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The possibility of obtaining a composite material from a ferroalloy based on silicon, aluminum, and zirconium nitrides by the method of self-propagating high-temperature synthesis is considered. It is shown that introduction of a nitrogen-containing additive on the basis of ferroalumosilicozirconium in amounts up to 35% to the initial ferroalloy leads to an increase in the nitrogen fraction, emission of the basic nitride phases in combustion products, deceleration of motion of the combustion wave front, and reduction of the maximum combustion temperature. It is found that introduction of a preliminary nitridized material in amounts of more than 20% makes it possible to convert combustion wave front propagation to a steady regime and to obtain combustion products with a macroscopically homogeneous composition. Under the conditions of natural filtration of nitrogen, combustion of a powder mixture based on ferroalumosilicozirconium and a nitridized material yields a composite consisting of AlN, Si₃N₄, ZrN, and α-Fe phases.

A study of the process of mechanochemical synthesis of titanium nitride under conditions of double mechanical activation of titanium powder: in argon and in nitrogen gas is presented. In the experiments, the time of mechanical activation of titanium in argon and nitrogen was varied. Analysis of the morphology of powder mixtures, X-ray diffraction and microanalysis data showed that preliminary mechanical activation of titanium in argon helps to accelerate the mechanochemical synthesis of titanium nitride. Analytical relationships are obtained and theoretical estimates are given that make it possible to predict the process of double mechanical activation of titanium.

The formation of compounds of refractory metal foils (Ti, Hf, Ta, Ni) with ceramic layers formed as a result of combustion of reaction tapes rolled from powder mixtures (Ti + 0.65C, Ti + 1.7B and 5Ti + 3Si) was experimentally studied. The microstructure, elemental and phase compositions of multilayer composites obtained by self-propagating high-temperature synthesis were studied using scanning electron microscopy and X-ray diffraction analysis. The influence of synthesis conditions (initial temperature, applied pressure) and the initial structure of the samples on the speed of propagation of the combustion wave front, microstructure, phase composition and strength characteristics of the resulting layered materials was revealed. It has been shown that connections in the combustion mode between metal foils and reaction tapes rolled from powder mixtures are ensured due to reaction diffusion, mutual impregnation and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The strength characteristics of the resulting materials (up to 275 MPa at 25 °C, up to 72 MPa at 1100 °C) were determined using a three-point loading scheme. The results are of interest for the development of structural materials operating under extreme conditions.

The effect of preliminary low-energy mechanical activation (MA) of nickel powder on the thermal explosion of the Ni₃Al intermetallic compound has been studied. Two synthesis methods are considered. In the first, the mixture was continuously heated by an external energy source. In the second, when the set temperature was reached, the external source was turned off. It has been shown that low-energy MA of nickel promotes the intensification of the synthesis of the Ni₃Al intermetallic compound. With continuous heating, the ignition temperature does not depend on the activation time and is equal to the melting point of aluminum. When heating with the external source turned off, preliminary activation of nickel reduces the solid-phase ignition temperature. It has been established that the activation of nickel in a laboratory mill allows one to avoid the factors of its passivation.

Boron is one of the most valuable fuels for rocket propellants. However, the boron oxide (B₂O₃) on the B surface has a high boiling point (1860 °C), which hinders the contact between the internal active B and the oxidation component during the ignition and combustion process. As a result, the ignition energy of B is higher and the combustion reaction rate is lower. In order to improve the ignition performance and reaction rate of B, a surface modification of B by means of surface purification by a solvent, surface grafting, and making a composite with aluminum (Al), which has a high combustion temperature, has been prepared. Composite particles of B purified by ethanol and thick flake Al (TF-Al), denoted by EB/TF-Al, have the fastest reaction rate higher by 96.6% than that of raw B and TF-Al composite particles (RB/TF-Al). Surface grafting of B with TF-Al composite particles (KHB-3/TF-Al) ensure the minimum ignition energy, which is 29.1% lower than that of raw B. As the ignition performance and reaction rate of B are improved by means of surface modification, the performance of B-based rocket propellants is expected to be improved.

The widespread use of flat electric heaters in technology and household appliances requires the search for simpler and cheaper technologies for their production. This work proposes a method for producing an electrically conductive coating (NiAl) and an electrically insulating layer (glass ceramics) in one stage - by the method of self-propagating high-temperature synthesis (SHS) in a thermally conjugated powder system (Ni + Al)/(PbO₂ + B + Al₂O₃ + glass). The process of propagation of the combustion wave front has been studied, the influence of layer thickness, the ratio of components in the powder mixture PbO₂ + B + Al₂O₃ + glass on the propagation speed and temperature of the wave front has been studied. combustion. An expansion of the wave front of the exothermic process was discovered when a mixture of PbO₂ + B was added to the lower layer. The addition of this mixture makes it possible to reduce the thickness of the NiAl layer and ensure the formation of a uniform dielectric coating. The phase composition and microstructure of the coating were studied. The optimal ratios of layer thicknesses and the composition of the powder mixture of layers have been established. The fundamental possibility of forming an electrically conductive and dielectric coating by the method of self-propagating high-temperature synthesis in one stage is shown.

Model expressions for the concentration diffusion coefficient and thermal diffusion factor of a binary mixture obeying the van der Waals equation of state are obtained. Model calculations at elevated pressure (density) require the equation of state parameters and thermal diffusion factor of the mixture in a low-density ideal gas state. The behavior of model relations is studied depending on pressure along isotherms. Near the critical state, the model diffusion coefficient has a minimum, and the thermal diffusion coefficient has a maximum. The diffusion and thermal diffusion models at elevated pressure are compared with experimental data for a number of mixtures. It is shown that they are in qualitative and generally quantitative agreement at different temperatures and concentrations of components. The van der Waals equation is not quite suitable for describing the experiment on compressibility and phase equilibrium at high pressure. This requires more complex and flexible modifications of the equation. Generalized expressions for model characteristics of the diffusion of the binary mixture in the case of such equations of state are given.

A three-dimensional model for a burner is established, and effects of gas nozzle structural parameters on the combustion performance of the burner are studied. With a change in parameters, the reverse flow zone in the furnace changes obviously. The interaction and symmetry of the four reverse zones directly affect the flame stability. The change in the maximum and average temperatures in the furnace is not the main reason for the increase in NO_x emissions at the furnace outlet (M_NO). Most probably, the increase in M_NO is caused by the characteristics of the high-temperature area. In ten cases studied, the NO_x emissions are all lower than 30 mg/m³ and even lower than 10 mg/m³ in some cases (under normal conditions), which indicates that the ultra-low nitrogen emission of the boiler can be achieved by reasonably modifying the nozzle structure

Propylene oxide (C₃H₆O) is an intermediate product of oxidation of heavy hydrocarbons and can be used as an additive to conventional fuels to reduce soot emissions. New experimental data on the oxidation of C₃H₆O at low temperatures were obtained using an isothermal jet-stirred reactor. Experiments were carried out at temperatures of 600-1300 K and a pressure of 1 atm, and the residence time of the gas mixture in the reaction vessel was 1 s. Five detailed chemical kinetic mechanisms taken from the literature were tested. A mechanism that has the best predictive ability at low temperatures was identified. The mechanisms were also tested against experimental data on the structure of C₃H₆O flames. It has been found that at the moment there is no model that can correctly describe the combustion and oxidation of C₃H₆O at both low and high temperatures.

An economical method for numerical simulation of natural excitation of gas vibrations in low-emission combustors of gas turbine units has been developed and tested. The method is based on the use of the SAS SST k-ω turbulence model and the turbulent combustion model with a modified equation for a variable degree of combustion completion. To model the natural excitation of gas vibrations, a factor associated with gas pressure pulsations is introduced into the source term of this equation. Isolation of one of the modes of gas vibrations prone to natural excitation is carried out using a resonant filter operating in each cell of the computational domain. The results of the computational study obtained using the proposed method make it possible to study the influence of design measures and operating parameters of natural vibrations and to approach more rationally the choice of measures to suppress them.