Technical features and examples of the practical use of technology of combined hardening treatment of steel tools are presented, which includes (1) hardening thermal cycling treatment (HTC) of tool blanks and (2) thermo-hydro-chemical treatment (THCT) of the finally manufactured instruments. THCT creates volumetric hardening of tools by thermal cycling with incomplete solid-phase α ↔ γ transformations, followed by quenching and tempering. HTC creates surface hardening of tools by boiling refractory compounds in hydrosols followed by tempering. As a result of combining THCT + HTC, the service life of cutting steel tools increased by 2–20 times, and that of die tools by 1.9–2.1 times compared to traditionally hardened tools.

The effect of irradiation with helium ions with energy of 40 keV and doses from 1 × 1014 to 2 × 1017 cm–2 on the microstructure and phase composition of ceramics based on silicon carbide is studied. Radiation growth of the 6H–SiC crystal lattice is revealed. At a dose of 1 × 1016 cm–2, a decrease in deformation is observed related to the formation of gas-vacancy clusters, which are sinks for radiation defects. Amorphization of the near-surface layer is established.

The results of studies on the zirconium crystal structure after initial stages of oxidation in an open air at temperature of 700°C for 15 min are presented. Samples of commercial pure zirconium with a minimal content of impurity atoms as well as chromium-alloyed zirconium have been studied by means of the action of compression plasma flows. The possibility of alloying the zirconium near-surface layer with chromium, with a chromium coating thickness of 1 μm, by means of compression plasma flows with the absorbed energy density of 25–43 J/cm2 has been demonstrated. Stabilization of the high-temperature zirconium β phase in the form of β-Zr(Cr) solid solution and intermediate martensite α'-Zr phase has been observed. After isothermal annealing of zirconium samples at T = 700°C and irradiated with plasma flow with Qmax = 43 J/cm2, no effect of the surface layer alloying with chromium atoms has been observed owing to its intense evaporation and ablation in the course of surface heating by plasma flow, as well as increased resistance to high-temperature oxidation at the initial stages in comparison with the initial state.

The paper presents the results of a study of the microstructure, elemental and phase compositions of the eutectic alloy (wt %): Al–12.5 Si–0.8 Mg–0.4 Mn–0.7 Fe–0.9 Ni–1.8 Cu. A comparison of the microstructure of the alloy obtained at melt cooling rates of 102 and 105 K/s is made. It is shown that an increase in the melt cooling rate leads to the refinement of structural components, a decrease in the volume fraction of primary α-Al dendrites, an increase in the volume fraction of a mixture of eutectic silicon and aluminum, and a decrease in the silicon concentration in the interdendritic space from 23 to 13 wt %. Using energy-dispersive analysis and X-ray diffraction analysis, it was revealed that inclusions of intermetallic compounds Mg5Si6, Al17(FeMn)Si2, and Al3(CuNi)2 are formed at melt cooling rates of 102 and 105 K/s. A mechanism of the formation of a layered microstructure of an eutectic alloy is proposed. An explanation for the formation of X-ray amorphous nanosized particles in the foil layer adjacent to the mold is given.

The structural and phase state of the surface layers of Al, Al-Si, and Al-Si-Cu-Mg alloys doped with zirconium atoms under the influence of compression plasma flows is studied. It is established that metastable compounds Al3Zr with the crystal structure L12 and (Al, Si)3Zr with the structure D022 are formed in the doped layers of aluminum and silumins, respectively. It is shown that doping of the studied alloys with zirconium makes it possible to increase the microhardness of the surface layer by 1.4–3 times. A study of the thermal stability of the structural and phase state of the doped layers at 550°C showed that, as a result of aluminum annealing, the Al3Zr phase with the L12 structure transforms into the Al3Zr compound with the D023 structure, and in the alloys of the Al–Si system, the decomposition of (Al,Si)3Zr and the formation of ZrSi2 occur. It is noted that the synthesized surface layer has increased temperature strength.

The article presents a technique for obtaining advanced layered radio-absorbing materials based on powdered charcoal. The technique includes the following technologies: incorporation of the electrolyte aqueous solution into the material particles pores and adhesive pressing. The developed technique is more manufacturable compared to its analogs. Materials obtained in accordance with this technique are characterized by flexibility, as well as lower cost compared to other carbon-containing radio-absorbing materials. The experimental characteristics of electromagnetic radiation reflection and transmission coefficients in the frequency range 2.0–17.0 GHz of the materials obtained in accordance with the developed technique are described. The results of the comparative analysis of these characteristics are provided. On the basis of these results, it is determined that the average values of electromagnetic radiation reflection coefficient in the specified frequency range of the materials based on powdered nonactivated wood charcoal, powdered activated wood charcoal, and powdered activated coconut charcoal are –4.5, –8.5, and –9.0 dB (when these materials fixed on metal reflectors). The average values of their electromagnetic radiation transmission coefficient are –11.5, –20.0, and –15.5 dB respectively. The investigated materials seem to be promising for use in order to protect electronic equipment from external electromagnetic interference.

Composite polylactide materials based on hydrated calcium phosphates (amorphized hydroxyapatite and brushite) promising for 3D printing of osteoplastic biomaterials are obtained by an extrusion method. The formation of coatings containing amorphized hydroxyapatite promotes 1.5- to 3.5-fold strengthening of three-dimensional models based on such composite materials and leads to hydrophilization of their surface.

The magnetic properties of the soft magnetic composites based on an ABC100.30 iron powder with a phosphorus oxide insulating coating of different thicknesses have been studied. It has been found that the composites with a trilayer particle coating exhibit the minimum of magnetic hysteresis value. This causes a decrease in the magnetization reversal loss in the materials with a trilayer insulating coating by an order of magnitude as compared with the loss in the composites based on the powders with a single-layer particle coating. The developed materials with a permeability of μ = 100–150 and an induction of up to 1.8 T are promising for use in various electrical devices operating in the frequency range of up to 1 MHz.

The article presents a study of acrylic dispersions modified with multilayer carbon nanotubes to create impregnating compositions of pyramidal radio absorbing materials based on foamed polyurethane. The effect of the type of multilayer carbon nanotubes on the stability of acrylic dispersions is studied. It is established that less than 0.5% of the incident radiation is able to pass through a sample with Taunit-MD MWCNTs and aging of acrylic dispersion for 5 days; at the same time, the material has the best absorption indicators—the transmission coefficient does not exceed 0.001%.

This article describes features of technical embodiment and exemplifies practical application of the technology of thermohydrochemical treatment (THCT) for surface hardening of steel, hard alloy, and diamond metal processing tools. The THCT method comprises (1) hydrochemical treatment of tools in boiling hydrosols of ceramic materials for deposition of solid lubricating coatings and (2) subsequent heating to 130‒1050°C. After THCT, the operational resistance of steel tools increases by 1.4–8 times, the resistance of hard alloy tools increases by 1.3–3.6 times, and the resistance of diamond tools increases by 1.6–3.3 times in comparison with conventional hardening.

This article describes the experimental results of microstructure and phase composition of Bi32I-n41Sn27 alloy obtained by ultrarapid solidification from melt at the melt cooling rate of 105 K/s. Rapidly solidified Bi32In41Sn27 alloy is composed of the ε phase (BiIn) and γ phase (Sn4In) having a dispersed structure. The average value of chords dγ of random secants located on the cross sections of the γ phase and the average specific surface area of the interphase boundary Sε–γ formed by the ε and γ phases depend on holding time t of the foil at ambient temperature; their dependences are described by the equations dγ = 0.58 + 0.29lnt and Sε–γ = 2.9 – 0.43lnt. Microhardness Hμ of the Bi32In41Sn27 alloy foil monotonically increases with holding time at ambient temperature and reaches saturation. Subsequent isothermal annealing at 60°C leads to Hμ equaling the microhardness of bulk specimen obtained at average cooling rates of 102 K/s. The chemical compositions of the foil in the layer adjacent to the surface of the solidification unit and in the layer contacting the environment agree in the range of measurement error. The alloy foil has a microcrystalline structure. In the alloy foils, the sharp texture (0001) of the γ phase and the weak binary texture (211) + (112) of the ε phase are generated, which do not change upon annealing at 60°C for 2 h. The Bi32In41Sn27 alloy foil can be used as a solder alloy without harmful components (lead, cadmium, and others).

Brushite coatings were obtained on titanium by the method of electrochemical deposition from Ca(NO3)2/NH4H2PO4 electrolyte at Ca/P = 1.67, pH 4, and a constant voltage of 15 V or a current density of 20 mA/cm2 for 20 min. In a medium of 0.01–0.10% polyvinyl alcohol at a constant voltage of 15 V, single-phase brushite or monetite coatings are deposited. The addition of 0.01–0.10% polyvinyl alcohol to the electrolyte during deposition at a constant current density of 20 mA/cm2 leads to the formation of composite calcium phosphate coatings containing brushite, calcium hydroxide, and calcium phosphate of the apatite structure. The bioactivity of calcium phosphate coatings was confirmed by the formation of apatites during their soaking in the Simulated Body Fluid (SBF). Amorphized apatite that formed on brushite coatings during soaking for 2 weeks in SBF crystallizes into β-tricalcium phosphate after heat treatment. The apatite that formed on the composite coating in the SBF crystallizes into a composition of hydroxyapatite and β-tricalcium phosphate. The resulting bioactive calcium phosphate coatings can be used as biocoatings to enhance osseointegration of titanium implants.

This article describes study of the microstructure and texture of aluminum alloy foils containing 0.25–2.0 wt % Bi and manufactured by high speed solidification. The cooling rate of the melt is at least 105 K/s. Aluminum texture (111) is generated in the foils. The average chord of cross sections of bismuth spherical precipitates does not exceed 0.5 μm. The size of dispersed bismuth particles increases and their number per unit volume of aluminum matrix decreases with increase in the distance to the foil surface. The specific surface area of interface boundary at first increases and then decreases upon movement of solidification front. The alloy foils are dissolved in water at ambient temperature, forming hydrogen bubbles and amorphous powder of Al2O3⋅5(H2O) and Al2O3⋅3(H2O) aluminum hydrides.

Changes in the structure, phase composition, and mechanical properties of Ti–C60–Ti films implanted with B+ ions (E = 80 keV, D = 1 × 1016 ions/cm2) after annealing in vacuum at a temperature of 570 K (3 h) are studied by atomic force microscopy, X-ray diffraction, and nanoindentation. The films are synthesized by resistive evaporation in vacuum. Titanium and C60 fullerite layers are sequentially deposited onto a substrate of oxidized single crystal silicon. It is established that intense diffusion of titanium into the fullerite layer occurs during the condensation of the fullerite layer (h = 250 nm) on the underlying titanium layer (h = 120 nm) and then the titanium layer (h = 150 nm) on the fullerite layer. Implantation of titanium–fullerite–titanium films with boron ions leads to mixing of titanium and fullerite layers, while the size of structural components increases from 40 nm to 80 nm compared to nonimplanted films. Auger electron spectroscopy reveals that ion implantation gives rise to an increase in the atomic fraction of oxygen in the films and the formation of a new phase of TixOyC60, which leads to an increase in the nanohardness of the mixed layers. The implanted Ti–C60–Ti films are annealed in vacuum at T = 570 K for t = 3 h. Thermal annealing gives rise to recrystallization of the fullerite phase and intense growth of a new phase of TixOyC60 with improved mechanical properties.

By firing polyurethane foam templates (STR brand, 12 pores per cm, China) with a porosity of ~65% at 1200°C, an open-pore calcium phosphate foam ceramic was obtained using a highly concentrated suspension based on synthetic hydroxyapatite heat-treated at 800°C, monocalcium phosphate monohydrate, and 0.8% polyvinyl alcohol. The resulting calcium phosphate foam ceramic after modification in SBF (simulated body fluid) solution concentrated by 5 times (SBF×5) consisted of β-tricalcium phosphate, β-calcium pyrophosphate, and biomimetic apatite and had a porosity of 53–59% and a static strength of ~0.05 MPa. The formed biomimetic apatite consisting of amorphous calcium phosphate Ca9(PO4)6 and apatite tricalcium phosphate Ca9HPO4(PO4)5OH crystallizes into β-tricalcium phosphate at 1200°C. Calcium phosphate foam ceramic modified with biomimetic apatite, after soaking in 5% hydroxyapatite gel and SBF×5, simulating a bone defect in vitro, in parallel with the formation of biomimetic apatite, is partially destroyed, which confirms its high bioactivity and resorbability.

The phase composition, microstructure, and mechanical properties of rapidly solidified foils of Sn–Zn eutectic alloys doped with antimony are studied. The alloy foils have a uniform distribution of components. The rapidly solidified eutectic consists of dispersed precipitates of a zinc phase distributed in a tin matrix; antimony forms an intermetallic compound with zinc. The rapidly solidified eutectic alloy doped with antimony has a microcrystalline structure, and no texture is observed. Twins are formed in eutectic alloys with antimony when grain sizes are small. The microhardness of the foils increases with an increase in concentration of antimony. The supersaturated solid solution decomposes at room temperature during holding of rapidly solidified foils. The annealing of foils leads to a decrease in microhardness and growth of the microstructure.

The effects of high-energy compression plasma flows on the structure, elemental composition, and phase state of Al–44 at % Si hypereutectic silumin alloy have been investigated. Using scanning electron and optical microscopy it was found that a decrease in grain size of both primary silicon particles and Al–Si eutectic components occurs with an increase in absorbed energy density of compression plasma flows. The primary silicon crystals were dispersed down to 300 nm as a result of the high cooling rate of the melted layer after its homogenization by means of hydrodynamic mixing. It was found that, with the increase in the absorbed energy density, homogenization of the elemental composition in the modified layer occurs owing to an increase in the lifetime of the melted state and a more efficient mixing process.

Silumins are advantageous antifriction alloys to produce friction units. However, owing to their low hardness and strength, there is a call for developing modifying and strengthening additives for them. Here, we prepare aluminosilicate–nickel (AS/Ni) composites by mechanochemical synthesis and propose them as the additives. Using Fourier transform infrared spectroscopy and X-ray diffraction, we investigate the structural changes in (1) powder mixtures of natural aluminosilicates and nickel subjected to high-energy mechanical processing in a planetary ball mill and (2) silumin–potassium tetrafluoroborate (KBF4) and silumin–KBF4–AS/Ni alloys prepared by hot pressing of the mechanically activated powders. Mechanical activation of the silumin–KBF4 powder mixture is shown to result in redistribution of silicon to form coarse primary silicon crystals in sintered material and a ~20% decrease in its microhardness. Mechanical activation of the aluminosilicates and nickel produces composite powders in which OH groups are removed and SiO2 framework units are formed. With this type of modifier used in sintering of silumin, the resulting alloy acquires a homogeneous finely dispersed structure with smaller eutectic particles and primary silicon grains, which improves the microhardness of alloy by a factor of 1.5.

The results of a study of the tribotechnical properties of solid lubricating coatings obtained on the VK6 hard alloy (94% WC + 6% Co) as a result of thermohydrochemical treatment (THCT) in a hydrosol based on silver graphite are presented. A multidimensional technological optimization of the composition of the medium and the temperature-time parameters of the THCT process was carried out according to the coefficient of friction of the obtained solid lubricating coatings. Using mathematical models, diagrams “process parameters–property” were constructed. Processing according to the optimal mode of THCT allows, in the absence of lubrication, to reduce the coefficient of friction of a hard-alloy surface by 3.5 times compared with an untreated one.

The paper presents results of studies of the optical and electromagnetic properties of the WO3/rGO electrochromic nanocomposite films obtained by mechanical spraying of a water-based dispersed solution with WO3/GO particles and heat treatment (annealing) at a temperature of 300°C in an inert argon atmosphere for 24 h. As a result, an electrically conductive phase of reduced graphene oxide rGO and crystalline WO3 was formed.

This work presents a study of the conditions and possibilities for the intercalation of hexafluorophosphate anions into CNT-based electrodes. For this, cathodes based on CNTs synthesized on different catalysts (Co–Mo)/(Al2O3–MgO) and (Fe–Co)/2.1Al2O3 were produced. As a result, electrode materials were obtained at various concentrations of CNT/graphite: CNT-4F, CNT-6, and CNT-6F. The resulting electrodes were studied by cyclic voltammetry (CVA) in an electrolyte of a dissolved LiPF 6 salt based on EC : DEC (ethylene carbonate : diethylene carbonate) solvents (in the ratio 1 : 1 : 1) with an admixture of 3% VC at a sweep speed of 4 mV/s. On the basis of the obtained CVA dependences, the specific charge/discharge capacity of the electrodes CNT-4F, CNT-6, and CNT-6F was determined. The largest specific charge/discharge capacity calculated per mass of CNTs was 292 and 164.22 (mA h)/g for CNT-4/graphite electrodes, and the minimum specific charge/discharge capacity was 41.67 and 1.5 (mA h)/g for CNT-4 electrodes without graphite, respectively. Also, the dependences of the average electrode utilization coefficient on the charge time at constant current on the cycle number at a charge of 300 s were obtained. For chronoamperograms of individual steps of the СNT-6F electrode, the values of lithium diffusion coefficients were calculated.

The results of the study of the parameters of the structure of the fast-solidificated foil of hypoeutectic, eutectic, and hypereutectic alloys of the Sn–Zn system containing 4.4, 8.8, and 15 wt % Zn are presented. The fast-solidificated foil consists of equiaxial zinc particles and a supersaturated solid solution of tin. The zinc particles are uniformly distributed in the foil, which is induced by the formation of a supercooled and supersaturated liquid solution and its subsequent spinodal decomposition. The tin- and zinc-enriched regions of the liquid solution transform to crystalline phase nuclei. The volume fraction of zinc particles, the mean chord of the random secants on the sections of the zinc particles, and the specific surface of the interphase boundary formed by zinc and tin increase with the increase in the concentration of zinc in the alloys under study. The foil of the Sn–Zn alloys has a microcrystalline structure, in which crystallographic texture of the grains is observed. The formation of the (100) texture of tin and (0001) texture of zinc is observed. The fast-solidificated foils of the alloys are in an unstable state, which leads to the decomposition of the supersaturated solid solution, dissolution of small particles, and growth of large particles. Annealing at 180°C for 22 h induces an increase in the mean chord of the sections of the zinc particles and volume of the zinc particles and a decrease in the specific surface of the interphase boundary.

Powders of calcium pyrophosphate Ca2P2O7 of γ- and β-modifications have been obtained using the thermal conversion of brushite CaHPO4⋅2H2O synthesized from phosphoric acid H3PO4 and calcium carbonate CaCO3 at a molar ratio P/Ca = 1.1. The resulting powders can be used to create various functional materials, including biocompatible and bioresorbable materials for the treatment of bone defects.

The heat effects at flow of direct current in nanomodified elastomers of two types (polyurethane and silicone compounds) were investigated. The multiwalled carbon nanotubes (MWCNT) synthesized over the (Co–Mo)/(Al2O3–MgO) and (Fe–Co)/2.1Al2O3 catalysts were used for nanomodification. The particle size analysis of MWCNT was carried out because the MWCNTs with various morphological parameters were synthesized over this type of catalysts. The composite manufactured on the basis of a silicone compound modified by 7 wt % of MWCNTs synthesized over the (Co–Mo)/(Al2O3–MgO) catalyst has the highest electrical conductivity (1.66 × 10–1 S cm–1), and the composite manufactured from the polyurethane compound modified by 1 wt % of MWCNT synthesized over the (Fe–Co)/2.1Al2O3 catalyst has the lowest electrical conductivity (6 × 10–10 S cm–1). Variations in heat dissipations for various types of elastomers modified by MWCNT were detected by using the noncontact method of measuring of temperature field on the surface of samples. The manner of stabilized heat dissipation which is natural for the materials with a positive temperature coefficient of resistance was found. The highest intensity of heat dissipations combined with uniform distribution of the temperature field was observed for the samples manufactured on the basis of a silicone compound containing 7 wt % of the MWCNTs synthesized over the (Fe–Co)/2.1Al2O3 catalyst. The maximum heating temperature for the sample operating under the voltage of 6 V of direct current was 102°C. Nonuniformity of heat dissipations is specific to almost all samples manufactured on the basis of the polyurethane compound. In this case, the samples based on the silicone compound demonstrate uniform heating at any level of filling by the MWCNTs. As a part of the study, a honey-combed sample was obtained, which, under the voltage of 6 V of direct current, was heated to 100°C and had a uniform distribution of the temperature field.