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Our recent results on application of 4D laser printing to preparation of porous core-shell polymer structures containing encapsulated micro and nanoparticles are overviewed. Thus prepared polymer-matrix nanocomposite can find their application in micro/nano-electromechanical systems. Synthesized highly porous nanocomposites can also be used in catalysis, lab-on-chips, hydrogen storage devices, surgery medicine, and drug delivery systems.

–The gas-sensing properties of nickel ferrite (NiFe2O4) and nickel oxide (NiO) nanoparticles prepared by a self-sustaining levitation-jet synthesis (LJS) method are reported. These have been compared to the gas-sensing properties of a NiO sensor prepared using a commercially sourced powder. The microstructure, surface area, particle size, and morphology varied widely across the sensors fabricated. It was anticipated that these contrasting properties would play a key role in either enhancing or worsening the sensing capabilities of the materials. Gases of interest included ethanol, toluene, and carbon monoxide as well as the gas response of the sensors was investigated at different operating temperatures. In general, the sensors responded to gases with different degrees of sensitivity. Among the sensors with higher surface areas, one provided noticeable enhancements in sensitivity towards gases when compared, for instance, to the sensitivity of the commercially based NiO sensor. The NiFe2O4 sensor presented most promise as a gas sensor to ethanol and, to a greater or lesser degree, towards toluene gas. In general, sensors were poorly responsive to the carbon monoxide concentrations tested. This study is one of the first reports of using LJS-based powders for gas sensing applications and it highlights the suitability of the method to fabricate size- and shape-controlled nanomaterials for the detection of environmentally relevant gases.

The catalytic properties of Inerton-supported nickel nanoparticles in benzene hydrogenation have been studied; rate constants of the reaction at different temperatures have been calculated. Activation energy and conversion have been determined, and the effect of size of nickel nanoparticles on their catalytic properties in benzene hydrogenation has been discussed.

We have studied conditions for the synthesis of intermetallic phases in the Cu–Al–Ni system by selective laser sintering/melting, in particular by heating a powder mixture to 300°C. The effects of laser synthesis and heating on the microstructure of the intermetallic phases in the samples obtained have been studied using electron microscopy, optical metallography, and X-ray diffraction analysis. The results demonstrate high sinterability of stoichiometric mixtures. Resistivity measurements indicate that the samples exhibit a shape memory effect. We discuss the feasibility of producing biomicroelectromechanical systems using layerby- layer synthesis.

MgNi2 intermetallic was synthesized by powder metallurgy and crystallizes with a Laves-type C36 structure (space group P63/mmc (No. 194); a = 4.826; c = 15.832 A). At 300 °C during interaction with hydrogen (deuterium) gas compressed to 2.8–7.4 GPa, a trihydride MgNi2H(D)3.2 was synthesized. The trihydride remained metastable at ambient conditions allowing its structure, stability and magnetic properties to be studied. The formation of MgNi2H3.2 is associated with a complete rebuilding of the initial hexagonal structure into the orthorhombic distorted MoSi2-type sublattice (space group Fmmm (No. 69); a = 4.55; b = 4.69; c = 8.80 A). Neutron diffraction of the MgNi2D3.2 demonstrated that D atoms fill sites having octahedral Mg4Ni2 (D1/4b) and planar Ni2 (D2/8f) coordination. Within the framework of the density functional theory, density of states (DOS) calculations showed the formation of a structure around −10 to −6 eV caused by the chemical bonds of hydrogen and its 1s states mainly via interaction with the 3d states of Ni. Analysis of the electronic structure revealed a charge transfer from Mg to Ni, and to the H atoms. The calculated enthalpy of formation of MgNi2H3 is about −30 kJ/mol-H2, which is consistent with the stability of the hydride at normal conditions. The initial sample contained a small amount of a secondary MgNi3 intermetallic, which has been formed during the equilibrium interaction of magnesium and nickel at 800 °C. Thus this compound should be included in the phase diagram of the Mg–Ni system. MgNi3 decomposes under high-temperature/high-pressure hydrogenation conditions and forms nickel monohydride.

The mechanical activation (MA) of a charge of a hard magnetic 22Kh15KT alloy is studied by wet and dry milling in a planetary mill in a medium of argon and ethyl alcohol with addition of surface-active materials and without them. It is shown that, upon dry MA, powder alloy components are alloyed with formation of two bcc solid solutions and, upon wet MA, charge particles are only intensely dispersed. Dispersion is developed at the highest degree in the first five minutes of MA.

Spherical zinc particles ranging in average size from 275 to 760 nm and covered with platelike zinc oxide particles on the order of 10 nm in size have been prepared by levitation-jet aerosol synthesis through condensation of zinc vapor in an inert-gas flow. The nanoparticles have been characterized by transmission electron microscopy, X-ray diffraction, BET measurements, and vibrating-sample magnetometry. The results indicate that the observed ferromagnetic ordering is due to changes in unit-cell volume on the surface of the nanoparticles. High-temperature magnetization data demonstrate that the ferromagnetic ordering of the nanoparticles persists up to 750 K.

Ferromagnetic Ni nanoparticles were formed by a levitation-jet aerosol synthesis under different gas environments and metal precursor feed rates. At a constant background gas inlet temperature, it was found that a higher Ni loading resulted in enhanced particle growth through coalescence. He partial atmosphere favors surface condensation of evaporated Ni atoms over coalescence as the surface area reduction mechanism in the nanoparticles. A flow of 2.5% air in the background gas mixture was enough to oxidize 75% of the initial Ni load, inducing a drastic destabilization of particle size and shape distribution. Regardless of the background inert gas composition, necked nanoparticles were observed in samples prepared with a 1 g/h Ni feed rate, whereas discrete nanoparticles resulted from a higher feed rate of ca. 4 g/h, confirming the key role of Ni loading on the rate of coalescence. The highest saturation magnetization (51.75 A m 2 kg −1 measured at 300 K) and the lowest coercivity (0.008 T) were obtained under an Ar flow. Zero-field cooled and field-cooled magnetization curves measured under an applied field of 10 −2 T revealed that the blocking processes of nanoparticles are dominated by their particle size distributions, with some features attributable to interparticle interactions.

The relative cross sections of processes taking place when H+ and He2+ ions with an energy of 6z keV (z is the ionic charge) capture an electron from molecules of C5H11NO2S methionine (proteogenic amino acid) and C6H13NO2 norleucine (nonproteogenic amino acid) are measured by time-of-flight mass spectrometry (a methionine molecule transforms into a norleucine molecule by substituting the CH2 group for the S heteroatom). The fragmentation pattern of resulting molecular ions is established from correlation analysis of the detection times of all fragment ions. The results are compared with experimental data for fragmentation of the same molecules ionized by electrons and photons. In these amino acids, the pattern of molecular ion fragmentation is found to depend on the type of molecule ionization. However, the detachment cross section of the COOH neutral group or residue (neutral or charged) R of a side chain of the amino acid is invariably among the largest. The relative cross sections of capture with single and double ionization of molecules are measured.

Nickel oxide nanoparticles (NPs) 6–24 nm size have been prepared by a levitation-jet method based on metal vapor condensation in a mixture of gaseous streams of helium and air (or oxygen). Particles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) N 2 adsorption and SQUID magnetometry. It is revealed that at room-temperature (RT) the nanoparticles show a small magnetic moment and the magnetic field dependence of their susceptibility a minimum lying below the high-field values. After the appropriate subtraction of both ferromagnetic and paramagnetic components from the initial magnetization curves, the appearance of a diamagnetic contribution is observed. The possible link between the latter contribution and the occurrence of some features related to RT superconductivity in NiO NPs is discussed.

Pseudospherical copper ferrite particles 20 to 90 nm in average size were prepared by an aerosol method through condensation of iron and copper vapors in an inert-gas flow, followed by the oxidation of the resulting two-phase powder under heterogeneous combustion conditions to an almost single-phase product. The nanoparticles were characterized by scanning electron microscopy, X-ray diffraction, BET measurements, and vibrating-sample magnetometry. Analysis of the X-ray diffraction data and the behavior of the magnetization of reaction intermediates and final synthesis products in the range 400–1100 K made it possible to propose models for the nanostructure of the particles and establish the likely sequence of the observed phase transformations.

Pseudospherical nickel ferrite particles 25 to 70 nm in average size were prepared by a crucibleless aerosol method through cocondensation of Fe and Ni vapors in an inert-gas flow containing a small amount of air. The particles were characterized by transmission electron microscopy, X-ray microanalysis, X-ray diffraction, BET measurements, and vibrating-sample and SQUID magnetometry. The results were used to optimize process parameters for the preparation of particles with a tailored size, specific surface area, and saturation magnetization. A dc electric field applied to the condensation zone can serve to improve the phase purity of nickel ferrite nanoparticles, reduce their size, and change their Curie temperature.

The time-of-flight mass spectrometry method is used to study processes occurring when 36-keV multiply charged Ar ions (Ar6+) capture electrons from adenine and uracyl molecules. Adenine and uracyl constitute one of two base pairs entering into the RNA composition. The fragmentation scheme of resulting molecular ions is derived by analyzing correlations between the detection times of all fragment ions. Fragmentation patterns for molecular ions resulting from molecule ionization by photons, electrons, protons, and multiply charged ions are compared.

For the first time, complex oxide NaFeYO7 + x was prepared by SHS (T c = 750–1200 K, U = 1–4 mm/s) in the Na-Fe-Y-O system. Explored was the influence of reagents ratio on combustion limits for the mixtures under study. Combustion products were characterized by XRD, SEM, EDX, chemical analysis, and magnetic measurements. Single-phase NaFeYO7 + x was obtained at an excess of sodium in green mixtures. To stabilize the product, the water-washing procedure was used just after synthesis. The synthesized material has a cubic crystal structure with a cell parameter close to that of sodium yttrate NaYO2, it exhibited very weak magnetic properties, and overly-stoichiometric oxygen content. The product is heat resistant up to 450 K. The synthesized product is a new inorganic superoxide with good technological perspectives for use as a solid oxygen-containing material.

Time-of-flight mass spectroscopy methods are employed for studying processes occurring during capture of electrons by 3He2+ and Ar6+ multiply charged ions with energy 6z keV (z is the ion charge) from C2Hn molecules (n = 2, 4, 6) with different multiplicities of C-C bonds. Fragmentation schemes of the molecular ions formed in such processes are established from analysis of correlations of recording times for all fragment ions. The absolute values of the cross sections of capture of an electron and capture with ionization are measured, as well as the cross sections of formation of fragment ions in these processes. The absolute values of total capture cross sections for several electrons are determined.

Selective laser sintering (SLS) process was used to prepare nanostructured porous 3D items consisting of Ni or/and Cu nanoclusters embedded into a polycarbonate (PC) matrix for potential use in nanoelectromechanical systems (NEMS). Liquid-phase SLS was performed (in air or Ar) with the Ni-PC powder mixtures taken in proportions of 1 : 1, 1 : 2 (Ni particle size 27–184 nm) and Cu-PC powder mixtures (1 : 9, 1 : 4, 3 : 7, Cu particle size 76–90 nm) using a cw YAG : Nd+3 laser (P = 4–10 W) and a scanned spot of slightly defocused beam. After sintering, the size of starting nanoparticles remained unaffected. Demonstrated was the feasibility of SLS production of functionally graded 3D items, which opens up a way to direct synthesis of NEMS devices. Process conditions for preparation of monolayers and 3D items were optimized. Functionally graded 3D items with alternating ferromagnetic Ni-PC and non-magnetic Cu-PC layers exhibited interesting electrophysical and magnetic properties.

The effect of a 0.2 T external magnetic field on the heterogeneous combustion of a mixture of iron metal and oxide (Fe2O3) system with solid oxidizer (NaClO4) was studied. Time-resolved X-ray diffraction (TRXRD) was used to study the kinetics of intermediate product formation and thermal imaging experiments to measure the reaction temperature and velocity. Metastable fcc iron phase formation was discovered as an intermediate predominantly in applied field reactions.

The behavior of frontally burning heterogeneous systems containing boron, aluminum, gallium, indium, yttrium, lanthanum, and ytterbium is studied by a potentiometric method. These systems are used for self-propagating high-temperature synthesis of some oxide materials. The peak values of the electromotive force of combustion arising between the combustion wave front and the synthesis products in systems with participation of triple-charged ions of these chemical elements are found to be directly proportional to the ionic potential of the chemical element and reach 150–400 mV. The use of two heteropolarly reacting systems as elements of the electromotive force of combustion in one array assembly allows the difference in potentials to be increased to 2.3 V.

Spherical oxidized nickel particles 15 to 200 nm in average size have been produced by a crucibleless aerosol method involving metal vapor condensation in an inert gas flow and oxidation processes. The particles have been characterized by scanning electron microscopy, X-ray microanalysis, X-ray diffraction, BET surface area measurements, and vibrating-sample magnetometry. The process parameters have been optimized for the preparation of particles with tailored size, specific surface area, and saturation magnetization. A dc electric field applied to the condensation zone during the oxidation process reduces the size and increases the extent of oxidation of the particles. We have studied low-temperature oxidation of carbon monoxide and propane on nickel nanopowders differing in particle size and extent of oxidation. The nanoparticles with optimized characteristics have been shown to have a marked catalytic effect on these processes.

Overviewed are new experimental methods for investigating the processes of phase formation during SHS. The first experiments using penetrating synchrotron radiation and energy dispersive detectors for different classes of complex inorganic materials were carried out in ESRF (Grenoble, France), LURE (Orsay, France) and Daresbury (UK). A new and very sensitive thermal imaging method (Thermal Imaging Technique, TIT) is based on continuous registration of the whole combustion process by using a highly sensitive IR camera and software developed by MIKRON Instruments Co. (USA) was also used for precise registration of combustion parameters. SHS was performed on different types of pure on doped complex inorganic materials in pellet and powder form in a range of dc magnetic field induction up to 20 T and electrical field strength up to ±220 kV/m. The dc magnetic field was applied during the reaction, supplied either by permanent magnet (transverse, 1.1 T) or by an electromagnet (longitudinal, up to 20 T). The dc electrical field was applied along direction of the combustion wave propagation. The combined processes of SHS and SLS (Selective Laser Sintering) of 3D articles for different powdered compositions was realized with optimal parameters of laser irradiation, under what SHS reactions proceeded in controlled regime.

The effect of a contactless electric field on the interactions involved in the combustion of the BaO2-Fe and MnO2-Fe systems is studied. The results are indicative of the possibility of increasing the extent of chemical conversion during the combustion of oxide systems by applying an external electric field. A possible mechanism of the influence of an electric field on the redox processes occurring during the combustion of oxide systems composed of a metal fuel and a solid oxidizer is described.

The comparative microstructural analyses and histomorphological studies of tissue reactions to porous titanium and nitinol implants synthesized by Selective Laser Sintering (SLS) are presented for a rat model for bone implants. It was discovered that the surface of porous pegs of titanium and nitinol made by SHS/SLS has a significantly favorable structure to the mechanical interlocking with bone and soft tissues. Histological analysis of decalcified paraffin sections after implant removal could only show that trabecular bone structures and marrow cavities were observed around the porous implants. In the connective tissue of the remaining implant beds the following cells: macrophages, fibroblasts, adipocytes and lymphocytes are discernible. It was shown that the nitinol synthesized by combined SHS/SLS technique has a developed and ordered microstructure.

The mutual influence of barium peroxide and sodium perchlorate on thermolysis of the (2 ⎯ x)BaO2-xNaClO4 system (x = 0-2.0) has been studied. It has been demonstrated that the use of the physicochemical mechanism of this influence makes it possible to carry out heterogeneous combustion in complex oxide systems in the controlled regime by changing the mutual concentration of solid inner reaction oxidizers. An explanation of the thermal and kinetic effects in the thermolysis of the peroxide-per� chlorate system has been suggested. Alkali metal chlorates and perchlorates decompose on heating to evolve oxygen. This makes them suitable for using as oxygen sources in oxidation reactions, including the selfpropagating hightemperature syn� thesis (SHS) of complex oxides, which requires the presence of a fuel and oxidizer in the reaction system (1, 2). In the SHS of complex oxide materials, solid inner reaction oxidizers, such as sodium perchlorate NaClO 4 , can be used as an alternative or complement to gaseous oxygen. Sodium perchlorate contains more than 50 wt % of oxygen, which is completely evolved at relatively low temperatures (3). However, in the com� bustion reaction, the time interval of the vigorous oxy� gen evolution from the solid oxidizer may not coincide with the intense exothermic oxidation reaction (com� bustion) of the metal component. If this is the case, the chemical reaction rate significantly decreases, which leads to incomplete reaction of the components and even to combustion failure. The kinetic parame� ters of sodium perchlorate thermolysis can be changed by both external physical actions (for example, electric field (4)) and various chemical additives. As is known, small additions (up to 4 wt %) of some metal oxides catalyze the thermolysis of potassium perchlorate and sodium chlorate (5). Inasmuch as metal oxides are components of reaction mixtures for the SHS of complex oxide materials, if the character of the influence of some oxide on perchlorate is known, it is possible to find the bath composition at which the process will be controllable and will proceed at defi� nite rates and temperatures. In SHS processes, alkali metal and alkaline earth peroxides are often used as oxide components. For example, barium peroxide BaO 2 is used in the synthesis of hightemperature superconducting ceramics (HTSC—YBa2Cu3O 7- x), barium hexaferrite (BaFe12O19), barium stannate (BaSnO 3 ), etc. In these systems, the fuel is a powder of a corresponding metal: iron, copper, and tin. Thus, to determine optimal component ratios when sodium perchlorate is used as a solid inner reaction oxidizer, it is necessary to know the mechanism of the influence of superstoichiometric NaClO4 , as a chemical addi� tive, on the synthesis in these systems. To determine this mechanism, we considered the mutual influence of NaClO4 and BaO2 on thermolysis of these com� pounds in the reaction mixture.

The behavior of frontally burning heterogeneous systems containing chromium, molybdenum, and tungsten, which are used in the self-propagating high-temperature synthesis of complex oxide materials, was studies by the potentiometric method. It was revealed that the peak emf between the combustion wave front and the synthesis products can be as high as 2 V, depending on the chemical composition of the initial stock. A mobile registering probe moving with the velocity of combustion wave propagation makes it possible to substantially increase the time of emf recording

A new approach to power engineering modeling in a weak electrically conductive dynamic medium with induction fields was developed. The optimum induction field energy for moving liquid-gas systems in which chemical transformations takes place was estimated. For these systems, the dynamics of Joule energy dissipation and pondermotive action distributions was found to depend on the induction field frequency and movement velocity.

Fullerite with the bulk formula ArxC60, where 0.60 < x < 0.75, was synthesized by precipitation from a mixture of argon-saturated solutions. The fcc unit cell parameter in the sample was 1.422 nm; the orientational phase transition (OPT) temperature was 247 K. These values noticeably differ from the relevant parameters of undoped fullerite (1.416 nm and 260 K, respectively). Heating accompanied by argon evolution restores the fullerite C60 structure.

For fullerite C60 with intercalated oxygen, a sharp (by three orders of magnitude) increase in the intensity of the EPR signal with a g-factor of 2.0024 was observed at ∼200°C. Studies of gases formed in heating of the sample in a vacuum showed that molecular oxygen was largely released at temperatures below 100°C, whereas the gas phase formed as the temperature increased to 200°C contained carbon oxides CO and CO2 in addition to oxygen. The conclusion was drawn that the intensity of the EPR signal was determined by the products of oxygen interaction with fullerene rather than the concentration of oxygen in the sample.

Three-dimensional parts with a wide range of properties were synthesized by combining together self-propagating high-temperature synthesis (SHS) and selective laser sintering (SLS). Different powder mixtures were investigated for producing piezoceramics, ferrites, and the high-temperature superconductor. Changing the structure, volume fraction, phase, and pore-distribution within the composite optimized the physical properties. The optimum regime for laser synthesis and some of their associated electro-physical properties were determined by changing the laser parameters, as well as, by conducting the reactions in an applied dc magnetic field. The mechanical properties and the ability to influence the Shape Memory Effect in synthesized porous NiTi were also studied. Stress-strain, X-ray, scanning electronic microscopy (SEM), and energy dispersive analysis by X-rays (EDAX) characterization data were shown to be dependent on laser irradiation parameters. A comparative study of bone-integration with porous NiTi implants was conducted.

Fullerite C60 with intercalated CH2F2 (Freon-32) was prepared for the first time. The sample was studied by elemental analysis, X-ray powder diffraction, mass spectrometry, and IR spectroscopy. The composition of the sample was found to be (CH2F2)C60. The sample had a face-centered cubic lattice with the lattice parameter (1.4284 nm) much larger than that of pure fullerite (1.416 nm). The gas released from the sample during heating in a vacuum to 450°C largely consisted of initial Freon (mass spectrometry data); no Freon destruction products were observed at this temperature. The C-F stretching vibration frequency (1058 cm−1) was shifted in (CH2F2)C60 by 30 cm−1 toward lower wave numbers compared with the gas phase. The absorption bands at 1182 and 1428 cm−1 (IR active modes (F1u) of high-symmetry (Ih) C60 molecules) did not change their positions in the intercalate.

Radiation-produced defects in doped and nominally undoped n-GaN with charge carrier concentrations in a range of 4 × 10 16 cm -3 to about 2 × 10 18 cm -3 are investigated. Layers of n-GaN are irradiated with fast electrons at 0.9 MeV, 60 Co gamma rays and protons at 150 keV. The production rates of radiation defects in n-GaN are estimated and compared with literature data. Annealing processes of radiation defects in n-GaN in the temperature range 100-700 °C are also discussed. The annealing behavior appears to be complicated. Two temperature intervals, from T= 100 to 400°C and from T = 500 to 700°C, are characteristic for modification and annealing processes of radiation-produced defects in n-GaN.

We have prepared ferromagnetic barium hexaferrite powders by self-propagating high-temperature synthesis (SHS) in an electric field applied by a contactless method. Our results indicate that the field strength has a significant effect on the phase composition of the synthesis product. This effect is interpreted in terms of the decomposition kinetics of the solid oxidant and reactant diffusion. Microstructural examination demonstrates that an electric field has a marked effect on the morphology of SHS materials. The magnetic properties of the synthesized powders depend significantly on both the strength and direction of the applied field.

Two methods are described for doping of fullerite C60 with molecular oxygen at a pressure of ∼104 Pa and at temperature 20–30 °C. It was found by mass spectrometry using oxygen 18O as dopant that a portion of molecular oxygen absorbed by the pre-decontaminated fullerite (first method) is removed as CO and CO2 at the heating temperature ≤200 °C. Doping during fullerite precipitation from the liquid phase (second method) makes it possible to prepare samples with the oxygen content ≥1.2 at.%. The fullerite doped with oxygen to this level is diamagnetic. The paramagnetic properties of an O2 molecule disappear when O2 is incorporated into the fullerene lattice. This is interpreted on the basis of quantum chemical calculations as a sequence of equilibrium formation of the adduct C60O2. Calculations showed that the subsequent chemical transformation of C60O2 resulting in the O-O bond cleavage is energetically favorable, enabling prerequisites for the formation of products of incomplete (CO) and deep (CO2) oxidation of fullerene under mild conditions.

The dependence of the lattice parameters of the chromium oxide Cr2O3 formed in a wave of heterogeneous combustion of chromium (chromium oxide) with sodium and potassium perchlorates on the initial ratio between the fuel and oxidant is established. A new cubic phase of chromium oxide with the lattice parameter close to that of the sodium superperoxide phase is found in the combustion products. The role of the gaseous components in the formation of new phases in the chromium oxide obtained by heterogeneous combustion is determined.

Using the synthesis of manganese ferrite as an example, it is shown that an electric field causes a significant change in the parameters of heterogeneous combustion, depending on the field strength and application direction. The possible factors determining the end burning of the starting mixture in the applied electric field are considered.

The interaction of sintered hematite Fe2O3 with melts in the PbO–SiO2 system at 900°C and melts in the Na2O–SiO2 system at 1150°C is investigated by the annealing–quenching technique with the use of standard physicochemical methods (X-ray powder diffraction analysis, scanning electron microscopy, quantitative X-ray microprobe analysis). The melting diagrams of the PbO–Fe2O3–SiO2 and Na2O–Fe2O3–SiO2 systems are calculated and constructed on the basis of the model of regular solutions. An analysis of the experimental and calculated data demonstrates that the diffusion dissolution of hematite at the “hematite–melt” heterogeneous interface can be observed only for the PbO melt. For lead and sodium silicate melts, the diffusion process is accompanied by the concurrent redox reaction with the liberation of gaseous oxygen, which appreciably promotes the erosion of solid hematite.

Cerium chromites, non-substituted and substituted with alkali-earth metals, are synthesized in the self-propagating high-temperature synthesis mode using solid interaction oxidizes. The characteristic temperatures and specifics of interaction between the components are determined for all systems considered. The structural and physicochemical parameters, including the spectroscopic characteristics of the synthesis products depending on the alkaline-earth metal substituent and the degree of substitution, are investigated.

Refractory composites MgCrO4 + Mg + MgO and MCrO4 + Al + Al2O3 (M = Mg, Ca, Ba) prepared by self-propagating high-temperature synthesis (SHS) are studied in model experiments, and their properties and conditions for SHS combustion reactions are discussed.

The possibility of implementing a reaction of self-propagated high-temperature synthesis of ferrites controlled through selective laser treatment is demonstrated. The conditions of synthesis of barium hexaferrite with a chromium additive and the effect of additional annealing on the results of synthesis are investigated. The three-dimensional ceramic products obtained have sufficiently good consumer properties.

The electrical resistivity of TiB2–AlN–BN ceramics with Y2O3 additions was measured between 300 and 1300 K as a function of the Y2O3 content of the starting mixture. The resistivity of the ceramics was found to exhibit anomalous, hysteretic behavior in a wide temperature range. This behavior is tentatively attributed to the metastability of percolation processes in the multicomponent conductive ceramics.

The ZrO2–FeO x melts prepared by induction melting in a cold crucible in air are investigated experimentally. It is found that the immiscibility region exists in the liquid phase. The theoretical fusibility curves (calculated according to the authors' DIATRIS 1.2 program) for the ZrO2–FeO–Fe2O3 system are compared with the experimental temperatures of the formation of the secondary phase, liquidus and solidus lines, and X-ray microprobe spectroscopic and X-ray powder diffraction data for quenched and slowly cooled samples. It is demonstrated that the immiscibility region in the liquid phase in an air atmosphere is observed in the temperature range 1870–2230°C and the concentration range 34–82 wt % ZrO2 .

Hydrofullerites C 60 H x synthesised at hydrogen pressures of 0.6 and 3 GPa were found to possess ferromagnetic properties at room temperature. The magnitude of magnetisation varied from sample to sample and reached 0.001–0.16 Bohr magnetons per C 60 molecule at H =10 kOe. The coercivity of all the samples was about 100 Oe. The hydrofullerites had either an fcc or bcc lattice formed of C 60 H x units. The maximum values of magnetisation were observed for the fcc hydrofullerites with x ≈24.

We suggest two approaches to collecting the electromotive force (Ec) generated by SHS reactions such as the use of mechanical systems with a movable voltage-collecting electrode and the so-called battery assembly. The use of the battery system comprising of two reactive systems generating voltage of opposite polarity afforded to increase Ec up to 2.3 V.

Alkali metal perchlorates are known as oxidizers widely used in propellants, pyrotechnics, catalysts, and other fields [1]. These compounds contain significant proportions of oxygen, so they can also be successfully employed as solid oxidizers in the self-propagating high-temperature synthesis (SHS) of functional oxide materials (ferrites, ferroelectrics, high- T c superconductors, and others) [2]. In the combustion synthesis of complex oxides, the quality of the ultimate product is significantly affected by the degree of coincidence of the peak of perchlorate decomposition with oxygen gas evolution and the peak of metal fuel oxidation [3]. Usually, numerous test-and-trial experiments are needed to solve this problem and to find an optimal batch composition. In this context, it is pertinent to search for means of controlling such processes, especially for distant control means. It was discovered that, for example, strong electric fields generated by a condenser under SHS conditions substantially change the combustion process parameters [4]. The magnetic parameters of some ferrites are substantially modified during SHS in electric fields. To explain the effect of external physical actions on combustion and phase formation during the synthesis of complex oxide materials, it was hypothesized that electromagnetic fields applied to the zone of intense chemical reactions affect the kinetics of the decomposition of solid intrareaction oxidizers [5]. In addition, it cannot be ruled out that such actions affect oxygen exchange during the formation of complex oxides. In order to elucidate possible effects of electric fields, we believed it important to recognize the major SHS stages and to analyze the field effects on each stage. In this context, by way of example we studied the decomposition kinetics in electric fields for pure sodium perchlorate. The experimental setup used to study sodium perchlorate thermolysis (Fig. 1) was a vertical furnace equipped with a kanthal wire heater, with two tubular chambers 20 mm in inner diameter. The furnace was mounted between two copper plates, which were isolated with Teflon liners 1 mm thick and to which voltage up to 25 kV could be applied. Crucibles 18 × 24 mm in size, one containing powdered sodium perchlorate and the other containing a reference (NaCl), were simultaneously inserted into the chambers preheated to the required temperature ( 750°C ). Chromel‐ Alumel thermocouples were embedded beforehand into the powder to a depth of about 3 mm. Thermocouple signals were recorded with a potentiometer equipped with an xy plotter. Sodium perchlorate (99+%) from Acros Organics pounded in an agate mortar with a pestle was used in the experiments.