High-temperature Process Research Articles

Effect of Rare Earth Ion Substitution on Phase Decomposition of Apatite Structure.

The paper describes an investigation of phase decomposition of apatite lattice doped with rare earth ions (cerium, samarium, and holmium) at temperatures ranging from 25-1200 °C. The rare-earth ion-doped apatite minerals were synthesized using the sol-gel method. In situ high-temperature powder X-ray diffraction (XRD) was used to observe the phase changes and the lattice parameters were analyzed to ascertain the crystallographic transformations. The expansion coefficient of the compounds was determined, and it was found that the c-axis was the most expandable due to relatively weak chemical bonds along the c-crystallographic axis. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to examine the decomposition properties of the materials. Due to rare earth ion doping, the produced materials had slightly variable decomposition behaviour. The cerium and samarium ions were present in multiple oxidation states (Ce3+, Ce4+, Sm3+, Sm2+), whereas only Ho3+ ions were observed. Rare earth ion substitution affects tri-calcium phosphate proportion during decomposition by regulating concentrations of vacancies. X-ray photoelectron spectroscopy (XPS) analysis indicated that cerium and samarium ion-doped apatite yielded only 25 % tricalcium phosphate during decomposition. This finding advances our understanding of apatite structures, with implications for various high-temperature processes like calcination, sintering, hydrothermal processing, and plasma spraying.

Organic Passivation-Enhanced Ferroelectricity in Perovskite Oxide Films.

Perovskite oxides and organic-inorganic halide perovskite materials, with numerous fascinating features, have been subjected to extensive studies. Most of the properties of perovskite materials are dependence on their ferroelectricity that denoted by remanent polarization (Pr). Thus, the increase of Pr in perovskite films is mainly an effort in material physics. At present, commonplace improvement schemes, i.e., controlling material crystallinity, and post-annealing by using a high-temperature process, are normally used. However, a simpler and temporal strategy for Pr improvement is always unavailable to perovskite material researchers. In this study, an organic coating layer, low-temperature, and vacuum-free strategy is proposed to improve the Pr, directly increasing the Pr from 36 to 56µCcm-2. Further study finds that the increased Pr originates from the suppression of the oxygen defects and Ti defects. This organic coating layer strategy for passivating the defects may open a new way for the preparation of higher-performance and cost-effective perovskite products, further improving its prospective for application in the electron devices field.

Thermal insulating performance of thermal protection system with sandwich structure based on Al2O3/SiC composites aerogels

The thermal protection system (TPS) are an indispensable component of aerospace vehicles that can withstand harsh aerothermal conditions during the reentry process. Recently, the sandwich structures of TPS have been widely used to meet the development trend of structure-performance integrated design. In this study, a TPS with a sandwich structure based on Al2O3 aerogels reinforced by SiC nanowire are proposed. The Al2O3/SiC composites aerogels are synthesized via the low-cost method, including sol-gel, freeze-casting and high-temperature treatments processes. The microstructure, phase composition, thermal insulation and compressive resistance of composite aerogels at different SiC nanowires content are investigated in detail. The resulting Al2O3/SiC composites aerogels, exhibiting better compressive strength and thermal stability with the increase of SiC nanowires content, achieve the purpose of being an excellent thermal insulation material of TPS at high temperature. The characterization of thermal insulating performances of the TPS are also evaluated by the oxyacetylene torch testing. The TPS shows extraordinary high-temperature resistance, and the average linear ablation rate and mass ablation rate are 0.0032 mm/s and 0.005 g/s, respectively, which can satisfy the requirement of TPS for aerospace vehicles under ultra-high temperature conditions.

Morphology Control and Mechanism of Different Bath Systems in Cu/SiCw Composite Electroplating.

With the rapid development of electronic technology and large-scale integrated circuit devices, it is very important to develop thermal management materials with high thermal conductivity. Silicon carbide whisker-reinforced copper matrix (Cu/SiCw) composites are considered to be one of the best candidates for future electronic device radiators. However, at present, most of these materials are produced by high-temperature and high-pressure processes, which are expensive and prone to interfacial reactions. To explore the plating solution system suitable for SiCw and Cu composite electroplating, we tried two different Cu-based plating solutions, namely a Systek UVF 100 plating solution of the copper sulfate (CuSO4) system and a Through Silicon Via (TSV) plating solution of the copper methanesulfonate (Cu(CH3SO3)2) system. In this paper, Cu/SiCw composites were prepared by composite electrodeposition. The morphology of the coating under two different plating liquid systems was compared, and the mechanism of formation of the different morphologies was analyzed. The results show that when the concentration of SiCw in the bath is 1.2 g/L, the surface of the Cu/SiCw composite coating prepared by the CuSO4 bath has more whiskers with irregular distribution and the coating is very smooth, but there are pores at the junction of the whiskers and Cu. There are a large number of irregularly distributed whiskers on the surface of the Cu/SiCw composite coating prepared with the copper methanesulfonate (Cu(CH3SO3)2) system. The surface of the composite is flat, and Cu grows along the whisker structure. The whisker and Cu form a good combination, and there is no pore in the cross-section of the coating. The observation at the cross-section also reveals some characteristics of the toughening mechanism of SiCw, including crack deflection, bridging and whisker pull-out. The existence of these mechanisms indicates that SiCw plays a toughening role in the composites. A suitable plating solution system was selected for the preparation of high-performance Cu/SiCw thermal management materials with the composite electrodeposition process.

Melting heat transfer of a quadratic stratified Jeffrey nanofluid flow with inclined magnetic field and thermophoresis

Recently, researchers are facing great challenges to form the homogeneous solutions of various liquids at biomedical and industrial levels. Such homogeneous solutions can be controlled through stratification phenomenon directly which is ignored by the researchers in the existing literature specifically quadratic stratification and melting heat mechanism which is valid only for higher temperature processes. Thus, to form the homogeneous and stable liquid solutions for various industrial processes, we investigate the melting heat phenomenon in quadratic stratified Jeffery Nano fluid flow deformed due to linearly stretching sheet along with stagnation point. Inclined constant magnetic field is implemented on the fluid through an arbitrary angel. Characteristics of heat and transportations are disclosed through viscous dissipation, Brownian motion and thermphoresis. Temperature and concentration of the surrounding fluids are assumed higher than the stretching surface. The resultant governing equations are reduced to ordinary differential equations through proper transformations. Convergent analytical series solutions are computed via homotopic approach. Impact of various emerging parameters on temperature, velocity and concentration fields are illustrated and discussed comprehensively. Sherwood and Nusselt numbers and drag force are scrutinized mathematically, physically and graphically. It is analyzed from the study that (i) dominant melting reduces the temperature field (ii) higher thermal and solutal stratification decay the temperature and concentration fields respectively (iii) higher thermophoresis enhances the temperature field. Further, it is concluded that stable and homogeneous solutions may be made by increasing melting and reducing stratification phenomena. This study will help us to provide actual amount of heat for heating processes in industries and biomedicine which is the basic requirement for excellent quality of products.

CONCEPT OF MICROBIOLOGICAL GRAPH OF FEED AND FOOD PRODUCTION

Compound feeds are favorable environments for microorganisms, namely bacteria and fungi. Both groups contain nonpathogenic, opportunistic and pathogenic members. Bacteria can cause infections, and fungi can cause mycotoxicoses, so controlling microbial contamination of feed is of great importance. Sources of microbial contamination of compound feed include both raw materials and the production environment: air, surfaces, equipment, and the hands and clothing of employees. As raw materials and pre-products move through production lines, they undergo certain processes that can either reduce or increase microbial contamination. The reducing processes include grain dehulling and high-temperature processing (moisture and heat treatment, conditioning, extrusion, expansion, drying of minerals, granulation), while the increasing processes include making preliminary mixtures, grinding, dosing and mixing, and the production of grits. In dosing and mixing, the contribution of each component is determined by its dose and has a two-way effect: the component contributes its microbiota, but its mass dilutes the mixture. The sequence of these processes represents a certain dynamics of microbial burden, which will result in the contamination level of the finished product lower or higher than in the initial raw material. This sequence can be represented as a microbiological graph, the vertices of which are the positive or negative contributions of the processes to the microbiological burden of the material. And the system of such vertices can be represented as a simple mathematical equation. Creating microbiological graphs for individual production lines or for the manufacture as a whole can help to understand the microbiological dynamics in a material or product and apply appropriate corrective measures to prevent microbiological hazards in the final product. This paper proposes a method of making a microbiological graph with two types of vertex designations for the IV generation compound feed production, as well as a mathematical apparatus for calculating the vertices of the graph.

Mechanical properties of Q235 and 20# steel after CO2 fire extinguishing treatment

The carbon dioxide fire extinguishing process can produce temperatures as low as −80 °C. However, the effect of rapid cooling and ultralow temperatures on the properties of steel is not yet clear. To accurately evaluate the effect of CO2 fire extinguishing on the mechanical properties of crude oil tank walls (Q235-B) and accessory and pipe materials (20#), this study employs tensile, Charpy impact, and bending tests to analyze the changes in the primary mechanical properties of Q235-B and 20# steels after three pretreatments: high-temperature burning, CO2 spraying, and CO2 fire extinguishing. The results of the study show that 1) the high-temperature burning process and short-term spraying of CO2 after fire may damage the mechanical properties of steel; 2) the rapid use of CO2 spraying after fire does not damage the mechanical properties of Q235-B or 20#; and 3) the three pretreatments investigated have little effect on the bending properties of all the specimens.

Construction of CeO2/Co/CNT electrocatalyst with adsorption-catalytic synergistic effect for the suppression of the shuttle effect in lithium sulfur batteries

Lithium‑sulfur batteries are recognized as a strong candidate for the next generation of high capacity density batteries. However, the shuttle effect of soluble polysulfide intermediates during the charging and discharging process of lithium‑sulfur batteries leads to a rapid decrease in their electrochemical performance, thus limiting their practical applicability. In this study, the rare earth element cerium (Ce) was introduced into a bimetallic electrocatalyst to modify the separator in order to inhibit the shuttle effect for soluble polysulfide intermediates in lithium‑sulfur batteries. The CeO2/Co bimetallic electrocatalyst composite with in situ-grown carbon nanotubes (CeO2/Co/CNT) was obtained by a simple single-step high-temperature carbonization process. The strong polarity of CeO2 in CeO2/Co/CNT could trap soluble polysulfide intermediates onto the composite surface, synergizing with Co to further enhance the catalytic efficiency of soluble polysulfide intermediates into insoluble Li2S. Simultaneously, CNTs in CeO2/Co/CNT provided fast Li+ and electron transfer channels for the efficient catalytic conversion of soluble polysulfide intermediate. The initial discharge specific capacity of lithium‑sulfur batteries assembly by using CeO2/Co/CNT modified separator presented an initial discharge specific capacity of 1377.05 mAh g−1 at 0.1 C, and 676.8 mAh g−1 after 200 cycles at 1 C, demonstrating a significant performance improvement compared to blank control battery.

RESEARCH OF HEAT RESISTANCE OF CARBON-CARBON COMPOSITE MATERIALS WITH PROTECTIVE COATINGS OBTAINED USING FUNCTIONALLY ACTIVE CHARGES

This study focuses on the development of protective coatings for carbon-carbon composite materials (CCСM) used in high-temperature processes in aerospace engineering. CСCM have limitations due to their susceptibility to oxidation, erosion, and burnout in gas streams. Our research is aimed at creating protective coatings using functionally active charges (FAC) obtained under non-stationary temperature conditions and improving the performance of composites. The aim of our study is to identify the optimal compositions of powders for chromium-alloyed protective coatings using functionally active charges to increase the heat resistance of the working surface. We analyzed various methods of obtaining protective coatings, including chemical-thermal and liquid-phase saturation methods, to find out their peculiarities in interaction with the CCСM matrix and changes in their mechanical properties. In addition to the traditional methods, we have investigated the method of saturating the surface with a solid phase in an active gas environment using FAС, which are obtained under non-stationary temperature conditions. This method provides high quality coatings, reduces processing time and makes it possible to work at high temperatures depending on the composition of the spray coatings. Much attention was paid to the problem associated with chemical interaction and formation of carbide phases, which are important for ensuring the stability of coatings under high temperature conditions. Experimental studies include a factorial experiment to determine the compositions of powder mixtures that provide high heat resistance. Various independent variables, such as the content of chromium, silicon, titanium, and aluminum, were considered, taking into account their influence on the physical and mechanical properties of coatings. Particular attention was paid to the optimization of the parameters of thermal autoinitiation of the functionally active charge under process conditions. Regression equations are presented to evaluate the dependence of the wear resistance of coatings on the autoinitiation parameters and the content of alloying elements. The analysis of the study results includes the construction of three-dimensional graphical dependencies for optimizing the composition of powdered CBA in the Cr-Al-Ti and Cr-Al-Si systems. In practice, chromium-aluminum-siliconized coatings obtained under isothermal conditions, when tested for heat resistance, have a more porous surface through which oxygen penetrates to the surface of the HCCM. Compared to the coatings obtained using FAS, the heat resistance is 1.5-1.7 times higher, which can be explained by the higher concentration of chromium, aluminum, silicon, and titanium, which contribute to the formation of protective oxide membraness. The low-porosity surface of the coatings obtained using functionally active layers prevents oxygen from entering the material, contributing to the formation of oxide protective membranes such as SiO2, TiO2, Cr2O3, Al2O3.

Numerical Investigation of Shell-Side Flow Behavior and Vapor Distribution in Waste Heat Boilers.

Shell-and-tube waste heat boilers (STWHBs) are essential in the recovery of waste heat from high-temperature industrial processes. Kettle-type STWHBs are known to experience failures due to hold-up of steam, a significant concern in the industry. Multiphase computational fluid dynamics (CFD) simulations are used to study the effect of tube layout on the steam hold-up of an industrial-scale STWHB. Different design specifications are simulated including tube layout, heat flux, and pitch to predict steam hold-up performance and analyze thermo-hydrodynamic phenomena within the tube bundle. Simulation results show that, for similar tube bundle shape and size, 45° rotated square tube bundle layouts perform better, with respect to steam hold-up, than the square and triangle layouts for a range of heat flux duties. It is found that steam hold-up increases linearly with increasing heat flux and decreasing tube pitch, for the conditions simulated. The turbulent kinetic energy of the bubbly flow is greatly influenced by increasing phase fraction. Visualizations of the flow of water and steam within and around the tube bundle show that there is a vertical flow deviation for both staggered tube patterns (rotated square and triangle). These results motivate further multiphase CFD-based study of the thermo-hydrodynamics of STWHBs for improved understanding, retrofit, and new designs.

Получение покрытий с высокой инфракрасной излучательной способностью

Introduction. One of the promising modern methods of coating formation is detonation gas dynamic sputtering. Coatings obtained by this method have high adhesion to the substrate, dense structure and specified functional properties. Development of technology for obtaining functional coatings with high emission coefficient in the infrared range is an urgent need for the development of high-temperature industrial processes and technologies. High-temperature industrial processes consume a large amount of energy, so improving the energy efficiency of industrial equipment is considered as one of the ways to overcome the ever-growing energy crisis. To this end, coatings with high infrared emissivity have been developed for industrial furnaces. These coatings are usually applied to the furnace walls, which significantly improves energy efficiency by increasing heat transfer from the heat-emitting surfaces of the furnace. The purpose of the work is to obtain coatings with high emission indices in the infrared range for further recommendation of its use in baking ovens of Shebekinsky machine-building plant. Methods for studying coating specimens obtained by detonation gas-thermal method: scanning electron microscopy, X-ray phase analysis, energy dispersive analysis, infrared spectroscopy. Results and discussion. The microstructure, phase composition, emissivity and thermal cycling resistance of Fe2O3; Al2O3 + 10 % Fe2O3; Ti + 10% Fe2O3 coatings obtained by detonation gas-dynamic powder spraying are investigated in this work. The results of the study showed that the obtained coatings have a dense structure, increased emissivity and resistance to thermal treatment cycles, as a result of which the structure of the crystal lattice of the coatings does not change.

The enhanced mechanical properties for Hf6Ta2O17 thin film through component segregation

With outstanding thermal and mechanical properties, Hf6Ta2O17 emerges as an ideal candidate for next-generation thermal barrier coatings (TBC) material. However, high-temperature process during TBC fabrication will inevitably lead to Ta2O5/HfO2 component segregation because large differences in vapor pressure. In this paper, Hf6Ta2O17 polycrystalline film with different Ta2O5/HfO2 component was prepared on sapphire substrate by sol-gel method through spin coating. Morphological analysis indicates the excessive Ta2O5 can reduce the porosity in Hf6Ta2O17 thin film through eutectic process, while excessive HfO2 will lead to a worse morphology and smaller average grain size. Nanoindentation reveals that component segregation of excessive Ta2O5/HfO2 could both be used to strengthen of Hf6Ta2O17 through different mechanisms. In addition, a higher elastic recovery rate in excessive Ta2O5 system indicates Ta2O5Hf6Ta2O17 eutectic system could accelerate energy dissipation and further enhance the toughness for Hf6Ta2O17. This work provides a deep insight into the strengthening mechanism of ceramics Hf6Ta2O17 with component segregation and paves the way to design of next-generation TBCs.

In situ formation of silver nanoparticles within labradorite mineral crystals exhibiting third-order nonlinearity

Silver nanoparticles are cost-effective plasmonic materials for the nonlinear optics, but the applications suffer incompatibility with the matrices. This study explores the in situ formation of silver nanoparticles within the crystalline matrix of labradorite minerals. The methodology involves a high-temperature diffusion process, enabling the nucleation and growth of silver nanoparticles directly within the labradorite crystal lattice. Characterization through spectroscopic and microscopic techniques reveals the successful formation of silver nanoparticles with a diameter of 8.40 ± 4.32 nm, exhibiting notable surface plasmonic resonances absorption at 414 nm. Additionally, the nonlinear optical property of the resulting material is investigated through Z-scan experiments. The third-order nonlinear optical susceptibility β at 400 nm was estimated to be 5.0 × 10−12 m/W. This research not only advances our understanding of nanoscale phenomena within mineral crystals but also underscores their potential applications in nonlinear optical devices and related fields.

Improvements in Resistive and Capacitive Switching Behaviors in Ga2O3 Memristors via High-Temperature Annealing Process.

This study investigates the effect of a high-temperature annealing process on the characteristics and performance of a memristor based on a Ag/Ga2O3/Pt structure. Through X-ray diffraction analysis, successful phase conversion from amorphous Ga2O3 to β-Ga2O3 is confirmed, attributed to an increase in grain size and recrystallization induced by annealing. X-ray photoelectron spectroscopy analysis revealed a higher oxygen vacancy in annealed Ga2O3 thin films, which is crucial for conductive filament formation and charge transport in memristors. Films with abundant oxygen vacancies exhibit decreased set voltages and increased capacitance in a low-resistive state, enabling easy capacitance control depending on channel presence. In addition, an excellent memory device with a high on/off ratio can be implemented due to the reduction of leakage current due to recrystallization. Therefore, it is possible to manufacture a thin film suitable for a memristor by increasing the oxygen vacancy in the Ga2O3 film while improving the overall crystallinity through the annealing process. This study highlights the significance of annealing in modulating capacitance and high-resistive/low-resistive state properties of Ga2O3 memristors, contributing to optimizing device design and performance. This study underscores the significance of high-temperature annealing in improving the channel-switching characteristics of Ga2O3-based memristors, which is crucial for the development of low-power, high-efficiency memory device.

Enhanced Photocatalytic Hydrogen Evolution of In2S3 by Decorating In2O3 with Rich Oxygen Vacancies.

The hydrogen (H2) evolution rates of photocatalysts suffer from weak oxidation and reduction ability and low photogenerated charge carrier separation efficiency. Herein, by combining band-gap structure optimization and vacancy modulation through a one-step hydrothermal method, In2O3 containing oxygen vacancy (Ov/In2O3) is simply introduced into In2S3 to promote photocatalytic hydrogen evolution. Specifically, the change in the sulfur source ratio can induce the coexistence of Ov/In2O3 and In2S3 in a high-temperature hydrothermal process. Under light irradiation, In2S3@Ov/In2O3-0.1 nanosheets hold a remarkable average H2 evolution rate up to 4.04 mmol g-1 h-1, which is 32.14, 11.91, and 2.25-fold better than those of pristine In2S3, In2S3@Ov/In2O3-0.02, and In2S3@Ov/In2O3-0.25 nanosheets, respectively. The ultraviolet-visible (UV-vis) diffuse reflectance and photoluminescence (PL) spectra reveal that the formation of Ov/In2O3 in In2S3 optimizes the band-gap structure and accelerates the migration of the photogenerated charge carrier of In2S3@Ov/In2O3-x nanosheets, respectively. Both the enhancement of oxidation and reduction ability and photogenerated charge carrier separation ability are responsible for the remarkable improvement in photocatalytic H2 evolution performance. This work provides a new strategy to prepare a composite of metal sulfide and metal oxide through a one-step hydrothermal method.

Enhancing mechanical and rheological properties of HDPE films through annealing for eco-friendly agricultural applications

Abstract A composite of high-density polyethylene/ultra-high molecular weight polyethylene (HDPE/UHMWPE) was synthesized via a high-temperature melting process. We specifically examined the effects of annealing on the morphological and rheological properties of the composite. Using scanning electron microscopy and advanced rotational rheometry, we determined that annealing notably alters the composite’s microstructure, with a reduction in pronounced features post-treatment. Rheologically, UHMWPE content significantly enhanced mechanical properties, particularly in storage modulus (G′), loss modulus (G″), and complex viscosity (|η*|), which aligned with scaling law principles. Our findings highlight a distinct improvement in mechanical properties post-annealing, underscoring the potential of UHMWPE in enhancing polymer composite performance. The scaling laws relating G′, G″, and |η*| with UHMWPE were identified as follows: (1) pre-c e: G′ ∼ c 0.2, g″ ∼ c 0.07, |η*| ～ c0.07 and (2) post-c e: G′ ∼ c 1.20, g″ ∼ c 0.6, |η*| ∼ c 0.64, with a forward shift in c e noted after annealing. The addition of UHMWPE significantly enhanced the system’s properties, particularly after annealing. This study offers crucial insights into optimizing HDPE plastic films for enhanced durability and sustainability, ideally suiting them for eco-friendly agricultural uses.

Diffusion behavior of Cr and V elements in the 50CrVA steel under high-temperature oxidation and surface treatment processes

Diffusion behavior of Cr and V elements in the 50CrVA steel under high-temperature oxidation and surface treatment processes

Вивчення високотемпературного тепломасообміну двофракційних газозависів і поодиноких вуглецевих частинок в нагрітому повітрі

In the work, the regularities of high-temperature heat-mass exchange in two-fraction gas suspensions of carbon particles in heated air are studied. These studies are relevant for predicting high-temperature processes in combustion chambers and determining the main characteristics of these processes: induction period, time and temperature of combustion, critical parameters of ignition and extinction. Physico-mathematical modeling of the problem is carried out on the basis of the equations of heat and mass transfer and chemical kinetics for the components of the gas suspension, taking into account the molecular-convective and radiation mechanisms of heat transfer. The characteristics of ignition, burning, and extinction of a two-fraction gas suspension of carbon particles with equal mass concentrations of small (60 μm) and large (120 μm) fractions in the temperature range of 1100 ÷ 1500 K were studied; a comparison was made with the characteristics for single particles of the corresponding diameters. It has been proven that when the gas temperature decreases, the induction period of the fine fraction can exceed the induction period of the large fraction, while the combustion temperature of small particles becomes lower than the combustion temperature of large particles. At high gas temperatures (1400K, 1500K), the situation changes to the opposite. The critical ignition and extinction parameters of two-fraction gas suspensions (gas temperatures, particle diameters) were found.

RESEARCH ON THE RELATIONSHIP BETWEEN THE THICKNESS AND THE STRUCTURAL CONDITION OF ROLLED METAL FROM LOW-CARBON LOW-ALLOY STEEL 10G2FB

When choosing steels for the design of high-rise and long-span buildings with increased load-bearing capacity, it is advisable to give preference to thick rolled steel from low-carbon, low-alloy steels, since it, with the same level of strength as construction steels, has a higher level of plasticity. At the same time, the problem of using thick rolled steel from low-carbon, low-alloy steels in the construction industry are the anisotropy of the rolled metal properties, which can increase with an increase in the thickness of the rolled metal. Currently, in Ukraine, controlled rolling is one of the most promising technologies of high-temperature thermomechanical processing for the production of thick rolled metal from low-carbon, low-alloy steels. At the same time, with an increase in the thickness of the rolled metal, which is produced with this technological scheme, the effect of the regulated formation of the structural state decreases due to the influence on the temperature of the surface layers of the rolled metal, the thermodynamic state of the inner layers and the inability of the rolling equipment available at domestic enterprises to deform the metal over the entire cross-sectional area. Therefore, the task of obtaining such a structural state in the thick sheet metal roll, which will ensure the reduction of the anisotropy of the properties, which will allow the use of such rolled metal in the construction industry, is urgent. Purpose of the article is to study of the structural state of low-carbon low-alloy steel 10G2FB, which was produced using the technology of controlled rolling, depending on the thickness of the rolled metal. Conclusion. The relationship between the structural state and the thickness of rolled metal from low-carbon low-alloy steel 10G2FB, which was produced by controlled rolling technology, was studied. It was established that with the increase in thickness, the percentage content of the ferrite component increases with a simultaneous decrease in the percentage content of the pearlite phase. It is shown that changes in the formation languages of structural components begin with an increase in the thickness of the rolled metal over 30 mm, which is explained by the influence of the temperature of the inner layers on the processes of forming the structural state, namely, with an increase in the thickness of the rolled metal, the thermodynamic rate of phase transformations in the middle layers of the rolled metal samples decreases. This conclusion is confirmed by two factors: firstly, an increase in the size of pearlite colonies, and secondly, a change in the morphology of the cementite framework of pearlite colonies from zigzag (thickness 16...30 mm) to ribbon (thickness 40...100 mm).

Effect of cell sintering temperature on the performance of non-noble metal loaded cerium oxide SOEC anodes

Abstract Introducing methane oxidation reaction into the anode of the high-temperature solid oxide electrolysis cell (SOEC) can reduce the power consumption for water electrolysis. Compared to the traditional conditions of methane oxidation, the methane oxidation catalyst sintered at the SOEC anode, which is closely related to the cell sintering process. This study uses non-noble metals as active sites for methane oxidation, zirconia, and samarium oxides doped ceria as catalyst support and oxygen ion conductors. The effects of anode sintering temperature on the electrochemical performance of SOEC assisted by methane oxidation were investigated. The results indicate that the high-temperature sintering process promotes the performance of the SOEC anode with Ni as the active site, while high temperature harms the performance of the Co-loaded anode. The sintering temperature exhibits a poor effect on the Fe-loaded anode. The Ni exhibits good enhancement of methane oxidation on reducing the electrolysis voltage of SOEC, while Co only exhibits methane oxidation assistance at low-temperature sintering. Differently, Fe has almost no obvious methane oxidation assistance for SOEC, which mainly represents good oxygen evolution performance.