Magnesium oxide (MgO) nanopowders were synthesized by an ultrasonic-assisted solution combustion synthesis route using magnesium nitrate as oxidizer and sucrose as fuel. The influence of ultrasonic pretreatment and fuel-to-oxidizer ratio on the phase composition, microstructure, surface area, particle size distribution, and dispersibility of the resulting MgO powders was systematically investigated. X-ray diffraction analysis confirmed the formation of single-phase cubic MgO for all samples. Compared to conventional solution combustion synthesis, ultrasonic pretreatment led to a pronounced reduction in crystallite size and particle agglomeration, accompanied by a significant increase in specific surface area. Under optimized conditions, MgO nanopowders with a high specific surface area of approximately 340 m2 g–1 and a narrow particle size distribution were obtained. The improved microstructural characteristics were attributed to cavitation-induced modification of precursor chemistry and more homogeneous combustion reactions. In addition, the functional properties of the synthesized MgO nanopowders were evaluated through antibacterial activity tests, demonstrating their potential applicability in advanced inorganic and functional materials.
Combustion wave dynamics were analyzed in a two-layer Ti–C–Cu system under SHS conditions. Utilizing equimolar Ti–C mixture with varying Cu amounts, the study showed that combustion temperatures surpassing the Cu liquidus drive interfacial metal migration and metallurgical welding. Variation in Cu content allowed for controlling the burning velocity, revealing that the refraction of the combustion wave front at the layer interface adheres to a relationship analogous to Snell’s law.
Solution combustion synthesis (SCS) to make few-layer graphene (FLG) from sucrose was demonstrated. Such a mass-producible and low-cost method is competitive as a candidate for industrial production of graphene. We used sucrose as a carbon source and ammonium nitrate as an oxidizing agent. The synthesized sample had a three-dimensional network and a porous structure with various kinds of sheets and sponge shapes, but after ultrasonication, it included lots of FLG. It was confirmed that the obtained production is highly defective and contains a large number of FLGs which don’t have enough bonding between them and can be easily separated. SEM, SPM, XRD, Raman, and BET analyses were carried out to confirm the characteristics of graphene, which prove 5–8 layers of graphene. The mechanical properties of nitrile butadiene rubber–graphene (NBR@FLG) composites were investigated by adding the synthesized FLG to NBR. It was confirmed that the addition of 0.5 phr of FLG to NBR increases tensile strength by 2.49 times, elongation by 2.28 times, and hardness by 1.66 times.
TiC-reinforced entropy-stabilized composites were synthesized via self-propagating high-temperature synthesis (SHS) in the Ti–Mn–Co–Ni–Al–C system and consolidated using spark plasma sintering (SPS) technique. Thermodynamic analysis predicted an adiabatic temperature of 1830 K, while experimental SHS reached 1550°C with rapid heating (1720°C/s) and cooling (2.8°C/s) rates. X-ray diffraction identified titanium carbide, FCC Ti–Mn–Co–Ni alloy, and minor amount of Mn2Ti intermetallic compound after the combustion synthesis. SEM/EDS revealed a porous, sponge-like SHS microstructure with bimodal particle-size distribution, evolving into a dense, well-bonded composite after SPS, with fine TiC uniformly dispersed in the metallic matrix. The intrinsic reactivity of SHS powders made them particularly suitable for spark plasma sintering, enabling rapid densification while preserving the fine TiC reinforcement and the entropy-stabilized FCC metallic matrix.
In this study, porous hollow cylinders based on β-SiAlON were produced via self-propagating high-temperature synthesis (SHS). The synthesis process involved two stages: (1) the preliminary structuring of a powder mixture of silicon, aluminum, and microsilica, with the incorporation of reinforcing basalt fibers into the porous reactive blanks, and (2) the nitridation of these blanks through SHS. The investigation examined the effect of the cylinder inner diameter on nitrogen content, burning velocity, maximum combustion temperature, porosity, gas permeability, compressive strength, and the phase composition of the products. The microstructure of the combustion products was also analyzed. For reaction blanks with an outer diameter of 90 mm, the combustion reaction could be initiated when the inner diameter was 50 mm or less. The porosity of the resulting β-SiAlON-based materials ranged from 49.5 to 51.8
Cast Ti–Cr boride composites with a Ni–Al–Mn binder were prepared via high-temperature synthesis to develop high-performance surfacing electrodes. It was revealed that the burning velocity and phase composition/microstructure of synthesized products are highly dependent on the initial reactor pressure and charge composition (CrO3/TiO2/Al/B2O3). A specific composite containing 15 wt
Manganese ferrite (MnFe2O4) is a technologically important soft ferrimagnetic spinel oxide with high saturation magnetization for magnetic and electronic devices. In this work, manganese ferrite (MnFe2O4) nanoparticles were synthesised by the solution combustion synthesis method using glycine as a reducing agent and the corresponding metal nitrates as oxidizers. By adjusting the fuel-to-oxidizer ratio, phase-pure manganese ferrite with a porous microstructure was obtained. In fuel-lean mixtures, the formation of Mn3O4, α-Fe2O3, and non-stoichiometric ferrites (Mn0.43Fe1.57)FeO and Mn0.202Fe0.798O was observed, whereas fuel-rich mixtures yielded single-phase manganese ferrite. Considering the minimal residual carbon content in the synthesized material (0.06
Fe2Mn3Si3-based alloy with minor cubic Heusler Fe2MnSi phase was prepared for the first time via self-propagating high-temperature synthesis. The reaction initiated at 668°C, reaching a maximum of 1115°C, indicating high exothermicity driven by Fe–Mn interaction. Room-temperature magnetic properties showed weak ferromagnetism (coercive force of 42 Oe and and remanent magnetization of 0.20 emu/g), attributed to paramagnetism of Fe2MnSi and impurity-induced disordering in Fe2Mn3Si3.
Induction (high-frequency) boriding of steel was performed at 1200°C using a novel combined charge of 30 wt
This study examines the influence of mechanical activation (MA) and initial titanium powder properties on forced self-propagating high-temperature synthesis (SHS) compaction of Ti–C mixtures. MA of pure titanium powder substantially elevated its oxygen content from 0.3 to 2.0 wt
CoCrNi–TiC cermet was synthesized by spark plasma sintering, resulting in the formation of secondary chromium-rich (CoCrNi)3C2 phase during consolidation. The cermet was found to exhibit a markedly enhancement in mechanical properties, achieving a Vickers hardness of 16 320 MPa compared to 2025–2332 MPa for CoCrNi, while preserving a fracture toughness of 8.12–10.60 MPa m1/2. This strengthening effect is directly attributed to the reinforcing role of TiC grains within the composite structure.
High-entropy nitrides have the potential to enhance mechanical properties and high-temperature stability compared to mono- or binary nitrides. They are particularly promising for applications requiring high temperatures and hardness. Here, we report on a facile one-step route for the fabrication of a high-entropy nitride powder (TiZrHfNbTa)Nx. The novel approach employs the mechanical alloying of metal powders within a planetary ball mill under elevated nitrogen pressure. Ball milling a mixture of five transition metals under a nitrogen pressure of 0.6 MPa for 60–90 min leads to the formation of a high-entropy nitride with a rock-salt crystal structure. The as-prepared powder exhibits nanoscale crystallites and a uniform distribution of metals within the cationic sublattice. The total nitrogen content of the synthesized powder is 8.9 wt
The effect of low-energy mechanical activation (LEMA) of 3Ni + Al powder mixtures on their ignition temperature was theoretically and experimentally investigated. LEMA proved instrumental in creating structural defects and significant morphological changes, thereby critically influencing subsequent high-temperature synthesis kinetics. It was determined that LEMA reduces ignition temperature by lowering chemical reaction activation energy and increasing the interfacial surface area. During the initial stages of activation, crystal defect formation served as the primary mechanism, raising the internal energy and lowering the ignition barrier. Extended activation led to prominent morphological transformations, including particle size reduction, decreased structural heterogeneity, and layered mechanocomposite formation. These alterations transitioned the reaction mechanism from diffusion-controlled to interfacial-controlled, subsequently lowering the required activation energy. The findings underscore the critical role of morphological evolution in enhancing system reactivity, especially under prolonged activation. This research establishes a scientific foundation for developing efficient methods to produce Ni–Al-based materials, highly relevant for high-temperature applications in the energy, aerospace, and chemical industries.
The regularities of carbonyl iron powder nitriding were investigated using Ti + C “chemical oven” mixture and urea as a source of atomic nitrogen. Increasing the urea content was found to lower maximum nitriding temperatures and decelerate cooling rates, the latter being attributed to the exothermic nature of iron–nitrogen reaction. Although maximum temperatures decreased as sample diameter was reduced, the phase composition exhibited minimal sensitivity to these geometric variations.
The combustion and ignition behaviors of W–PTFE powder mixtures, incorporating both tungsten micro- and nanoparticles along with high-energy additives, such as Ti, Ni + Al, Ti + 2B, and TiH2, were examined. Through thermodynamic and experimental analysis, it was determined that mixtures containing tungsten nanoparticles (nW) achieve 50–60
Mg2Si was prepared via self-propagating high-temperature synthesis. Characterization by XRD and SEM confirmed Mg2Si as a basis. The synthesized product density, porosity, electrical resistivity, and Seebeck coefficient were measured. Electrical resistivity showed a nonlinear, semiconductor-like dependence. Similarly, the Seebeck coefficient followed a nonlinear trend, reaching a minimum of –367 µV/K at 589 K.
The study focused on the synthesis of cerium and europium co-doped yttrium aluminum garnet (YAG) phosphors. Pure phase YAG:Ce,Eu powders were synthesized using a mixed fuel combustion method around 500°C furnace temperature. The crystallinity and luminescence spectra of YAG:Ce,Eu were examined.
A numerical investigation was conducted to explore the impact of external heat transfer on combustion wave propagation in a cylindrical Ti–Si layer, employing a solid-flame combustion model. Calculations revealed the average burning velocity of the sample, presenting it as a function of layer thickness, inner radius, and outer radius. Critical conditions for the synthesis process in the combustion mode of a hollow cylindrical sample, driven by environmental heat loss, were identified. In the near-critical synthesis mode, periodic temperature fluctuations arose within the combustion wave when the layer thickness was less than 0.5 mm. Conversely, for samples with a layer thickness exceeding 1 mm, combustion consistently proceeded in a stationary manner.
The present study explored the hydrogen storage properties of the Ti30V60Mn3.3Cr6.6 alloy. The alloy was synthesized using arc melting method and activated under dynamic vacuum for 2 h. The X-ray diffraction study confirmed the formation of a single-phase bcc structure. The Ti30V60Mn3.3Cr6.6 alloy exhibited a hydrogen absorption capacity of 3.61 wt
This study presented the formation and oxidation of refractory materials investigated with a high-speed electro-thermographic method specifically designed to probe rapid exothermic gas–solid reactions. Thin metallic wire specimens of Ta or tantalum carbide (TaC, Ta2C) coated Ta served as both heating elements and reactants, enabling controllable heating of specimen up to 5 × 105 K/s under various gas environments. Real-time measurements of electrical parameters and temperature at 10 kHz captured reaction dynamics across 900–2500 K. Two distinct heating modes were employed: (i) temperature-controlled (isothermal or linear heating) and (ii) power-controlled, which simulates quasi-isothermal reaction conditions. This dual approach allowed detailed exploration of TaC/Ta2C coating synthesis on Ta wires and identification of the critical parameters separating slow oxidation from ignition of tantalum and tantalum carbides. Gravimetric measurements provided kinetic data on carbidization and oxidation across varied experimental conditions, while rapid quenching of specimens preserved intermediate states for ex-situ characterization by X-ray diffraction and electron microscopy.
