Differential Scanning Calorimetry Methods Research Articles

The effect of silicon dioxide on the structural, thermal and transport properties of an organic ionic plastic crystal (n-C4H9)4NBF4

Composite solid electrolytes based on an organic ionic plastic crystal (n-C4H9)4NBF4 with highly dispersed SiO2 with specific surface area of Ss = 324±10 m2/g have been studied for the first time. By methods of X-ray diffraction and differential scanning calorimetry, it was found that the introduction of SiO2 leads to amorphization of the salt. An unusual size effect was observed in the composites: the temperature of the polymorphic transition of the salt shifted from 67 °C to 60 °C, while the melting point did not change. The 0.15(n-C4H9)4NBF4–0.85SiO2 composite was found to possess the highest electrical conductivity (σ = 2∙10–5 S/cm at 150 °C), which is 1.5 orders of magnitude higher than that of the initial salt. Modelling of the concentration dependences of the electrical conductivity of composites using the mixing equation showed that the reason for the increase in electrical conductivity is the formation of an amorphous layer of salt, the electrical conductivity of which is 3 orders of magnitude higher than that of the crystalline phase (n-C4H9)4NBF4. The obtained results can be used for the design of high-performance composites based on organic ionic plastic crystals for application in electrochemical devices.

Enhancement of aluminum powder reaction behavior at high temperatures—Aluminum powders with “sea urchin structure” coated by AP

To solve the problem of high ignition temperature of aluminum powder and easy to burn into blocks at high temperatures, “sea-urchin-structured” aluminum powders (μAl@nAl) obtained by electro-explosion were coated by ammonium perchlorate (AP) on its surface. AP in a high-temperature environment has a rapid decomposition, then the gas production will promote the dispersion of aluminum powder into micro-clusters, thus preventing the aluminum powder agglomeration during the combustion process. The micro-nano composite aluminum powder (μAl@8 %nAl) and physical mixed aluminum powder (μAl + 8 %nAl) coated by AP were completed by solvent volatilization method. The coating surface was observed by scanning electron microscopy. The heat of combustion and pressure curves for different AP contents were tested using a chamber with a constant volume, and the ignition and combustion performance of the AP samples were investigated using a carbon dioxide (CO2) laser ignition device. The AP samples shortened the ignition delay time and improved the combustion performance in the fixed-volume combustion and laser ignition tests. Under atmospheric air, taking into account the theoretical calorific value, pressure curve, and combustion performance, the optimal AP content is 10 %. The thermal decomposition process of two samples was further analyzed using the thermogravimetric and differential scanning calorimetry (TG-DSC) method. The decomposition of AP advanced the first oxidation peak of aluminum powder; however, in the second step oxidation peak, the peak temperature of μAl@8 %nAl@10 %AP sample was delayed compared to μAl + 8 %nAl@10 %AP sample. High-voltage electrical explosions and high-energy laser-induced air shock waves were created to simulate the high-temperature environment of the detonation reaction zone, and pictures of the reaction process and pressure change curves of the “sea urchin structure” aluminum powder coated by AP at high temperatures were recorded. The results showed that the “sea urchin structure” aluminum powder coated by AP exhibited better combustion performance, and the reaction degree of the aluminum powder had been deepened.

Synthesis and Structure of Barium Hexaferrite BaFe12–xInxO19 (x = 0–1)

This study presents the results of the synthesis and examination of indium-substituted barium hexaferrite samples with the formula BaFe12–xInxO19. The ferrites were obtained via a solid state synthesis method. The substitution level of indium, represented by x(In), was varied from 0 to 1 in 0.25 increments. The stoichiometric formulas of the compounds were calculated using the EDS data. The powder X-ray diffraction analysis indicated that all samples form a single crystalline phase with the M-type hexaferrite structure. Parameters of the crystal unit cell were calculated from powder diffraction data. An expansion of the crystal lattice parameters was observed as iron was substituted with indium, from x = 0 to x = 0.84. The Curie temperatures of the synthesized ferrites were determined using differential scanning calorimetry (DSC) method. It is established that the Curie temperature decreases from 452 to 292°C with In content growth from x = 0 to x = 0.84 in the BaFe12–xInxO19.

GLC, DSC, and IR spectroscopy methods in the study of bovine milk fat

In order to achieve reliable identification of natural bovine milk fat, we obtained gas chromatography data using a flame ionization detector (GLC-FID) on the fatty acid composition of milk of 4 breeds: Red Pied, Black Pied, Holstein, and Jersey. The milk was obtained during the transition period from pasture to indoor housing using the method recommended by GOST 32261-2013. Gas chromatographic data (GLC-FID) on the triglyceride composition were obtained according to GOST R 70238-2022. In addition to chromatographic techniques, we also studied thermograms of milk fat by differential scanning calorimetry (DSC) and analysed the IR spectra of milk fat samples. The statistical analysis of data on the total influence of genetic and phenotypic factors on the chemical composition of fats and oils, on thermophysical parameters (temperatures and thermal effects of melting, polymorphic transformations) revealed close natural correlations between some individual fatty acids, triglycerides, and DSC thermophysical parameters characteristic of certain lipids. Violation of the revealed correlations may indicate the use of fat substitutes in the product, fractionation, transesterification, or other physicochemical impacts on fat and oil raw materials. Using a set of GLC-FID, DSC, and IR spectroscopy techniques makes it possible not only to reliably identify natural raw materials, but often their origin as well, i.e. the breed of livestock and the production conditions of agricultural products.

Analysis of the effect of boric acid and compatibilizer addition to polylactic acid/basalt fiber composites

AbstractThe objective of this study is to improve the properties of polylactic acid (PLA), a biopolymer produced from renewable resources, without compromising its environmentally friendly “natural composite” properties. The aim was to expand the application range of PLA by making it suitable for the production of high performance composites. With this in mind, it was decided to use inorganic and environmentally friendly materials such as basalt fiber (BF) and boric acid (BA) as reinforcements. Adhesive wear and tensile tests were used to investigate the tribological and mechanical performance of the composites. Differential scanning calorimetry (DSC) and dimensional stability analysis (DSA) methods were used to investigate the thermal properties. Scanning electron microscopy analysis was also used to investigate the morphological properties of the samples. In addition, a matrix modification process using Joncryl®, an epoxy‐based chain extender chemical, was applied to enhance the interfacial interaction between the composite components and improve the composite properties by improving the dispersion of reinforcing materials. As a result of the characterization tests, it was observed that a significant improvement in the properties of the material type containing 10 wt% BF, 0.25 wt% BA and 2 wt% Joncryl® was achieved. A 19% increase in tensile strength of this type of material was observed compared with unreinforced PLA, while the sharp peak increase in the coefficient of friction (COF) curve was shifted from 20 m to 60 m. As a result, it has been presented that environmentally friendly and inorganic materials such as BF and BA can be used to produce composite materials that will serve sectors where the need and use of high performance materials is intense, especially in the automotive, aerospace and aviation sectors.Highlights The properties of PLA matrix composites were improved by the simultaneous use of BF and BA and the addition of Joncryl®. The structural properties of PLA, an environmentally friendly polymer, have been improved without compromising this characteristic. PLA matrix natural composites with performance that can be used in the automotive, aerospace and aviation sectors have been developed.

Analysis of cryopreservation media thermophysical characteristics after ultra-rapid cooling through differential scanning calorimetry

Cryoprotective agents play a critical role in minimizing cell damage caused by ice formation during cryopreservation. However, high concentrations of CPAs are toxic to cells and tissues. Required concentrations of CPAs can be reduced by utilizing higher cooling and warming rates, but insight into the thermophysical properties of biological solutions in the vitrification method is necessary for the development of cryopreservation protocols. Most studies on thermophysical properties under ultra-rapid cooling conditions have been qualitatively based on visualization. Differential scanning calorimetry methods are ideal for studying the behavior of biomaterials in various freezing conditions quantitatively and accurately, though previous studies have been predominantly restricted to slower cooling rates. Here, we developed an ultra-rapid cooling method for DSC that can achieve minimal cooling rates exceeding 2000 °C/min. We investigated the thermophysical vitrification behavior of ternary solutions of phosphate buffer saline (1X), dimethyl sulfoxide or glycerol and ice blocking polymers (X-1000 or Z-1000). We quantified the impact of solute concentration on ice crystal formation during rapid cooling. Our findings support the expectation that increasing the solute concentration reduces the amount of ice formation, including devitrification. Devitrification increases from 0 % to 40 % (v/v) Me2SO and then reduces significantly. The relative amounts of devitrification to the total ice formation are 0 %, 60 %, 0 % in 20 %, 40 %, 60 % (v/v) Me2SO, and 2 %, 48 %, 49 % in 20 %, 40 %, 60 % (v/v) glycerol, respectively. The results suggest that at low concentrations, such as below 20 % (v/v) for Me2SO or glycerol, increasing the warming rate after ultra-rapid freezing is not essential to eliminate devitrification. Furthermore, ice blocking polymers do not reduce ice formation substantially and cannot eliminate devitrification under ultra-rapid cooling conditions. In conclusion, our results provide insights into the impact of solute concentration on ice formation and devitrification during rapid cooling, which can be practical for optimizing cryopreservation protocols.

Static layer melt crystallization of dimethyl carbonate: Binary thermodynamic phase diagram analysis and process optimization

Dimethyl carbonate (DMC) is one kind of important solvent for lithium battery electrolyte. The purifying method of DMC is crucial for obtaining high purity product of it. Using a green and sustainable technology makes more sense in the face of increasing environmental burdens. In this study, a static layer melt crystallization method was used to achieve the purification of high purity DMC from a mixture of DMC and its major impurities. The partial binary phase diagrams between DMC and the main impurity - methanol (MT) - were determined using differential scanning calorimetry (DSC) method. Effect of process parameters such as crystallization temperature, cooling rate, sweating temperature, and heating rate on the distribution coefficient Kf and yield Y were evaluated using One-factor-at-a-time (OFAT) experiment and response surface experiment, respectively. The phenomenological relationships between different parameters and distribution coefficient and yield were discussed and revealed. Eventually, under the optimized process conditions, the purity of DMC was increased from 96 % to 99.847 %, and the single yield could reach 70 %.

Determination the influence of the synthetic antioxidants mixture on the oxidative stability of sunflower oil

The object of the study is the process of sunflower oil oxidation under conditions of increased temperature. Sunflower oil is one of the most common oils and is used in the chemical, food and other industries. The main type of oil spoilage is oxidation, which is accelerated under the influence of radiation, elevated temperatures, long-term storage with oxygen access. Oxidation products prevent the effective use of oil in chemical reactions and technological processes. An important task is to develop and improve methods for increasing the oxidative stability of sunflower oil using antioxidants. The oxidation process of refined deodorized frozen sunflower oil according to DSTU 4492 (CAS Number 8001-21-6) was studied by the method of differential scanning calorimetry. The simultaneous effect of synthetic antioxidants (tert-butylhydroquinone, butylhydroxyanisole, butylhydroxytoluene) in different ratios on the oil induction period at a temperature of 110 °C was determined. The total concentration of the antioxidant mixture in each experiment was 0.02 %. The initial oil induction period is 270.61 min. Rational ratios of antioxidants were determined: tert-butylhydroquinone: butylhydroxyanisole: butylhydroxytoluene (16.67:66.67:16.67) %; tert-butylhydroquinone: butylhydroxyanisole: butylhydroxytoluene (33.33:33.33:33.33) %. The corresponding oil induction periods were 382.56 min. and 385.87 min. The effect of citric acid (0.005 %) and defoamer (polydimethylsiloxane, 0.0002 %)) on the induction period of oil with the addition of antioxidant mixtures was determined. The corresponding oil induction periods were 420.78 min. and 430.25 min. The results of the study make it possible to increase the oxidative stability of sunflower oil, which will contribute to the effective use of oil in various areas

Enhanced Hard Magnetic Performance for MnBi Green Powders

Mn55Bi45 melt - spun ribbons were prepared by using the melt-spinning technique followed by annealing in Ar/5%H2 gas mixture. The in-situ formation of ferromagnetic phase (denoted as LTP) of MnBi was observed by the multi-section cycled Differential Scanning Calorimetry (DSC) method. It was found that, the optimal annealing temperature range for forming MnBi LTP is 250 – 280 oC. The prolonging annealing time increases the content of MnBi LTP leading to the increase of saturation magnetization Ms but paid by the drop of the intrinsic coercivity iHc. The MnBi green powders were prepared by the Low Energy Ball Milling method (LEBM) in N2 liquid. The maximum energy product of MnBi green powders is estimated about 10.8 MGOe.

An Environmentally Friendly Solvent for Cellulose Acetate Production: Ethyl Lactate

The aim of this study was to investigate the possibilities of using biodegradable ethyl lactate instead of acetic acid, the most preferred solvent in industrial production, during cellulose acetate synthesis under certain conditions. In the study, dissolving pulp fibres, which were activated with water and acetic acid respectively, were dispersed in ethyl lactate after pressing and then subjected to acetylation reaction with acetic anhydride catalysed by sulfuric acid. The properties of acetylated cellulose were determined using X-Ray diffraction analysis, Fourier-transform infrared spectroscopy, Differential Scanning Calorimetry and other chemical analysis methods (viscosity, the percentage of bounded acid, chemical resistance). It was determined that it was possible to produce cellulose acetate with a DS value of 2.79 in ethyl lactate at 40°C using dissolving pulp. Fourier-transform infrared spectroscopy studies revealed a characteristic band broadening in the 1739 cm-1 region, indicating the presence of acetyl groups. The results of X-ray diffraction analyses also showed that the crystalline structure of cellulose was completely dispersed and band broadenings on diffractograms occurred. However, the calculation made on X-ray diffractograms also provided interesting findings in terms of crystallite sizes. It was observed that the crystallite sizes of the acetates were higher compared to the dissolving pulp. It was determined that the high crystallinity of the samples posed a problem in terms of processing properties such as dissolution. Among the solvents used, only Dimethylsulfoxide was found to have sufficient dissolving power.

Thermally induced phase separation of UHMWPE mixture with dioctyl adipate: Competition of liquid–liquid phase separation and polymer crystallization

The thermal behavior of ultra-high molecular weight polyethylene (UHMWPE) with dioctyl adipate (DOA) was investigated by the differential scanning calorimetry (DSC) method. Capillary-porous bodies were obtained via thermally induced phase separation of DOA mixtures with polyethylenes of different molecular weight at different cooling rates. Analysis of the morphology of the prepared porous bodies together with DSC data and results of cloud point estimation revealed an unexpected effect of a cooling rate on the type of phase separation occurring in the mixture during its cooling from homogeneous state. Particularly it was shown that increase in the cooling rate reduces the probability of realization of liquid – liquid phase separation in the mixture. It was argued that such behavior, different from the standard semicrystalline polymers, is a result of kinetic hindrance of liquid – liquid phase separation in mixtures containing a polymer with such a high molecular weight.

Investigation of the Degree of Monomer Conversion in Dental Composites through Various Methods: An In Vitro Study

The degree of monomer conversion (DC) values of three different dental composites were examined using three different methods: surface microhardness (ratio of bottom/top), Fourier-transform infrared (FT-IR), and differential scanning calorimetry (DSC). Two of the dental composites included in the study were nanohybrid (Dentsply Neo Spectra ST HV and Omnichroma), and one was a microhybrid-labeled newly marketed composite containing nanoparticles (Dentac Myra). Composite discs were prepared according to the methodology for all methods and analyzed (2 mm thickness × 5 mm diameter). Surface microhardness values were measured in Vickers Hardness Number (VHN), while FT-IR and DSC values were obtained in percentage (%). Significant differences were observed in both bottom/top surface microhardness values and DC values obtained from FT-IR. However, there was no statistical difference in the ratio of bottom/top microhardness values. Neo Spectra ST HV exhibited superior performance in both microhardness and monomer conversion compared to the other two composites. Newly marketed Myra showed values close to Omnichroma. It was found that the values obtained by the DSC method were parallel to those obtained by FT-IR. In conclusion, the structure of dental composites leads to different mechanical properties. Additionally, DSC measurements and FTIR spectra were found to be complementary techniques for characterizing monomer conversion values.

Plasmonic photothermal therapy based synergistic drug release application through gold nanoparticles coated and embedded PLGA nanoparticles

Drug carrier structures based on the biocompatible polymer Poly(D-lactic-co-glycolic acid) (PLGA) are considered traditional delivery systems. To increase the potential of PLGA nanoparticle (NP)-based carriers for use in near infrared radiation (NIR)-based photothermal drug release applications, two important approaches are the combined use of gold nanoparticles with PLGA NPs structures. In this study, AuNPs were prepared both decorated on PLGA NPs and embedded in PLGA NPs structures. The particles were prepared and characterized for their structural and thermal properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC) methods. Morphological features and size distributions were also determined using Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS). Thermal changes caused by plasmonic particles under 808 nm NIR laser were examined using a thermal camera for spherical gold nanoparticle (AuNP) and star-shaped gold nanoparticle (AuNS). The most suitable increase in temperature has been obtained in the AuNS structures. Epirubicin (EPI) release studies were conducted using PLGA NPs embedded with AuNS, employing NIR and an ON/OFF based approach. Basic toxicological evaluations of these particles were performed on mouse fibroblast (L929) cells to assess biocompability properties. The study also investigated the impact of prepared EPI-loaded particles and laser-controlled drug release on cytotoxicity, ROS production, and genotoxicity, in human neuroblastoma (SH-SY5Y) cells. The results indicated that the activity of EPI-loaded AuNP@PDOP@PLGA NPs increases synergistically with the ON/OFF-based approach, as shown by the calculated combination index (CI) value. The developed combination approach shows promise for further evaluation before clinical use.

Analyzing Sustainable 3D Printing Processes: Mechanical, Thermal, and Crystallographic Insights.

In this study, the objective was to optimize energy consumption in the fused deposition modeling (FDM) 3D printing process via a detailed analysis of printing parameters. By utilizing thermal analysis techniques, this research aimed to identify lower printing temperatures that could lead to reduced energy usage. Experimental analysis was conducted using a three-level L9 Taguchi orthogonal array, which involved a systematic combination of different extruder temperatures and cooling fan capacities. Furthermore, the research incorporated differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods to analyze the thermal properties and crystallinity of the 3D-printed specimens. The results indicated that temperature was a key factor affecting crystallinity, with samples printed at 190 °C and 60% fan capacity showing the highest mean values. By conducting a multi-objective desirability analysis, the optimal conditions for maximizing ultimate tensile strength (UTS), tensile modulus, and elongation at break while minimizing energy consumption for PLA 3D-printed samples were determined to be a temperature of 180 °C and a fan speed of 80%.

Effects of Adding Sorghum Procyanidins on the Structure, Molecular Interactions, and Thermal Properties of Agar-Glycerol-Gelatin Films

Films made with blends of agar and gelatin are usually unstable in aqueous environments and susceptible to temperature, so modifying these films with the addition of compatible compounds is necessary to improve their structural stability, properties, and potential uses. This work determined the effects of adding sorghum procyanidins on the structure, molecular interactions and thermal properties of agar-glycerol-gelatin films. Films were prepared by solution cast method and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and computational methods. Adding sorghum procyanidins to agar-gelatin films plasticized with glycerol produced significant modifications compared to control films. They contributed to the amorphous character and roughness of these films and the film’s microstructure, reducing weight loss and enhancing thermal stability. The predominant interactions among the film components were hydrogen bonds, van der Waals, and [Formula: see text]–[Formula: see text] interactions.

Synthesis and upconversion luminescence properties of Ho3+-Yb3+ co-doped glass ceramics containing LiGd(WO4)2

Ho3+-Yb3+ co-doped glass ceramics containing LiGd(WO4)2 were prepared by melt crystallization method. By using the methods of differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmittance, and scanning electron microscopy (SEM), the optimal heat treatment condition for the samples was identified to be 580 °C/140 min. In these conditions, the transmittance of glass ceramic is about 75 % in the 380–780 nm range. In the upconversion emission spectra, strong green emission (543 nm) and red emission (650 nm) due to 5F4/5S2, 5F5→5I8 transitions are observed at 980 nm excitation. Additionally, the optimum doping concentrations of Ho3+ and Yb3+ were 0.12 % and 0.4 %. The crystal field changes around dopant ions were analyzed using J-O theory and Eu3+ probe to explain the up-conversion luminescence enhancement of glass ceramics containing LiGd(WO4)2. The chrominance coordinates of 0.12 % Ho3+-0.4 % Yb3+ co-doped glass ceramics are located in the green light region, and the color purity is 95.6 %. In summary, Ho3+-Yb3+ co-doped transparent glass ceramics containing LiGd(WO4)2 have potential applications in infrared detection and green solid-state lasers.

Theoretical and experimental study of molecular interactions between constituents of deep eutectic solvents

In this study, we aimed to elucidate the molecular interactions in deep eutectic solvents (DESs) and acquire additional experimental evidence to increase our understanding of the molecular mechanisms responsible for the preparation of DES. We investigated three N-methylthiourea (NMTU)-based DESs with choline chloride (ChCl), allyltrimethylammonium chloride (ATMAC), and benzyltriethylammonium chloride (BTEAC) as hydrogen bond acceptors (HBA). To accomplish this, we used both experimental techniques including isopiestic, differential scanning calorimetry (DSC), and FTIR measurements as well as molecular dynamics (MD) simulations. The thermal behaviors of the prepared DESs were investigated by DSC method. In order to study the interaction and hydrogen bonding between the DESs constituents, FT-IR analysis and isopiestic measurements were carried out. Constant solvent activity lines of ternary HBA + HBD + solvent mixtures were determined by the isopiestic technique. The large positive deviation of the isosolvent activity lines from the semi-ideal behavior indicates a strong interaction between HBA and HBD, which is much stronger than HBA-HBA and HBD-HBD interactions. Classical MD simulations were performed at 298.15 K to analyze the nanoscopic properties and structure of the DESs. To investigate the interaction between the components and visualize the three-dimensional structure of the DESs, radial distribution functions (RDFs), coordination numbers (CNs), and combined (CDFs), and spatial (SDFs) distribution functions were determined by MD simulations. The obtained theoretical results confirmed the importance of hydrogen bonds in the preparation of DESs and also showed that these systems exhibit different structural arrangements. MD simulations were also used to determine the density of the DESs and the results showed good agreement with the experimental density.

Measurement of effective thermal conductivity of composite powders of 2D materials and metals for additive manufacturing

Laser Powder Bed Fusion (LPBF), a promising additive manufacturing technique for composites of 2D materials and metals, requires knowledge of thermophysical properties, such as the thermal conductivity of powder, for process optimization. In this study, we measured the effective thermal conductivity of the most representative Cu-graphene composite powder in the field of heat transfer applications. To measure thermal conductivity, we propose a differential scanning calorimetry (DSC) method to measure the thermal resistances of a powder bed under steady-state heat flow conditions. We observe that the thermal conductivity of a composite powder is 1,000 times lower than that of the bulk metal without 2D material addition; e.g., exhibiting ~ 0.30 W/mK in Cu-1wt.% graphene powder. Furthermore, we discuss powder size and morphology impact on thermal conductivity influencing the number of contact points and thermal contact resistance. Our findings contribute to understanding the thermal conductivity of composite powders in a powder bed and aid in optimizing LPBF processes.

Green synthesis and characterization of binary, ternary, and quaternary Ti/MMO anodes for chlorine and oxygen evolution reactions

Dimensionally stable anodes of titanium (Ti) metal coated with mixed metal oxides (MMO) are widely used in several electrochemical applications, especially chloro-alkali electrolysis. Herein, we deposited MMO coatings on Ti substrates in different compositions, namely, (60%RuO2-40%TiO2), (60%RuO2-30%TiO2-10%IrO2), and (60%RuO2-20%TiO2-15%IrO2-5%Ta2O5), where RuO2 has the same percentage ratio in all coatings. The aim was to use these electrodes for chlorine evolution reaction (CER) and oxygen evolution reaction (OER) applications. Electrochemical characterization of the coated samples was performed to identify the best Ti/MMO electrodes with the highest efficiencies among the various prepared combinations. The role of IrO2 and Ta2O5 in enhancing corrosion resistance and electrochemical efficacy was up for debate. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses were exploited to determine the surface morphology, chemical composition, crystallinity, surface composition, and chemical states of the acquired coatings. The differential scanning calorimetry (DSC) method was used to evaluate the apparent activation energy (Ea\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{E}}}_{{\ ext{a}}}$$\\end{document}) of the deposited MMO. Additionally, the electrochemical performance of our designed coatings was scrutinized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), a current on–off test, a CV stability test (ST), and an accelerated stability test (AST). Furthermore, linear sweep voltammetry (LSV) was incorporated to assess the catalytic efficacy of the prepared anodes toward the CER in a brine solution of pH 2 and the OER in 1 M H2SO4. It became clear that the CER and OER incurred almost the same potential value (1.1 V) on both Ti/RuO2-TiO2 and Ti/RuO2-TiO2-IrO2 electrodes. However, on the Ti/RuO2-TiO2-IrO2-Ta2O5 anode, there was a 0.2 V potential difference between the CER occurring at 1.1 V and the OER happening at 1.3 V.

Evaluation of structural characteristics BaFe(12-x)InxO19 hexaferrite compounds at high temperatures

BaFeO-based hexaferrite compounds were synthesized by partially replacing Fe atoms with In atoms in barium hexaferrite, and their structural characteristics, thermal, and magnetic properties were studied. The crystal structure and lattice parameters of the hexaferrite were investigated using the X-ray diffraction method. Thermal property investigations were conducted at high temperatures. The results obtained by the Differential Scanning Calorimetry (DSC) method were analyzed, and the mechanisms of formation and decomposition of hydroxide groups in these crystals were explained. These effects were also determined by Thermogravimetric Analysis (TGA) studies. The vibrational magnetometry method studied the magnetic properties of BaFe11.4In0.6O19 and BaFe10.8In1.2O19 compounds. As the concentration of In atoms in the samples increases, the temperature of the ferrimagnetic-paramagnetic phase transition decreases. The observed effect in the temperature range of RT to 800 °C is attributed to weight loss due to the decomposition of structural water molecules through an endothermic reaction in hexaferrite compounds. The value of the Curie temperature for the BaFe11.4In0.6O19 compound was 383 °C, and for the BaFe10.8 In1.2O19 compound, it was 323 °C. Increasing In concentration from x = 0.6 to x = 1.2 increases the In3+ ionic radius in the structure, and due to the replacement of Fe3+ ions with more In3+ ions at x = 1.2, the magnetic hyperfine field area decreases.