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PtCu/C electrocatalysts with bimetallic PtCu nanoparticles were synthesized by successive chemical reduction of Cu2+ and Pt(IV) in a carbon suspension prepared based on an aqueous ethylene glycol solution. The atomic structure of as-prepared PtCu nanoparticles and nanoparticles subjected to thermal treatment at 350°C was examined using PtL 3 and CuK EXAFS spectra, transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). The results of joint analysis of TEM microphotographs, XRD profiles, and EXAFS spectra suggest that the synthesized electrocatalysts contain PtCu nanoparticles with a Cu core–Pt shell structure and copper oxides Cu2O and CuO. Thermal treatment of electrocatalysts at 350°C results in partial reduction of copper oxides and fusion of bimetallic nanoparticles with the formation of both homogeneous and ordered PtCu solid solutions.

The temperature dependences of the specific heat, thermal conductivity, coefficient of thermal expansion (CTE), and transport coefficients (electrical conductivity and thermoelectric power) of copper selenide are experimentally and theoretically investigated in the temperature range of 300–873 K. The calculation results correlate with the experimental data up to a temperature of ~773 K. The maximum thermoelectric figure of merit of nanostructured copper selenide is ZT ~ 1.8. The correlation dependence between ZT and the thermal conductivity within the entire temperature range under consideration is shown.

The effect of synthesis conditions on the structure and thermoelectric properties of zinc-antimonide- based materials is investigated. The effects of Zn excess, the modes of spark plasma sintering, and In doping on the phase composition and the thermal stability of the properties of the obtained material are considered. The material is prepared by the method of the direct alloying of components and spark plasma sintering. It is shown that, at certain modes of spark plasma sintering, the introduction of an excess amount of Zn and In doping make it possible to obtain β-Zn4Sb3 with the thermoelectric efficiency ZT ≈ 1.47 at a temperature of 720 K, which shows the stability of characteristics under the performed tests.

The influence of severe plastic deformation on the structural-phase state of grain boundaries in a Ti–4Al–2V (commercial PT3V grade) pseudo-alpha-titanium alloy has been studied. It is established that increase in the strength, plasticity, and corrosion resistance of this alloy is related to the formation of an ultrafine- grained structure. In particular, it is shown that an increase in the resistance to hot-salt intergranular corrosion is due to diffusion-controlled redistribution of aluminum and vanadium atoms at the grain boundaries of titanium formed during thermal severe plastic deformation.

The operation-mode stability and the catalytic activity in electrode reactions are the most important properties of electrocatalysts that determine the possibility of using them in fuel cells. The negative linear correlations between stability and catalytic activity of a series of Pt/C and Pt–Cu/C materials in the oxygen electroreduction reaction are revealed and studied. A method of selecting electrocatalysts with the optimal combination of activity and stability is proposed. The Cu@Pt/C catalysts containing bimetallic nanoparticles with the core–shell architecture which demonstrate the anomalously high combination of activity and stability are synthesized.

The structure of the optical centers of Eu3+ ions in tetragonal (ZrO2)1–x–y(Y2O3)x(Eu2O3)y (х = 2.7–3.6; y = 0.1) and cubic (ZrO2)1–x–y(Y2O3)x(Eu2O3)y (х = 8–38; y = 0.1–0.5) crystals of solid solutions on the basis of zirconium dioxide is studied using the methods of optical and Raman-scattering spectroscopy. Characteristic optical centers of Eu3+ ions with different crystalline environments are revealed in the above compounds.

The effect of dysprosium added in the amounts such that it does not form an individual phase in equilibrium with solid magnesium on the decomposition of the supersaturated magnesium solid solution in Mg–Sm alloys is studied. The presence of dysprosium in Mg–Sm alloys is found to retard the decomposition of the supersaturated magnesium solid solution and to increase the hardening effect upon aging. When these alloys are aged, dysprosium is partly retained in the magnesium solid solution and partly enters into the compositions of the phases that form during the decomposition of the solid solution and are characteristic of Mg–Sm alloys.

The interrelationship between the structure, phase composition, and transport characteristics of solid electrolytes based on ZrO2 has been studied as dependent on the content of stabilizing Y2O3 additive. It is established that twin boundaries do not lead to the appearance of additional mechanism of ionic conductivity acceleration in ZrO2–Y2O3 crystals. The maximum conductivity has been observed in ZrO2–(8–10) mol % Y2O3 crystals containing a t” phase, in which oxygen atoms are displaced from high-symmetry positions characteristic of the cubic phase.

Using the methods of powder X-ray diffraction, transmission electron microscopy, and EXAFS spectroscopy, the phase behavior of bimetallic Pt–Cu nanoparticles with different architecture that are deposited on a highly disperse carbon carrier has been investigated during their thermal treatment in inert atmosphere. It is established that Pt–Cu nanoparticles with a Cu-core–Pt-shell structure rearrange into nanoparticles with a Pt–Cu solid-solution structure in the temperature range from 280 to 300°C. This transformation is accompanied by a sharp change in the unit-cell parameter. Such a change in the crystal lattice parameter does not occur during the thermal treatment of material with similar composition containing Pt–Cu nanoparticles with a solid-solution structure. The results can be used in elucidating the structure of Pt–M/C materials with different nanoparticle architectures.

The shape memory effect (SME) in alloys with a thermoelastic martensite transition opens unique opportunities for the creation of miniature mechanical devices. The SME has been studied in layered composite microstructures consisting of a Ti2NiCu alloy and platinum. It occurs upon a decrease in the active layer thickness at least to 80 nm. Some physical and technological restrictions on the minimum size of a material with SME are discussed.

Ground chips of as-cast Al-10 wt.% Zr alloy were subjected to mechanical alloying (MA) with 5 vol.% of nanodiamond addition in a high energy planetary ball-mill. The aim of this work was to investigate the microstructure, phase transformation and mechanical properties of the material both after MA and after subsequent annealing. Optical and transmission electron microscopes were used for morphological and microstructural analysis. The effect of milling time on powder microhardness, Al lattice parameter, lattice microstrain and crystallite size was determined. It was shown that mechanical alloying of as-cast Al-10wt.%Zr alloy during 20 h leads to a complete dissolution of the primary tetragonal Al3Zr crystals in aluminum. At the same time, the powder microhardness increases to 370 HV. Metastable cubic Al3Zr phase nanoparticles precipitate from the Al solution due to its decomposition after annealing, however, the Al solid solution remains supersaturated and nanocrystalline. Compression tests at room temperature and at 300 °C showed that the strength values of the hot-pressed samples reach 822 MPa and 344 MPa, respectively.

The influence of the structural-phase state of grain boundaries in a Ti4Al2V (commercial PT3V grade) pseudo-alpha-titanium alloy on its susceptibility to hot-salt intergranular corrosion (IGC) has been studied. It is established that IGC-tested alloy samples exhibit corrosion-induced defects of two types. More extended defects of the first type occur at the V-rich boundaries of coarse grains, while short defects of the second type reside at the grain boundaries with composition close to that of the grain body. The existence of the two types of IGC defects is explained by the classical theory of galvanic microcouples (microcells), according to which the IGC intensity is proportional to the difference of corrosion-active impurity concentrations between the grain boundary and body.

For the first time crystals of the (ZrO 2 ) 1− x − y (Sc 2 O 3 ) x (Y 2 O 3 ) y solid solutions ( x =0.08–0.11; y =0.01–0.02) have been grown by directional melt crystallization. We have determined the range of melt compositions for which growth from the melt produces of the (ZrO 2 ) 1 − x − y (Sc 2 O 3 ) x (Y 2 O 3 ) y solid solution single crystals. The single-phase optically transparent single crystals following composition were grown: (ZrO 2 ) 0.9 (Sc 2 O 3 ) 0.08 (Y 2 O 3 ) 0.02 ; (ZrO 2 ) 0.89 (Sc 2 O 3 ) 0.09 (Y 2 O 3 ) 0.02 ; (ZrO 2 ) 0.89 (Sc 2 O 3 ) 0.10 (Y 2 O 3 ) 0.01 ; (ZrO 2 ) 0.88 (Sc 2 O 3 ) 0.10 (Y 2 O 3 ) 0.02 . Comprehensive study of the crystal structure by using XRD, transmission electron microscopy, and Raman spectroscopy revealed that the all single crystals, which is identified by XRD data as cubic one, in fact have t″ tetragonal structure, which forms by small displacement of oxygen ions along the c -axis. Data on the phase stability of the crystals during mechanical crushing were obtained. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. It is established that (ZrO 2 ) 0.89 (Sc 2 O 3 ) 0.10 (Y 2 O 3 ) 0.01 crystals have the highest conductivity (0.168 S/cm at 1173 K).

In this work, mathematical modeling was used to optimize the geometry of the composite mold for developing the technology of equal−channel angular pressing with three channels for thermoelectric materials. To obtain the maximum degree of deformation in this work, we used a three−channel scheme. Taking into consideration the material characteristics (low resistance to tensile stresses), we proposed a tapering profile (along the length) of the third channel. To analyze the plastic flow in the proposed scheme of equal−channel angular pressing with three channels, we performed mathematical modeling of plastic flow, stress and deformation rates along the rod, deformation homogeneity along the cross−section and absence of stagnant zones in the extruder. The methodical approach is based on the combined use of the elastic and plastic solid state approximations according to the fundamentals of the elasticity and plasticity theory. Critical points are identified having the maximum stored energy accumulation without discontinuity of the material. Calculation of the flow velocity in planes perpendicular and parallel to the deformation axis showed a slight difference in the flow rate of the material for the section plane parallel to the deformation axis. This produces a bend with a large curvature radius but does not cause cracking of the material. Calculation of deformations along the flow axis allowed us to detect deformation inhomogeneity. This resulted in the appearance of small tensile stresses in the longitudinal section of the third channel. We show that the plastic deformation inhomogeneity revealed by modeling can be eliminated by using an equipment design with a greater output channel length. Mathematical modeling shows the suitability of the suggested unconventional design of equal−channel angular pressing equipment for bismuth chalcogenide base solid solutions.

The formation of nanoparticles in СZn-Si(100) implanted with 64Zn+ ions using a dose of 5 × 1016 cm–2 and an energy of 50 keV at room temperature with subsequent thermal processing in oxygen at temperatures ranging from 400 to 900°C is studied. The surface topology is investigated with scanning electron (in the secondary emission mode) and atomic force microscopes. The structure and composition of the near-surface silicon layer are examined using a high-resolution transmission electronic microscope fitted with a device for energy dispersive microanalysis. An amorphized near-surface Si layer up to 130 nm thick forms when zinc is implanted. Amorphous zinc nanoparticles with an average size of 4 nm are observed in this layer. A damaged silicon layer 50 nm thick also forms due to radiation defects. The metallic zinc phase is found in the sample after low-temperature annealing in the range of 400–600°C. When the annealing temperature is raised to 700°C, zinc oxide ZnO phase can form in the near-surface layer. The complex ZnO · Zn2SiO4 phase presumably emerges at temperatures of 800°C or higher, and zinc-containing nanoparticles with lateral sizes of 20–50 nm form on the sample’s surface.

We have studied the influence of the yttrium oxide (Y2O3) dopant (1 and 2 mol %) on the phase composition, structure, and electrical properties of ZrO2–9 mol % Sc2O3 solid solution. Stabilization of ZrO2 jointly with 9 mol % Sc2O3 and 2 mol % Y2O3 is shown to allow the acquisition of high phase stability transparent homogeneous crystals with a cubic structure. Their mechanical grinding is established to cause no change in the phase composition of these crystals, whereas the powders retain the initial fluorine structure. The powders preserved the original structure of the fluorite crystals. All the probed crystals reveal high microhardness and low fracture toughness. Increasing the Y2O3 concentration in the crystals led to a reduction of the maximum loads on the indenter, which the sample withstood without cracking. As is shown, the specific conductivity exhibits nonmonotonic behavior depending on the Y2O3 concentration in the crystals. Increasing the Y2O3 content to 2 mol % in the solid electrolyte reduces the conductivity of the crystals in the entire temperature range that is attributed to a decrease in the carrier mobility due to the increasing ion radius of the stabilizing ion.

Mo/Al/Mo/Au metallization scheme as an ohmic contact to undoped AlGaN/GaN heterostructures was investigated. The optimal thicknesses of the metal layers were determined: Mo (10 nm)/Al (60 nm)/ Mo (50 nm)/Au (50 nm). The specific contact resistance of the fabricated ohmic contact is 4.7 × 10–7 Ohm cm2 (0.14 Ohm mm). The microstructure of the contact after annealing was investigated using scanning and transmission electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy. It is shown that a noticeable alloying of metallization into semiconductor upon annealing does not occur, but strong mixing of metals takes place. X-ray diffraction analysis demonstrated the presence of interfacial compounds, namely, Al2Au, Al3 + x Mo1–x , AlMo3, Al12Mo, GaMo3 and GaAu2. Investigations of the phase composition of films depending on the thickness ratio of the metallization layers have shown that the formation of Al2Au phase has a negative effect on the contact surface morphology, and the formation of GaMo3, Al x Moy phases likely plays the most important role in the ohmic contact formation, which was also confirmed by the method of energy-dispersive analysis.

The influence of homogenisation regimes on precipitations of fine Mn-bearing dispersoids, recrystallisation kinetics, grain structure, mechanical properties and superplasticity of cold worked sheets of Al-3Mg alloys with Mn, Cr and Zr is studied. Precipitates of coherent compact and plate-like particles of Mn-bearing phase are found after homogenisation annealing. Activation parameters of the low-temperature internal friction, internal friction solute grain boundaries peak and dislocation nature thermally activated relaxation peak in the samples treated by different regimes are compared. High-temperature homogenisation at 460 °C provides a higher volume fraction and finer particles of Mn-containing phases after thermomechanical processing compared to low temperature treatment at 380 °C. Consequently, finer grains and higher superplasticity indicators are achieved in a recrystallised state. Polygonisation is observed during heating of the cold worked samples pre-homogenised at 380 °C: recrystallisation temperature is increased and mechanical strength at room temperature is improved. Keywords: Aluminium alloys, Precipitations, Recrystallisation, Internal friction, Superplasticity

The data presented in this article are related to the research article entitled “Phase stability and transport characteristics of (ZrO(2))(1-x)(Sc(2)O(3))(x)(СeO(2))(y) and (ZrO(2))(1-x-y-z)(Sc(2)O(3))(x)(СeO(2))(y)(Y(2)O(3))(z) solid solution crystals” https://www.sciencedirect.com/science/article/pii/S2352340917302329 [1]. It contains data on densities and microhardness of the as-grown crystals. The data on the specific conductivity of the as-grown and annealing at 1000 °С for 400 h ScCeSZ and ScCeYSZ crystals in the temperature range 623–1173 K is also included in this article. The article describes also the growth of the (ZrO(2))(1-x)(Sc(2)O(3))(x)(СeO(2))(y) and (ZrO(2))(1-x-y-z)(Sc(2)O(3))(x)(СeO(2))(y)(Y(2)O(3))(z) solid solution crystals using directional melt crystallization in a cold crucible.

The current study compares Al-Mn and Al-Mn-Mg alloys’ precipitation behavior in a temperature range of 350–450 °C. Mn-bearing nanodispersoids of the quasicrystalline-structured I-phase precipitate during the decomposition of supersaturated Al-based solid solution in both alloys. In the binary Al-Mn alloy, quasicrystalline-structured dispersoids precipitate only in the grain boundaries. The Mg addition does not change the dispersoids’ composition but significantly accelerates the precipitation kinetics. The Mg addition provides the precipitation of high-density distributed I-phase nanodispersoids in the body of the grains. The annealing temperature increase results in the I-phase transformation to a cubic α-phase, with both phases coexisting in the alloy structure.

Low plasticity is a key drawback limiting the widespread use of bulk metallic glasses. Although heat treatment and thermo-mechanical processing techniques are not applied to metallic glasses (only to supercooled liquids), since heating leads to embrittlement either due to structural relaxation or thermal crystallization, in this paper, we demonstrate a strong positive effect of cold rolling and subsequent thermal annealing below the glass-transition temperature on room-temperature mechanical properties of a Zr62·5Cu22·5Fe5Al10 glassy alloy. As a result we observed mechanical softening and appearance of tensile ductility (up to 1.5%) in bulk samples and an increase in hardness by up to 25% in ribbon samples yet retaining good bending plasticity. We believe that the proposed method can be applied to a number of metallic glasses.

The issues of laser treatment of nanostructured partially stabilized crystals of zirconium dioxide are studied in the article. The phenomena of formation of the topography of the surface of crystals after treatment by focused radiation of a repetitively pulsed laser at a wavelength of 1.06 μm are investigated. Structural changes in the surface layer have been studied by X-ray phase analysis. The formation of a golden film on the surface of the treated crystal and ceramic sample of the same chemical composition and the effect of reducing the coefficient of friction have been established. The tribological properties of PSZ crystals are investigated during friction without lubrication in the sliding mode.

Magnesium-base alloys attract a great attention as light structural materials, where economy of weight is of great importance. According to the last investigations, the highest strength properties of these alloys, can be obtained, when they contain some of the rare-earth metals. All of them belong to the yttrium group. Existence of the rare-earth metals in magnesium alloys enable to form in their structures small hard particles, which increase significantly strength of the alloys. The hard particles appear after the special heat treatments and should have the certain measurements and amounts. In this article the main results of some investigations are described, where the best conditions for the heat treatments of the magnesium alloys with high strength were established. The highest strength in the alloys was observed, when the hard particles were nano-scale in them with certain disposition in the structure.

In this work samples of Fe-Mn alloys were subjected to equal-channel angular pressing (ECAP) in order to study the effect of the resulting microstructure on the mechanical properties, biodegradation rate, and biocompatibility in vitro of the alloys. The microstructure of the alloys was studied by scanning and transmission electron microscopy, as well as by X-ray diffraction analysis. Mechanical properties were studied by microhardness and tensile tests. It is shown that as a result of deformation by the ECAP method, a predominantly austenitic ultrafine-grained (UFG) structure is formed, shear bands up to 600 nm thick and nanosized twins up to 40 nm thick were observed. The release of α-Mn particles in the ECAP process was revealed. Due to the structure refinement and twinning during ECAP, the strength characteristics of Fe-Mn alloys were significantly increased compared to the corresponding alloys in the initial annealed state. An increase in the propensity to biodegradation of UFG alloys with their satisfactory hemocompatibility was observed.

Single crystals of solid electrolytes of the (ZrO2)1–x–y (Sc2O3) x (Y2O3) y (x = 0.035–0.11, y = 0‒0.02) system were grown by selective melt crystallization. Stabilization of ZrO2 only with Sc2O3 in the concentration range 9–11 mol % Sc2O3 did not afford crystals with a cubic structure, and only the introduction of additional Y2O3 stabilizers afforded uniform transparent single-phase cubic crystals. All the crystals under study had high microhardness, but low crack resistance. The ion conductivity of crystals with 6 and 9 mol % Sc2O3 (6ScZr and 9ScZr, respectively) is comparable to that of 8 mol % Y2O3-stabilized ZrO2 (8YSZ), which is the most suitable electrolyte in the ZrO2–Y2O3 binary system. The specific conductivity of crystals containing 8–10 mol % Sc2O3 and 1–2 mol % Y2O3 exceeds that of other materials including 8YSZ. The maximum conductivity in the given range of compositions is inherent in the cubic phase with 10 mol % Sc2O3 and 1 mol % Y2O3 (10Sc1YZr).

Investigation of partially stabilized zirconium dioxide crystals via transmission electron microscopy has revealed a developed twin structure therein. The following compositions of the above crystals have been selected for this study: 97.2 mol % ZrO2–1.0 mol % Y2O3–1.8 mol % Yb2O3; 97.2 mol % ZrO2–2.0 mol % Y2O3–0.8 mol % Yb2O3; 97.2 mol % ZrO2–2.5 mol % Y2O3–0.3 mol % Yb2O3; and 96.3 mol % ZrO2–3.4 mol % Y2O3–0.3 mol % Yb2O3. X-ray diffraction analysis of these crystals indicate the presence of transformable (t) and nontransformable (t') tetragonal phases. Optical spectroscopy measurements of ZrO2–Y2O3–Yb2O3 crystals with tetragonal and cubic structures have highlighted in Yb3+-doped zirconium dioxide samples the formation of the optical centers of the Yb3+ ions is observed, whose crystal surrounding is similar to those in cubic zirconium dioxide crystals.

The age-hardenable Mg-4.7%Y-4.6%Gd-0.3%Zr (wt%) alloy has been studied after high pressure torsion (HPT) at room temperature, 200 °C and 300 °C. The formation of partially nanocrystalline structure upon HPT results in substantial strengthening relative to the undeformed state of the alloy. The research showed that the strength of the HPT processed alloy could be further improved by aging.

Crystals of (ZrO 2 ) 1− x (Sc 2 O 3 ) x solid solutions with x =0.035, 0.06, 0.09 and 0.11 have been grown for the first time using the directional crystallization technique. Analysis of the scandium distribution along the crystal showed that the composition of all specimens is homogeneous, and the Sc 2 O 3 concentration is almost identical to its content in the charge. All specimens exhibit a little decline in the scandium concentration along the crystal, this indicating that the effective distribution coefficient Sc is slightly greater than 1. The structure of as-grown crystals has been studied as a function of the Sc 2 O 3 stabilising oxide concentration by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. Crystals containing 3.5 mol% Sc 2 O 3 are a mixture of the monoclinic and tetragonal phases, the crystals containing 6 mol% Sc 2 O 3 have a tetragonal structure, those with 9 mol% Sc 2 O 3 have the tetragonal phase with inclusions of the rhombohedral one and the specimens with 11 mol% Sc 2 O 3 represent the rhombohedral phase with inclusions of the cubic phase. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. The conductivity of the scandia stabilized crystals, in spite of their inhomogeneity, presence of stresses and low fracture toughness, is comparable with that of the yttria stabilized zirconia crystals.

The formation of nanoparticles containing zinc in Si(001) substrates by the implantation of 64Zn+ ions and subsequent annealing in dry oxygen at 800 and 1000°C for 1 h is studied. The structure of the samples is studied by high-resolution transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. 20-nm zinc nanoparticles located at a depth of about 50 nm are revealed in the as-implanted sample. 10–20-nm pores are observed in the surface layer. Annealing leads to oxidation of the Zn nanoparticles to the Zn2SiO4 state. It is shown that the oxidation of Zn nanoparticles begins on their surface and at an annealing temperature of 800°C results in the formation of nanoparticles with the “соre–shell” structure. The X-ray diffraction technique shows simultaneously two Zn and Zn2SiO4 phases. ZnO nanoparticles are not formed under the given implantation and annealing conditions.

The up-conversion luminescence of Er3+ from the 2 H 11/2, 4 S 3/2, and 4 F 9/2 levels in nanocrystals of Y0.95(1‒x)Yb0.95x Er0.05PO4 (x = 0, 0.3, 0.5, 0.7, 1) orthophosphates activated with Er3+ ions has been studied under the excitation of Yb3+ ions to the 2 F 5/2 level by 972-nm cw laser radiation. Broadband radiation in the wavelength range of 370–900 nm has been observed at certain power densities of exciting laser radiation; this broadband radiation is absent in the case of excitation of the powders under study by pulsed laser radiation with a wavelength of 972 nm at a pulse repetition frequency of 10 Hz and a duration of a pulse of 15 ns. Experimental data indicating that this radiation is thermal in nature have been presented.

The sequential chemical reduction of metals (copper or silver) and platinum was used to prepare M@Pt/C electrocatalysts that contain a high content of platinum on the surface of bimetallic nanoparticles. The compositions, microstructures and electrochemical behaviors of these electrocatalysts were studied using X-ray diffraction, thermogravimetry, X-ray fluorescence analysis, TEM and cyclic voltammetry. Depending on the composition and mode of synthesis, the obtained electrocatalysts have electrochemically active surface areas ranging from 35 to 61 m2 g−1 (Pt). The presence of nanoparticles with a core-shell structure was directly confirmed for Cu0.9Pt0.1@Pt/C sample. Copper-containing electrocatalysts exhibited better stability during voltammetric cycling compared to a similar composition of commercial Pt/C electrocatalyst and Ag0.9Pt0.1@Pt/C systems, but one of Ag0.9Pt0.1@Pt/C electrocatalysts has shown the highest specific activity in ORR.

Pt/C catalysts containing 10 to 20 wt % Pt have been prepared by chemical reduction of platinum from Pt(IV) solutions. The use of an intermediate hydroxide support (Fe(OH)2 or SiO2 · nH2O) in Pt/C synthesis has been shown to have a significant effect on the weight percentage, crystallite size, and electrochemically active surface area of Pt. We have established how the composition of the liquid-phase synthesis atmosphere (air, Ar, or CO) influences the structural characteristics of the Pt/C materials. The electrochemically active surface area of Pt in the synthesized catalysts ranges from 32 to 152 m2/g Pt.

The SIMOX commercial sample (Ibis corp.) was investigated by a high-resolution X-ray diffraction (HRXRD), a high-resolution transmission electron microscopy (HRTEM) and an Auger electron spectroscopy (AES) to determine its actual parameters (the thickness of the top Si and a continuous buried oxide layer (BOX), the crystalline quality of the top Si layer). Under used implantation conditions, the thickness of the top Si and BOX layers was 200 nm and 400 nm correspondingly. XRD intensity distribution near Si(0 0 4) reciprocal lattice point was investigated. According to the oscillation period of the diffraction reflection curve defined thickness of the overtop silicon layer (220 ± 2) nm. HRTEM determined the thickness of the oxide layer (360 nm) and revealed the presence of Si islands with a thickness of 30–40 nm and a length from 30 to 100 nm in the BOX layer nearby “BOX-Si substrate” interface. The Si islands are faceted by (1 1 1) and (0 0 1) faces. No defects were revealed in these islands. The signal from Si, which corresponds to the particles in an amorphous BOX matrix, was revealed by AES in the depth profiles. Amount of Si single crystal phase at the depth, where the particles are deposited, is about 10–20%.

The influence of treatment temperature and a carbon precursor on the formation of a Li4Ti5O12-based anodic material and its electrochemical characteristics as part of a lithium-ion battery have been investigated. It is demonstrated that the variation of annealing temperature and the addition of saccharose prior to final annealing allow for the variation of Li4Ti5O12 particle sizes. At annealing temperatures of 400–600°C, lithium titanate forms as part of an anatase titanium oxide composite. Thermogravimetry, Raman spectroscopy, and electrochemical testing results show that a preannealing of the sample at temperatures of no less than 400°C and the addition of saccharose with subsequent annealing in an inert atmosphere are required for the formation of a conducting carbon coating. The formation of the carbon coating facilitates the inclusion of the anatase phase into the charging and discharging processes, which significantly increases the electrochemical capacity of samples obtained at low annealing temperature. The highest electrochemical capacity values (140 mA h/g) of anodic Li4Ti5O12 samples were obtained only after annealing at 800°C. We note the unexpected formation of carbon nanotubes in samples with a final annealing temperatures of 600°C.

The property anisotropy in Bi2Se0.3Te2.7 alloy is analyzed by constructing index surfaces for the thermoelectric figure of merit and thermal expansion coefficient. Texture is an important factor forming the property anisotropy and technological applicability of an ingot for fabricating modules. The property anisotropy is analyzed based on studying the texture in ingots produced by the modified Bridgman method (thermoelectric plate growth in a flat cavity). Analysis of the texture shows that not only the crystallization rate, but also the crystallization cavity design is an important factor for the proposed crystallization method, affecting the formation of the thermoelectric-material structure. As the plate thickness is decreased by changing the heat removal conditions in a thin gap, a more perfect structure can be obtained.

(ZrO2)0.99-x(Sc2O3)x(Yb2O3)0.01 solid solutions crystals (x = 0.08–0.10) have been grown by directional crystallization of the melt in a cold crucible. Single-phase optically transparent single crystals were obtained only for the (ZrO2)0.90(Sc2O3)0.09(Yb2O3)0.01 composition. The phase composition, local structure and transport properties of the crystals have been studied using X-ray diffraction, Raman, optical and impedance spectroscopy. The dependence of the lattice parameters and the phase composition of (ZrO2)0.99-x(Sc2O3)x(Yb2O3)0.01 solid solutions on Sc2O3 content has been discussed. The (ZrO2)0.90(Sc2O3)0.09(Yb2O3)0.01 single-phase cubic single crystals had the maximum conductivity throughout the entire temperature range. It is shown that the high-temperature conductivity of the (ZrO2)0.90(Sc2O3)0.09(Yb2O3)0.01 single-phase cubic single crystals is close to the conductivity of the (ZrO2)0.90(Sc2O3)0.10 crystals. The results of studying the local structure of crystals by optical spectroscopy are presented.

This paper presents the results of studying the thermal stability of the grain structure, mechanical properties, and specific electrical resistivity of the Al-0.5 wt%Mg-xSc ultrafine-grained (UFG) alloys with varying scandium content (x = 0, 0.2, 0.3, 0.4, and 0.5 wt.%). The alloys were produced by induction casting and Equal-Channel Angular Pressing (ECAP). The alloys with Sc concentration above 0.3 wt% contained submicron Al3Sc primary particles, the amount of which increased with increasing Sc concentration. The decomposition kinetics of the Al–Sc solid solution in the UFG alloys was determined by the diffusion intensity along the dislocation cores in the lattice as well as at the grain boundaries. High thermal stability of the UFG structure in the alloys was ensured by ECAP at 225 оC whereas the recrystallization onset temperature was 375 оC. The UFG alloys exhibited high plasticity at the room and elevated temperatures and good combination of strength and electrical conductivity.

Effects of equal-channel angular pressing (ECAP) and rotary swaging (RS) with subsequent aging on the strength properties of Al-Mg2Si alloys with (Sc + Zr) and (Sc + Hf) additions were studied. The microstructure of deformed alloys was examined by optical and transmission electron microscopy (TEM). Mechanical properties were characterized by hardness measurements and tensile testing. It was found that the strength properties of Al-Mg2Si alloys were remarkably improved due to the structure refinement during cold deformation and the acceleration of the kinetics precipitation of the βʹ and βʹʹ phases during aging of deformed alloys. It is found an accelerated decomposition of the supersaturated aluminum-based solid solution in the presence of hafnium. Nearly the same values of hardness and tensile strength of Al-Mg2Si alloys with transition metals additions have been accounted for the more intense decomposition of the solid solution with hafnium has compensated by a larger amount of hardening phases (βʹʹ and βʹ) in alloys with zirconium. For all alloys the highest hardness was achieved after cold deformation and remained nearly the same after 2 h of aging.

The effect of co-doping an impurity on the transport parameters and cubic phase stabilization of ZrO2–Sc2O3-based solid solutions has been compared for Y2O3 and Yb2O3 dopants. Solid solution crystals of (ZrO2)1-x-y(Sc2O3)x(Yb2O3)y and (ZrO2)1-x-y(Sc2O3)x(Y2O3)y (x = 0.08–0.10, y = 0.01, 0.02) were grown by directional melt crystallization in a cold crucible. Co-doping of the (ZrO2)1-x(Sc2O3)x crystals (x = 0.08–0.10) with 2 mol% Y2O3 or Yb2O3 for all experimental compositions produced transparent homogeneous single crystals of the t” phase or the cubic phase. For co-doping of the scandia-stabilized zirconia crystals with 1 mol% Y2O3 or Yb2O3, the stabilization of the high-temperature phases depended on the Sc2O3 content in the solid solutions. For co-doping of the solid solutions with 1 mol% Y2O3 or Yb2O3, the conductivity of the crystals increased with the Sc2O3 concentration. For co-doping of the crystals with 2 mol% Y2O3 or Yb2O3, the conductivity decreased with the Sc2O3 concentration. At scandia concentrations of 9–10 mol%, the high-temperature conductivity of the crystals co-doped with ytterbia were higher compared to those with yttria co-doping. The (ZrO2)0.9(Sc2O3)0.09(Yb2O3)0.01 crystals had the highest conductivity over the entire experimental temperature range.

The work deals with application of laser radiation for creation of metamaterial – layered structural composite based on rapidly quenched TiNiCu thin ribbon. Structural properties of the composite were examined by transmission and scanning electron microscopy. Considerable two-way shape memory effect was achieved and studied.

The effects of equal-channel angular pressing (ECAP) and rotary swaging (RS) on the change in strength properties during aging at 170 ° C of Al-Mg-Si alloys doped with Sc, Zr and Hf additions was studied. The methods of measuring hardness, electrical resistivity, testing mechanical properties, light and transmission electron microscopy were used. The higher hardening effect compared to the initial state was found in the alloys after ECAP than after RS, whereas the strength properties (tensile strength and yield strength) were higher for alloys subjected to RS than ECAP. Al-Mg-Si alloys with the combined additives of scandium with zirconium and scandium with hafnium showed practically the same values of hardness and strength properties at tensile testing during aging. The reason is in the identical nature of the decomposition of the supersaturated solid solution. It is determined by the sequence of precipitation of the strengthening phase Mg2Si and (Sc1-x, Zrx) Al3 and (Sc1-x, Hfx) Al3 dispersoids which impede the movement of dislocations both in alloys after deformation and after aging.

This paper deals with formation, thermal stability and magnetic properties of Fe-Si-B-P-Mo amorphous and nanocrystalline alloys with minor Cu alloying. Amorphous melt-spun Fe84-85B8P3.5-4Mo1-2Cu0.5-1 (at%) alloy ribbons show good bending plasticity and crystallize through two stages with each onset temperature of about 673 and 813 K. Good soft magnetic properties were obtained in both amorphous and nanocrystalline (bcc-Fe + amorphous) states. The highest saturation magnetization and the lowest coercivity are ∼1.4 T and ∼4 A/m, respectively, for the amorphous phase and 1.8 T and 2.5 A/m, respectively, for the bcc-Fe + amorphous phases. The frequency dependence of permeability for nanocrystalline Fe84B8P3.5Si1.5Mo2Cu1 alloy remains nearly constant in a wide frequency range up to 65 kHz. Besides, the quality factor is higher over the whole frequency range up to 10 MHz for the nanocrystalline than for the amorphous alloy. These characteristics are promising for future engineering of high-frequency type soft magnetic materials.

(ZrO2) 0.97(Y2O3)0.03 and (ZrO 2)0.97(Gd2O3)0.03 solid solution crystals have been grown using directional melt crystallization in cold container. The structure and phase composition of the crystals have been studied using X-ray diffraction and transmission electron microscopy. The mechanical properties of the crystals e.g. microhardness and fracture toughness have been studied with microindentation. We show that the main hardening mechanism in the 3GdSZ and 3YSZ crystals is transformation hardening. No microhardness anisotropy has been observed in the crystals. The highest fracture toughness among the crystals has been obtained for the 3GdSZ crystals in the {100} plane.

The effect of introduction of 0.5 – 2 mol.% Yb2O3 additional doping oxide into ZrO2 – 10 mol.% Sc2O3 solid solutions on the phase composition, structure and electrophysical properties has been studied. ZrO2 stabilization due to the joint effect of 10 mol.% Sc2O3 and 2 mol.% Yb2O3 provides for the formation of transparent homogeneous crystals with a cubic structure having high phase stability. Mechanical grinding of the crystals has not changed their phase composition, the powders retaining the initial fluorite crystalline structure. We show that the high-temperature electrical conductivity of the crystals decreases with an increase in the Yb2O3 concentration.

We have studied the dependence of the thermoelectric properties of the bulk (Bi,Sb)2Te3 material on the temperature of spark plasma sintering (SPS). For analysis of the experimental results we took into account the regularities of structure formation in the material. The average crystallite size decreases with an increase in the SPS temperature to above 400 °C. Transmission electron microscopy showed that at above 400 °C the bulk and boundaries of the initial grains that are several micrometers in size contain a large number of nanosized grains (approx 10 – 20 nm) having the same composition. We show that the dependence of the thermoelectric properties of the material on SPS temperature correlates with changes in the fine structure of the material which is controlled by the redistribution of the intrinsic point defects. Our results suggest that, along with the well-known nanostructure formation processes, there is one more high-temperature self-organizing process of the formation of the nanostructural material based on the redistribution and change in the form of occurrence of the nonequilibrium point defects. This information can be used to broaden the possibilities of controlling the properties of the bulk thermoelectric material on the basis of (Bi,Sb)2Te3.

Using cathode arc deposition, we have produced nanostructured Ti–Al–Si–N coatings having a multilayer architecture made up of alternating layers of nonstoichiometric crystalline titanium nitride 2–20 nm in thickness and an amorphous Si3N4 phase containing aluminum nitride grains 5–18 nm in thickness. The multilayer architecture, the thickness of the layers, and the particle size of the crystalline phases TiNx and AlN can be controlled by varying the bias voltage applied to the substrate (Vb), the substrate rotation rate (n), and the evaporating arc current (IAl–Si). The TiNx phase in the coatings has high lattice strain because of its compositional inhomogeneity, which increases with an increase in Vb from–60 to–120 V. Further increase in Vb leads to a reduction in lattice strain, which is probably caused by the formation of the ordered nitride phase Ti3N2. The hardness (H), elastic modulus (E), and the parameters H3/E2 and H/E of the nanostructured multilayer nc-AlN–a-Si3N4/nc-TiNx coatings increase with increasing Vb and n. Their maximum values are 56 GPa, 770 GPa, 0.75 GPa, and 0.124, respectively.

The character of the distribution of cerium and neodymium dopants in 95.14 wt % ZrO2–3.67 wt % Y2O3–0.89 wt % CeO2–0.30 wt % Nd2O3 crystals has been studied. It has been shown that the crystal has defect regions due to the violation of normal growth of the crystal, which are depleted in the stabilizing Y2O3 oxide and enriched in Nd2O3 and CeO2 dopants. The existence of inclusions of a monoclinic phase in defect regions has been revealed using Raman and optical spectroscopy. A tetragonal–monoclinic phase transition initiated in the crystal by annealing in air has been investigated.