Phase Composition Research Articles

FEATURES OF THE FORMATION OF THE PHASE COMPOSITION AND PROPERTIES OF HIGH ALLOY STEEL 03Х17Н3Г9МБДЮЧ

Purpose. Evaluation of the influence of alloying elements of corrosion-resistant steel 03Х17Н3Г9МБДЮч on the phase composition and indicators of high-temperature corrosion. Research methods. In order to check the effect of the chemical composition on the structure of steel 03Х17Н3Г9МБДЮч, laboratory steels were made. The production of these steels was carried out in an induction furnace with a main lining with a capacity of 50 kg. The resulting castings were forged into blanks 40 ´ 80 ´100 mm in size, with subsequent hot rolling into samples 25, 20, and 15 mm thick. Determination of the yield strength of steels was carried out after exposure at a temperature of 850 °С for 10,000 hours. The corrosion resistance of the test samples was determined by the gravimetric method after the samples were completely immersed in molten magnesium. Results. The choice of the main alloying elements was justified and their influence on durability in the aggressive environment of the recovery process of spongy titanium production was determined. A thermodynamic calculation of the changed Gibbs energy in the operating temperature range was performed. The required phase ratio of 03Х17Н3Г9МБДЮч steel was considered and selected based on Scheffler de Long and Potak-Sahalevich diagrams. Scientific novelty. The effect of changing the chemical composition of steel 03Х17Н3Г9МБДЮч within technical conditions on the creep limit and durability in the aggressive environment of the recovery process of the production of spongy titanium was determined. Practical value. It is shown that the alloying complex of corrosion-resistant steel is capable of significantly improving the physical, mechanical and technological properties, and expanding the functional application (purpose).

Recycling of environmental harmful industrial wastes in eco-friendly building materials production suitable for specific applications

Sustainable building materials are one of the main principles to achieve sustainable construction. It refers to the potential of utilizing environmentally harmful industrial wastes to reduce the consumption of raw materials/energy used in producing ordinary Portland cement (OPC). Ground-granulated blast-furnace slag (GGBFS), lead-bearing sludge (LBS), metakaolin (MK) and fly ash (FA) were used in this work to develop eco-green binding materials with several advanced applications. Five specimens were prepared, including a control specimen (100 % GGBFS, S0) and four ternary-blended geopolymers (TBGs; GGBFS/LBS/FA and GGBFS/LBS/MK) with different proportions. The experimental work examined the mix-design's influence of the TBGs on the fresh/hardened characteristics and resistance against elevated-temperature (200–900 °C), high-dose gamma-radiation (1000–3000 kG y) and mico-organisms (Salmonella-typhi, Bacillus-Cereus, Aspergillus-oryzae and Aspergillus-fumigatus). Also, the XRD, TGA/DTG (phase composition analysis) and SEM/EDX (microstructure analysis) were studied. The findings revealed that LBS significantly reduces workability compared to MK and FA. Although the LBS, MK, and FA mixture elongated the setting time, its values are still within acceptable limits. The strength values obtained by TBGs after 28 days ranged from 51.0 to 66.7 MPa, revealing that these wastes are good alternatives to OPC. TBGs proved effective in resisting elevated-temperatures and high-dose gamma-radiation compared to S0 by forming highly-stable zeolitic compounds. The S0 specimen cannot hinder Salmonella typhi's growth; unlike TBGs, the existence of PbO2, Fe2O3, and TiO2 in the matrix inhibits all microorganisms' growth.

Fabrication, Microstructural Evolution, and Mechanical Properties of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C Nanocomposites

A dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C high-entropy ceramic nanocomposite was prepared using a polymer-derived ceramic (PDC) method combined with spark plasma sintering (SPS). The microstructural evolution and mechanical properties of the obtained nanocomposites were characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning-electron microscope (SEM), and nanoindentation. The results indicate that the phase composition of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C can be adjusted by modifying the metal content of the single-source precursor (SSP) through molecular design. The resulting precursor exhibits an exceptionally high ceramic yield, with mass retention of over 90% at 1100 °C, which guarantees the densification of the final SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C composites. The PDC route facilitates the in situ formation of a high-entropy phase within the ceramic matrix under low temperature pyrolysis conditions. Combined with SPS, a dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C nanocomposite was obtained, exhibiting an open porosity of 0.41 vol%, nano-hardness of 27.47 ± 0.46 GPa, elastic modulus of 324.00 ± 13.60 GPa, and fracture toughness of 3.59 ± 0.24 MPa·m0.5, demonstrating excellent mechanical properties.

Influence of Strain Rate on Barkhausen Noise in Trip Steel

This paper deals with Barkhausen noise in Trip steel RAK 40/70+Z1000MBO subjected to uniaxial plastic straining under variable strain rates. Barkhausen noise is investigated especially with respect to microstructure alterations expressed in terms of phase composition and dislocation density. The effects of sample heating and the corresponding Taylor–Quinney coefficient are considered as well. Barkhausen noise of the tensile test is measured in situ as well as after unloading of the samples. In this way, the contribution of external and residual stresses on Barkhausen noise can be distinguished in the direction of tensile loading, as well as in the transversal direction. It was found that the in situ-measured Barkhausen noise grows in both directions as a result of tensile stresses and the realignment of domain walls. The post situ-measured Barkhausen noise drops down in the direction of tensile load due to the high opposition of dislocation density at the expense of the growing transversal direction due to the prevailing effect of the realignment of domain walls. The temperature of the sample remarkably grows along with the increasing strain rate which corresponds with the increasing Taylor–Quinney coefficient. However, this effect plays only a minor role, and the density of the lattice imperfection expressed especially in terms of dislocation density prevails.

Comparison of composition, properties and modifying effect in epoxy compositions of natural and synthetic diopside-containing fillers

Diopside is one of the key components in various construction materials and can also be used as a filler for epoxy compositions. However, due to the complexity and labor intensity of developing domestic deposits of this calcium magnesium silicate, it is rational to synthesize diopside based on rice husk ash and dolomite and compare its phase composition and properties with diopside concentrate mined in nature.It has been established that the synthesized calcium-magnesium silicate, compared to the natural mineral, contains 10 times more diopside, has a 3 times smaller pore volume and an almost 5 times smaller average particle size, i.e. they differ significantly in both phase and granulometric composition, as well as in porosity.At the same time, both natural and synthetic diopside-containing fillers increase the hardness, wear resistance and viability of epoxy compositions. A filler synthesized on the basis of rice husk ash is more effective in terms of increasing the performance characteristics of epoxy materials.

Synthesis and Characterization of Zirconia-Based Ceramics: A Comprehensive Exploration of Film Formation and Mixed Metal Oxide Nanoparticle Synthesis

Due to its strong ionic conductivity and superior mechanical qualities, zirconia-based ceramics are frequently used in electrochemical devices. Today, zirconium oxychloride octahydrate and ethanol have been developed for the purpose of reducing zirconium thin films on glass, single-crystal silicon p-type, substrates. The phase composition and properties of the films, as well as the physicochemical processes involved in film formation, have all been investigated. Zirconia mixed metal oxide nanoparticles with various physicochemical properties can be created using a variety of synthetic processes in conjunction with additional variables like concentration, PH, type of precursor utilized, etc. In order to create zirconia mixed metal oxide nanoparticles, many synthetic techniques, including sol-gel, hydrothermal, and coprecipitation methods are discussed in this article.

Dynamic Behavior of Pt Multimetallic Alloys for Active and Stable Propane Dehydrogenation Catalysts.

Improving the use of platinum in propane dehydrogenation catalysts is a crucial aspect to increasing the efficiency and sustainability of propylene production. A known and practiced strategy involves incorporating more abundant metals in supported platinum catalysts, increasing its activity and stability while decreasing the overall loading. Here, using colloidal techniques to control the size and composition of the active phase, we show that Pt/Cu alloy nanoparticles supported on alumina (Pt/Cu/Al2O3) displayed elevated rates for propane dehydrogenation at low temperature compared to a monometallic Pt/Al2O3 catalyst. We demonstrate that the enhanced catalytic activity is correlated with a higher surface Cu content and formation of a Pt-rich core and Cu-rich shell that isolates Pt sites and increases their intrinsic activity. However, rates declined on stream because of dynamic metal diffusion processes that led to a more uniform alloy structure. This transformation was only partially inhibited by adding excess hydrogen to the feed stream. Instead, cobalt was introduced to provide trimetallic Pt/Cu/Co catalysts with stabilized surface structure and stable activity and higher rates than the original Pt/Cu system. The structure-activity relationship insights in this work offer improved knowledge of propane dehydrogenation catalyst development featuring reduced Pt loadings and notable thermal stability for propylene production.

Effect of Annealing Conditions on Resistive Switching in Hafnium Oxide-based MIM Devices for Low-power RRAM

Abstract This work presents resistive switching (RS) behaviour in HfO2-based low-power resistive random-access memory (RRAM) devices. A metal-insulator-metal (MIM) structure (Au/HfO2/Pt) was fabricated by sandwiching a thin insulating layer of HfO2 between Pt and Au electrodes. HfO2 films deposited by RF sputtering at room temperature were rapid thermally annealed in N2 ambient at 400 °C and 500 °C. Grazing angle X-ray diffraction (GIXRD), Field emission gun-scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were employed to analyse the phase, crystal structure, morphology, surface roughness and chemical composition of the HfO2 films. The bipolar RS could be observed in both as-deposited and annealed HfO2 film-based devices from I-V characteristics measured using a source meter. We have investigated the effect of annealing temperature and annealing ambient on the phase formation of HfO2 as well as the RS characteristics and compared with as-deposited film-based device. Annealed HfO2 film-based devices exhibited improved electrical characteristics, including stable and repeatable RS at significantly lower switching voltages (˂1 V) which indicates low power consumption in these devices. The relatively lower processing temperature of the HfO2 films and that too in the films deposited by physical vapor deposition (PVD) technique-RF magnetron sputtering makes this study significantly useful for resistive switching based non-volatile memories.

Selective Reduction of Iron in High-Phosphorus Oolitic Ore from the Lisakovsk Deposit

Reduction of iron in high-phosphorus oolitic ore from the Lisakovsk deposit using solid carbon, carbon monoxide, and hydrogen. An X-ray phase analysis was used to determine the phase composition of the samples after reduction roasting. When reduced with carbon monoxide or hydrogen, α-iron appears in the samples, while phosphorus remains in the form of iron, calcium, and aluminum phosphates. After roasting with solid carbon, phosphorus is reduced from iron and calcium phosphates and migrates into the metal but remains in aluminum phosphate. A micro X-ray spectral analysis showed that at a temperature of 1000 °C and a holding time of 5 h, during reduction with solid carbon, the phosphorus content in the metallic phase reaches up to 7.1 at. %. When reduced with carbon monoxide under the same conditions, the metallic phase contains only iron, and phosphorus is found only in the oxide phase. When reduced with hydrogen at 800 °C, phosphorus is almost absent in the metallic phase, but at 900 °C, phosphorus is reduced and its content in the metallic phase reaches 2.1 at. %.

Formation of structural-phase state of Ti–Al materials with Hf-additives obtained by hydride technology

The paper describes the structural and phase composition of TiHf50, AlHf50, TiAl49Hf2 composite materials obtained by the “hydride” technology. A three-component phase diagram for Ti-Al-Hf at 1150°C is constructed. The structural state of TiAl49Hf2 alloys was predicted based on reference lattices found in the USPEX code with the VASP interface; quantum-chemical calculations of the TiAl49Hf2 energy were additionally performed in the CASTEP code. It is shown that solid solutions dominate in the TiAl49Hf2 alloy sample, in which the main elements dominate: Al10 – Ti9Al23 – Ti8. Hf atoms can be introduced into the interstitial sites [-0.257 0.042 0.2545] (St-Hf-27), [0.0053 -0.0120 -0.0765] (St-Hf-143), [0.5 0.5 0.5] (St-Hf). The introduction of hafnium into the specified lattice sites does not violate the stabilizing effect in the TiAl49Hf2 systems. It is shown that the maximum microhardness value (4.9 GPa) was obtained when testing the TiHf50 sample (for comparison: for the TiAl50 system – 1.2 GPa, for the TiAl49Hf2 system – 2.2 GPa).

Formation of structural-phase state of Ti–Al materials with Zr-additives obtained by hydride technology

The structural and phase composition of TiZr50, AlZr50, TiAl49Zr2 composite materials obtained by the hydride technology was investigated. A model three-component phase diagram was constructed for Ti–Al–Zr at a temperature of 1150°C. The structural state of TiAl49Zr2 alloys was predicted based on reference lattices (USPEX code with VASP interface), quantum-chemical calculations of the energy of TiAl49Zr2 were carried out in the CASTEP code. Solid solutions dominate in TiAl49Zr2, in the composition of which the main elements are predominant: Al10–Ti9Al23–Ti8. Zr atoms can be introduced into the interstitial sites [– 0.257 0.042 0.2545] (St–Zr–27), [0.0053–0.0120–0.0765] (St–Zr–143), [–0.3251–0.3983 0.4880] (St–Zr– 75). The introduction of Zr into the specified lattice sites does not violate the stabilizing effect in the TiAl49Zr2 systems. All reference lattices are stable. In the TiAl49Zr2 alloy, the main phases are Al10Ti9Zr, Al23Ti8Zr, the contributions of which to the theoretical intensity are 78.57 and 21.43%. In the AlZr50 sample, the phases ZrAl, Zr2Al3, ZrAl2.

Development and Validation of an optimized HPLC-UV analytical method for the quantification of 5-Methyltetrahydrofolate (Active Folate) in dietary Supplements: Application to commercial tablets and capsules

5-MTHF is the active form of folic acid, and it is provided as a dietary supplement in the market. Therefore, in this study we provide a new, simple and economic HPLC-UV analysis method to quantify 5-MTHF in dietary supplement. A new HPLC-UV method was developed and validated for the quantification of 5-methyltetrahydrofolate in dietary supplements. The method was optimized in terms of chromatographic conditions, including the mobile phase composition, chromatographic column, and the sample preparation diluent using ascorbic acid. A combination of ammonium acetate buffer with methanol (90:10) was the optimal mobile phase, achieving a retention time of approximately 11.4 min on C18 column with good column performance (N = 6786, Asymmetry = 1.03). The method was validated for selectivity, linearity, precision, accuracy, and robustness. The calibration curve was linear (r2 > 0.999) over the concentration range of 1.20 to 4.80 µg/mL. Precision was demonstrated with RSD% values ranging from 1.38 % to 2.90 % for intra-day precision and 0.96 % to 2.61 % for inter-day precision. Accuracy was confirmed with recovery values between 96.5 % and 110.6 % for spiked samples. To demonstrate the method’s applicability, ten brands of 5-MTHF dietary supplements were collected from local pharmacies. Assay results showed significant variability, with four brands having contents below the acceptable range (90–110 % of labeled contents) and two brands exceeding this range. The stability of 5-MTHF in these products appeared to be formula-dependent, emphasizing the need for regulatory revisions to mandate stability testing for dietary supplements.

Thermal management of lithium-ion batteries based on the coupling of liquid cooling and composite phase change materials

ABSTRACT Effective thermal management techniques for lithium-ion batteries are crucial to ensure their optimal efficiency. This paper proposes a thermal management system that combines liquid cooling with composite phase change materials (PCM) to enhance the cooling performance of these lithium-ion batteries. A numerical study was conducted to examine the impact of various factors on the battery module’s thermal management performance, including the number of flow channels, the distance between these flow channels and the upper and front surfaces, fluid flow rate, coolant inlet temperature, and material’s phase change temperature. The simulation results indicate that at a discharge rate of 6C and a flow channel count of 5, the maximum temperature and the maximum temperature difference of the battery module decrease by 6.44% and 34.35%, respectively, when PCM is coupled with liquid cooling, compared to the pure liquid cooling. However, as the flow rate increases, the rate of temperature reduction slows down, while the pressure drop increases. When the flow rate reaches 0.4 m/s, the maximum temperature only drops by 0.57°C while the pressure drop increases by nearly two times. Furthermore, an increase in the PCM’s melting temperature leads to a larger maximum temperature difference in the battery module. This effect is more pronounced with higher coolant inlet temperatures. Therefore, careful consideration of both flow rate and coolant inlet temperature is essential for designing an effective thermal management system for batteries.

Role of t-ZrO2 stabilization methods in phase composition, structure and properties of ZTA ceramics

Role of t-ZrO2 stabilization methods in phase composition, structure and properties of ZTA ceramics

Reactive Spark Plasma Sintering and Oxidation of ZrB2-SiC and ZrB2-HfB2-SiC Ceramic Materials

This study presents the fabrication possibilities of ultra-high-temperature ceramics of ZrB2-30 vol.%SiC and (ZrB2-HfB2)-30 vol.% SiC composition using the reaction spark plasma sintering of composite powders ZrB2(HfB2)-(SiO2-C) under two-stage heating conditions. The phase composition and microstructure of the obtained ceramic materials have been subjected to detailed analysis, their electrical conductivity has been evaluated using the four-contact method, and the electron work function has been determined using Kelvin probe force microscopy. The thermal analysis in the air, as well as the calcination of the samples at temperatures of 800, 1000, and 1200 °C in the air, demonstrated a comparable behavior of the materials in general. However, based on the XRD data and mapping of the distribution of elements on the oxidized surface (EDX), a slightly higher oxidation resistance of the ceramics (ZrB2-HfB2)-30 vol.% SiC was observed. The I-V curves of the sample surfaces recorded with atomic force microscopy demonstrated that following oxidation in the air at 1200 °C, the surfaces of the materials exhibited a marked reduction in current conductivity due to the formation of a dielectric layer. However, data obtained from Kelvin probe force microscopy indicated that (ZrB2-HfB2)-30 vol.% SiC ceramics also demonstrated enhanced resistance to oxidation.

Fabrication and Characterization of Advanced Selective Plated Copper Coatings Incorporating Nanosized Particles of ZnO and TiO2

This study reports preliminary results on the fabrication and characterization of selective plated copper-based coatings with enhanced surface properties and durability through the incorporation of zinc oxide and titanium oxide particles. The coatings were produced using an electrolyte containing 3% wt. zinc oxide and 1% wt. titanium oxide particles, and their microstructures, phase compositions, and mechanical properties were investigated. The results show that the incorporation of ceramic particles leads to the formation of metal-matrix composite materials with finer grain structures, improved microhardness, and enhanced wear resistance. The coating incorporating ZnO particles exhibits superior wear resistance, maintaining stable roughness values and minimal material loss, while the coating with TiO2 particles also shows improved wear resistance with moderate roughness increases.

Precipitation strengthening behavior of Custom 455 stainless steel during tempering at 420 °C

After solid solution at 850 °C, the Custom 455 was aged at 420 °C for different times. The hardness changes were measured using a Vickers hardness tester, and the microstructure and composition of the second phase were studied using atom probe tomography (APT) and high-resolution transmission electron microscopy (HRTEM). The APT results indicate that in the early stage of aging, Cu atoms first segregate and attract Ti to form CuTi clusters; As the aging time increases, Ti atoms in CuTi clusters attract Ni and form CuTiNi clusters, resulting in a rapid increase in sample hardness; Subsequently, CuNiTi clusters grew and gradually separated into Cu-rich and NiTi-rich particles; As the aging time further increases, some NiTi-rich particles grow into rod-shaped Ni3Ti precipitates, while others have Si atoms and grow into spherical G phase particles. The orientation relationship between Cu-rich phase, Ni3Ti phase, and G phase is: [100]M//[0–11]Cu//[-12–10]Ni3Ti//[100]G, (011)M//(111)Cu//(0004)Ni3Ti//(022)G. The formation of the Cu-rich, Ni3Ti, and G phase resulted in a hardness peak of 538 HV after 16 h of aging. Subsequently, the decrease in hardness caused by the coarsening of the Cu-rich and Ni3Ti particles was offset by the newly formed G phase, resulting in a slow decrease in hardness.

Versatility of the Templated Surface Assembly of Nanoparticles from Water-in-Oil Microemulsions in Equivalent Hybrid Nanostructured Films

Water-in-oil microemulsions, as stable colloidal dispersions from quasi-ternary mixtures, have been used in diverse applications, including nanoreactors for confined chemical processes. Their use as soft templates not only includes nanomaterial synthesis but also the interfacial assembly of nanoparticles in hybrid nanostructures. Especially the hierarchical arrangement of different types of nanoparticles over a surface in filament networks constitutes an interesting bottom-up strategy for facile and tunable film coating. Herein, we demonstrate the versatility of this surface assembly from microemulsion dispersions. Transmission and Scanning Electron Microscopy, in addition to UV–Vis Transmittance Spectroscopy, proved the assembly tunability after solvent evaporation under different conditions: the nanostructured films can be formed over different surfaces, using different compositions of liquid phases, as well as with the incorporation of different nanoparticle materials while keeping equivalent surface functionalization. This offers the possibility of adapting different components and conditions for coating tuning on a larger scale with simple procedures.

Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells

Two second-phases with an opposite potential difference to the α-Mg matrix may affect the discharge mechanism of magnesium (Mg) anodes for primary Mg-air cells through different micro-galvanic behaviors. Herein, using Mg–Ca-xSn alloys anode with Mg2Ca and CaMgSn phases, we investigated their influence on the dissolution mode of Mg-anode during discharge state via in-situ scanning vibrating electrode technique (SVET) technology. Firstly, the peak surface positive potential of Mg–1Ca alloy only containing Mg2Ca phase and Mg–1Ca–1Sn alloy with CaMgSn/Mg2Ca phase increases multiplied by 10 during the discharge process compared to that of OCP, exhibiting accelerated anodic substrate dissolution. Moreover, Mg2Ca-phases can be attacked firstly while promoting the discharge of the α-Mg matrix surrounding them, leading to the preferential dissolution of grain boundaries and “chunk effects (CE)” occurrence. More CaMgSn/α-Mg couples are activated to form dispersed micro-galvanic cell islands, which also boosts the dissolution of the α-Mg matrix but reduces the area of high-intensity dissolution reaction due to CaMgSn acting as a cathode. However, excessive CaMgSn-phase generally fails to discharge effectively to reduce anode efficiency, although it can improve the self-peeling capacity of the film layer through physical detachment; in addition, with Sn content increasing to 3 wt%, the open circuit voltage of Mg–1Ca–3Sn significantly declines. Mg–1Ca-0.2Sn exhibits the highest cell voltage and anodic efficiency by introducing a tiny amount of dispersed short rod-like CaMgSn, due to the adjusted dissolution mode, enhanced electrochemical activity and inhibited CE. Finally, our study provides a universal mechanism for fabricating Mg-anode with high performance via phase composition modulation.

Study of structural and mechanical properties of composite ceramics of the AlMgB14–TiB2 system

AlMgB14 ceramics is known as a material characterized by increased hardness in combination with a low friction coefficient. Composite structures based on this ceramics have even higher strength characteristics. In the present work, we investigate the structural-phase states and physicomechanical properties of composite ceramics of the AlMgB14–TiB2 system with a variable TiB2 content, obtained by hot pressing the initial batch based on AlMgB14 and TiB2 ceramic powders preliminarily synthesized by the method of self-propagating high-temperature synthesis. It was found that the resulting materials are characterized by a composite structure represented by TiB2 inclusions distributed in the AlMgB14 matrix. The phase composition of the resulting composites is similar to the phase composition of the initial batch, with 5 to 9 wt. % of the MgAl2O4 spinel phase being formed. The microhardness of AlMgB14–TiB2 composites is up to 19.9 GPa (the hardness of AlMgB14 ceramics obtained by a similar method without additives is 7 GPa). The three-point bending strength of AlMgB14–TiB2 composite materials is 309 MPa.