromatic carboxylates.

PLASMA DISCHARGE IN LIQUID MEDIA UNDER THE EFFECT OF ULTRASOUND FOR THE SYNTHESIS OF FILLERS FOR POLYMER COMPOSITES WITH ENHANCED MECHANICAL STRENGTH AND GAS PERMEABILITY

Zinc oxide nanoparticles were synthesized using a plasma discharge method under the effect of ultrasonic cavitation, and films of a polymer composite material were obtained and studied. Comparatively, the mixture of zinc oxide nanoparticles with planar graphene oxide nanostructures were also used as a filler. Using melt compounding technology, composite materials were obtained in the form of thin films consisting of the copolymer of ethylene and vinyl acetate and nanoparticles of zinc oxide and graphene oxide. The obtained samples of composite materials were examined by X-ray phase analysis, X-ray fluorescence analysis, and scanning electron microscopy. The physical, mechanical, and gas transport properties of composite films made of polymers filled with nanoparticles were studied: permeability measurements were carried out for carbon dioxide and helium gases.

ВЫПУСК ОПЫТНО-ПРОМЫШЛЕННЫХ ПАРТИЙ КРИОЛИТА С ИСПОЛЬЗОВАНИЕМ ХЛОРИДА И ГИДРОКСИДА НАТРИЯ И ИХ ИСПЫТАНИЯ ПРИ ПРОИЗВОДСТВЕ АЛЮМИНИЯ

The paper presents the results of pilot batch production of cryolite using sodium chloride and sodium hydroxide by hydrochemical method, physical and chemical studies of the obtained products, as well as their testing in aluminium electrolysers with measurements of technological parameters before and after use. The conducted studies have shown that the process of production of a pilot batch of cryolite by hydrochemical method from hydrofluoric acid using aluminium hydroxide, sodium chloride and sodium hydroxide solutions proceeds at a temperature of 25 °C for 30-45 min. In this case, the yield of cryolite according to the first embodiment using sodium chloride is more than 80 %, since during the reaction a side hydrochloric acid is formed, which dissolves more than 15 % of the cryolite. When sodium hydroxide is used, the process proceeds similarly to the first variant with an increase in cryolite yield of more than 90%. According to pilot tests, the first variant produced 600 kg of cryolite and the second variant produced 620 kg of cryolite. The reliability of the process of cryolite production with the use of sodium chloride and hydroxide was confirmed by chemical and X-ray phase analyses using the modernised Dron-2 unit. It was found that the analysed samples correspond to the reference cryolite, indicating the interaction of sodium chloride and sodium hydroxide with fluoroaluminium acid. Also the obtained synthetic products have successfully passed pilot tests in aluminium electrolysers of JSC "TALCO" with control of technological parameters. On the basis of conducted researches the basic technological scheme of cryolite production by hydrochemical method with application of hydrofluoric acid, aluminium hydroxide, sodium chloride and hydroxide was developed. As a result of the research it was found out that the technology of cryolite production with the use of sodium chloride and hydroxide is easy to implement and cost-effective due to low energy consumption of production and the use of local mineral raw materials.

Структура и прочность пористых материалов на основе порошков карбида титана разной дисперсности

Materials with porosity from 67.5 to 82.5 % were obtained from mixtures of titanium carbide powders and ammonium bicarbonate blowing agent by sintering in vacuum at temperatures of 1300 – 1500 °C. X-ray phase analysis of porous materials found that the crystal lattice parameter decreases with increasing sintering temperature. This indicates a decrease in the content of bound carbon C/Ti in titanium carbide. As a result of a comparative study of the obtained according to bending test strength characteristics of materials synthesized from nano- and submicron titanium carbide powders, it was found that the strength have close values. Ultimate bending strength are in the range of 2.6 – 18.1 MPa. As the porosity of the material increases, the tensile strength decreases. Fracture is brittle. In the fracture of materials obtained from titanium carbide nanopowder, destruction is observed both along the body and along the grain boundaries regardless of the sintering temperature. In materials obtained by sintering submicron titanium carbide powder at 1500 °C, the destruction occurs predominantly along the body of the grains. It has been found that under the same sintering conditions, the density of the porous material made of titanium carbide nanopowder is higher than that of the material made of submicron powder.

ПОЛУЧЕНИЕ И ИССЛЕДОВАНИЕ СВОЙСТВ ТВЕРДЫХ ДИСПЕРСИЙ БЕНЗОЙНОЙ КИСЛОТЫ С ПОЛИВИНИЛПИРРОЛИДОНОМ К-12

As a result of widespread use of antibiotics, a large number of microbial strains have acquired resistance to drugs of this group. Benzoic acid is widely used in many industries: in the food industry as a preservative, in medicine and veterinary medicine as an antiseptic agent. Despite the effectiveness of benzoic acid as an antibacterial component, its use is limited by its low solubility in water. Currently, an actual direction in chemical technology is the direction of modifying the properties of biologically active substances by obtaining their multicomponent compositions with improved properties. One of the technological methods to increase solubility of poorly soluble biologically active substances is obtaining solid dispersions of these substances. There are no data on the introduction of benzoic acid into the composition of solid dispersions. This served as a prerequisite for the development of solid dispersions of benzoic acid with subsequent study of their properties. The aim of this work was to obtain and study the properties of solid dispersions of benzoic acid with polyvinylpyrrolidone K 12. The solubility of benzoic acid from solid dispersions based on polyvinylpyrrolidone K 12 was studied. The application of this technological technique increased the solubility of benzoic acid by 3.5 times. The studies carried out by means of X-ray phase analysis, IR spectroscopy and determination of particle sizes by dynamic light scattering method allow us to assume that an increase in the solubility of benzoic acid from its solid dispersions is caused by obtaining a system with its highly dispersed crystalline phase in polyvinylpyrrolidone K 12, solubilising effect of the latter and formation of colloidal solution of benzoic acid when its solid dispersion is dissolved.

Study of Optical Properties and Structural Features of Object using the X-ray Phase Contrast Method

Study of Optical Properties and Structural Features of Object using the X-ray Phase Contrast Method

Physico-chemical research of the processes of hydration of cements

The activating effect of phosphoanhydrite on cement hydration is strongly supported by the results obtained from various physico-chemical analyses, including IR spectroscopy, X-ray phase analysis, and differential thermal analysis. IR spectroscopy revealed significant differences in the hydration products of cement with and without phosphoanhydrite. The presence of phosphoanhydrite led to distinct absorption bands in the IR spectra, indicating a higher concentration of Portland cement hydrate compounds and calcium the activated cement. This observation suggests that hydrosilicates in phosphoanhydrite plays a vital role in promoting the formation of these hydration products, leading to enhanced cement activation.X-ray phase analysis further confirmed the activating effect of phosphoanhydrite. The diffraction patterns of the hydrated cements showed a remarkable increase in the analytical lines corresponding to Ca(OH)2 when phosphoanhydrite was present. This indicates a higher content of this phase in the activated cement, reinforcing the notion that phosphoanhydrite contributes to the accelerated hydration process.Differential thermal analysis provided additional evidence of the activating effect of phosphoanhydrite. The DTA curves exhibited higher hydration levels for the cement activated with phosphoanhydrite compared to the control cement. This was indicated by an increased percentage of bound water and a greater mass loss at 140°C, demonstrating the more extensive hydration of the activated cement.Taken these physico-chemical analyses consistently demonstrate the activating effect of phosphoanhydrite on cement hydration. The unique properties of phosphoanhydrite facilitate the formation of hydration products, such as Portland cement hydrate compounds and calcium hydrosilicates, leading to an accelerated and more efficient hydration process.

Molten salt-shielded synthesis of Ti3AlC2 as a precursor for large-scale preparation of Ti3C2Tx MXene binder-free film electrode supercapacitors.

MXenes are a group of two-dimensional materials that are promising for many applications, including as film electrode supercapacitors. When synthesizing such materials, special attention is paid to the conditions for obtaining the MAX phase, the chemical, morphological and structural features of which determine the functional properties of the final product. In this study, the Ti3AlC2 precursor is proposed to be obtained using a technologically simple and accessible method of synthesis in molten salt. This method allows reducing the reaction temperature and creating an antioxidant atmosphere. Ti3C2Tx MXene electrode films are produced by the easily scalable blade coating method without a binder. The synthesized materials were studied by X-ray phase analysis and scanning electron microscopy. Electrochemical testing of Ti3C2Tx film electrodes was carried out in a three-electrode configuration in aqueous solutions of 1M H2SO4, 6M KOH, 1M LiOH and 1M Na2SO4 electrolytes. The maximum specific capacity value for Ti3C2Tx MXene binder-free film electrode supercapacitors is obtained in 1M H2SO4 electrolyte (480 F g-1 at a scan rate of 1 mV s-1). The simple, low-cost and scalable production technology and promising electrochemical characteristics of the Ti3C2Tx MXene binder-free film electrode make it an excellent candidate for new-generation supercapacitors.

Получение и исследование плёнок нитрида алюминия

Aluminum nitride films were produced on substrates of quartz, glass, aluminum and steel by reactive RF magnetron sputtering and ion–beam processing. The thickness of aluminum nitride coatings decreases with increasing current of ion-beam processing from 1700 to 650 Å. According to the energy dispersive analysis of films on steel and aluminum substrates, the nitrogen concentration increases with increasing current of ion-beam treatment. The X-ray phase analysis of the resulting films has shown that aluminum nitride films are X-ray amorphous. Aluminum nitride films are highly transparent. An increase in the refractive index of the films from 1.74 to 1.80 (for wavelength λ = 586 nm) and band gap from 5.32 to 5.61 eV with increasing current of ion-beam treatment was revealed. The band gap and refractive index values correlate satisfactorily with the literature data for aluminum nitride. Electron and atomic force microscopy has shown that aluminum nitride films are homogeneous and smooth. Roughness decreases with the introduction of ion-beam processing. It is found that the microhardness of the films deposited on aluminum substrates has increased by a factor of 1.5, and a 2.2 fold increase has been observed for the microhardness of the films deposited on steel substrates t. The maximum increase in microhardness is observed at the current of ion-beam processing of 40 mA.

Влияние модифицирования йодом и термической постобработки на структуру и электропроводность оксида графена

An original technique for modifying graphene oxide with iodine has been developed. It is shown that when graphene oxide is treated with iodine, oxygen-containing groups are removed from the surface of graphene planes, which improves the electrically conductive properties of the material. The change in the structure and electrical conductivity of the modified graphene oxide, depending on the concentration of iodine, has been studied. According to Raman spectroscopy data, it can be seen that the composition of the modified materials includes molecular complexes of iodine I3– and I5–. Changes in the structure of the crystal lattice of iodine-modified graphene oxide films were studied using X-ray phase analysis. According to IR spectroscopy, the effect of iodination on the change in the qualitative composition of functional groups in the material was analyzed. The specific electrical conductivity of graphene oxide as a result of modification increases from 9.6·10–10 S/cm for the original material to 3.3·10–7 S/cm for the material treated with an isopropanol solution containing 1 wt. % I2 relatively dry graphene oxide. The additionally modified films were heat treated at 80 °C for 2 hours. The resulting changes in the structure of the material are analyzed and an increase in electrical conductivity by one or two orders of magnitude is shown.

Study of Shomishkul kaolin for producing ceramic materials

The article discusses the results of research studies of kaolins from the Shomishkul deposit in Karakalpakstan using chemical-mineralogical and X-ray phase analyses. As a result of the tests, it was established that samples of clay minerals from the studied deposits can be used as the main raw material component for the production of ceramic materials, which helps to expand the raw material base for the production of ceramic materials for construction purposes.

Single shot machine learning based phase retrieval for the X-ray phase imaging

Single shot machine learning based phase retrieval for the X-ray phase imaging

Электрохимические свойства углеродных материалов с высоким содержанием азота

The development and improvement of materials for storing electrical energy is important for the development of renewable energy technology. Some of the most suitable devices for storing electrical energy are supercapacitors, since they are able to withstand high charge and discharge currents, and they have a large number of recharge cycles. The characteristics of double-layer supercapacitors (DLSC) largely depend on the materials of the electrode on which the electrical double layer is formed. The most promising materials for the production of DLSC are carbon-based materials, such as activated carbons, soot, fullerenes, nanotubes, and graphene. It is possible to improve the characteristics of existing materials by increasing their electric conductivity, electrolyte wettability, and increasing the specific surface area. Doping carbon materials with nitrogen atoms makes it possible to solve these problems in many ways, including reducing their electric resistance. One of the ways to obtain nitrogen-rich carbon materials is the slow thermolysis of a mixture of coal tar pitch and melamine. This method makes it possible to obtain single-phase carbon materials with the pitch mass fraction up to 22 wt %. Electron microscopy methods have shown that with increasing nitrogen concentration, materials become loosened. With the use of X-ray phase analysis it has been shown that the resulting materials have a layered structure similar to graphite. Using the XPS method, it has been established that nitrogen atoms are embedded in the structure of the graphite sheet. The resulting materials are dominated by nitrogen atoms in the pyridine configuration. The electrochemical properties of the resulting materials have been studied in an electrochemical cell, which is a prototype of DLSC. The material with the nitrogen concentration of 4.2 wt % has the greatest capacity. The characteristics of the resulting DLSC have been compared with a commercially produced capacitor with a capacity of 220 mF and have shown their great similarity.

PHYSICO-CHEMICAL PROCESSES OF ALKALINE ACTIVATION OF SILICA DURING HEAT TREATMENT IN THE SIO2-NaOH-H2O SYSTEM

The physicochemical processes during alkaline activation of the SiO2-NaOH-H2O system with crystalline silica have been investigated. The studies were carried out using thermogravimetric, X-ray phase analysis methods and IR spectroscopy data. Compositions with different silicate modulus (SiO2/Na2O 4-7), the amount of the introduced silica fume (10-30%) in substitution of marshalite and the concentration of sodium hydroxide solution (30-60 wt.%) are considered. According to the results of the study, the reactions of interaction of the components and a model of phase transformations in the composition when it is heated to 850 °C are proposed. At the stage of interaction of the components (30-130 °C), hydration processes occur with the formation of sodium hydrosilicate Na2SiO3(OH), with on the surface of which a layer of crystallohydrate water and a water layer to be formed without formation of free water. When the composition is heated to temperatures of 130-300 °С the water layer and then the crystallohydrate water are removed. The removed water interacts with unreacted silica and forms hydrated forms of silica. Upon further heating to temperatures of 310-800 °C, OH groups are removed from sodium hydrosilicates and hydrated forms of silica and it turns into anhydrous silicates. Heating the composition to 850 °C leads to the formation of a pyroplastic mass from a eutectic melt (Na2O·2SiO2–SiO2) and residual silica. The two-stage mechanism of formation of a porous frame is established at the stage of decomposition of sodium hydrosilicate crystallohydrates (80-200 °C) and at the stage of melt foaming at high temperatures (790-850 °C). Foaming occurs due to the removal of water vapor (80-200 °C) and the expansion of the volume of gases (790-850 °C) in the porous structure formed at the first stage of foaming. The developed compound of the high-modulus composition (SiO2/Na2O 5,7) is a basis to obtain a porous glass composite using a two-stage alkaline technology with the introduction of additional oxides that increase chemical resistance. The composition includes the following components, wt.%: marshalite – 50, silica fume – 23, sodium hydroxide – 16, water – 11.