Industrial technologies that employ fast heating and cooling of surface layers of articles for their hardening are widely applied nowadays. For many steel grades, the duration of thermal pulse should be less than 1 ms. Data on the experimental determination of this technological parameter are lacking; therefore, in the work presented, a method is proposed that serves to solve this task via investigation of diffusion of light elements into steel directly in the course of surface treatment. The application of diffusion method is favored by the presence in the atmosphere of oxygen, nitrogen, carbon, and hydrogen atoms upon treatment of the article surface, their diffusion coefficients in iron and steels at high temperatures, strong temperature dependence of the diffusion coefficients, characteristic values of the critical quenching rate for steels, metrological characteristics of nuclear -reaction -based methods and secondary ion -mass spectrometry upon studying diffusion in solids, and other factors. Approbation of this method was carried out based on the data on nitrogen diffusion gained by the method of nuclear reactions. Steel specimens were modified with argon plasma; the plasma source worked in the stationary mode and pulse heating and cooling of the surface were performed by moving plasma torch across the specimen surface. Such technology provides hardening of steel specimens at a depth of about 1 mm and the duration of thermal pulse obtained by diffusion method was less than 1 ms. The diffusion method is promising for characterization of surface treatment technologies for steel items using plasma, high frequency currents, and laser irradiation.

Based on the analysis of the results of theoretical and experimental research, this study develops criteria that metals must meet for it to be possible to observe hydrogen tunneling in metals, as well as methods for measuring quantum diffusion coefficients. Firstly, the distance between the nearest equilibrium positions of hydrogen atoms in the metal lattice must be small enough, about 0.15 nm. Secondly, the Debye temperature of the metal must be low enough, below 350 K. Thirdly, the necessary condition for observing hydrogen tunneling is a correct choice of methods for measuring hydrogen diffusion coefficients. If the hydrogen diffusion coefficient according to the classical migration mechanism is about 10–11 m2/s or higher in the Debye temperature range, it is expedient to use indirect methods based on the Gorsky effect or on measuring the spin lattice relaxation rate via nuclear magnetic resonance (NMR). At lower values of the classical diffusion coefficient in the Debye temperature range of metals, to observe quantum diffusion, it is necessary to use the technique of direct online nuclear reaction analysis (NRAOL) alone or in combination with nuclear reaction analysis (NRA).

It has been found that low-temperature annealing in air changes the defect structure of YSZ10 oxide nanoparticles synthesized by means of the laser evaporation of a ceramic target. The study is carried out with the use of deuterium probes. At a temperature of 350 ℃, with increasing annealing time, a monotonic decrease in the concentration of oxygen vacancies near the surface of nanoparticles is observed. This dependence is extreme at 200 ℃; at its first stage, the concentration of vacancies in the surface atomic layer of nanoparticles increases with time. An approach is proposed for the synthesis of nanoparticles with severe oxygen deficiency near the surface of oxide

The composition, structure and corrosion behaviour of CrxAly(SOC coatings fabricated by the arc discharge techniques using Cr-Al-Si and graphite cathodes were studied. X-ray photoelectron spectroscopy, X-ray energy-dispersive spectroscopy, nuclear reactions, and Rutherford backscattering methods were applied to determine composition of the coating, X-ray diffraction and transmission electron microscopy - to investigate the structure of the coating. Corrosion tests were performed in an electrochemical cell in a 3.5%NaCl solution. Depletion of the cathode surface of chromium, screening of Cr+ by C+ in plasma, and selective etching of the coating upper layers are accompanied by a decrease of Cr/(Al +Si) ratio in the coatings compared to the cathode. The carbon content (C-C) in CrxAl(Si)(y)C, determined by XPS, EDS and NR, differs by several times. The C-C, measured by NR correlates with the results of Raman spectroscopy and confirms the existence of a continuous carbon matrix in CrxAly(Si)C. Cr is chemical bonded with carbon, silicon - with carbon and aluminum. The Al-Si system provides the structure feature of CrxAl(Si)(y)C: a network of aluminum intersects the amorphous matrix. The mechanical mismatch and weak bond between the Al structures and the amorphous matrix may be the reason for the formation of defects in the form of cracks and microchannels along the boundaries.

Reduction of ZrO2 by lithium during electrolysis of LiCl-KCl-Li2O melt at 650 °C was studied using a set of physicochemical methods of analysis. Influence of ZrO2 in the space near a molybdenum cathode on the kinetics of the cathode process was established. Possible variations of the electrode reaction associated with the zirconium reduction were proposed. The appearance of ZrO2 in the cathode space resulted in consumption of reduced lithium and in increase in the potential relaxation time of the molybdenum cathode after cathode polarization. Long-term galvanic impulse electrolysis of LiCl-KCl-Li2O melt at 650 °C was carried out using the molybdenum cathode which was immersed into the ZrO2 powder. According to the X-ray fluorescence analysis as well as the method of nuclear reactions the reduction product was presented by the ZrO2, Li2ZrO3, Zr3O phases. Additionally, by alloying the reduction product with tin, the ZrO2 reduction degree to metallic zirconium was estimated, which was close to zero. It was assumed that the main pathway for the appearance of the metallic zirconium in the ZrO2 reduction product during electrolysis of the LiCl-KCl-Li2O melt was direct electroreduction of dissolved zirconium in the melt.

Solid solution $${\text{G}}{{{\text{d}}}_{{2 - x}}}{\text{L}}{{{\text{i}}}_{x}}{\text{Z}}{{{\text{r}}}_{2}}{{{\text{O}}}_{{7 - x}}}$$ with a pyrochlore structure is synthesized for the first time. The cationic composition is confirmed via chemical analysis and nuclear reactions. It is found that the stoichiometry with respect to lithium is retained up to 1100°C. The lattice parameter diminishes in the homogeneity range 0 ≤ x ≤ 0.30, while the free volume of migration grows. Introducing lithium into the Gd sublattice raises oxygen–ion conductivity, due to the emergence of oxygen vacancies and enhancement of their mobility. Maximum conductivity is reached for composition with х = 0.10 (~1 × 10−3 Ω−1 cm−1, 650°C). An assumption is made about the formation of associates of the type $${{\{ {\text{Li}}_{{{\text{Gd}}}}^{{''}} \cdot {\text{V}}_{{\text{o}}}^{{ \bullet \bullet }}\} }^{ \times }}$$ at high contents of the dopant (x = 0.30), accompanied by an increase in the activation energy of conductivity.

The pyrochlore Gd1.55Li0.45Zr2O6.55 was prepared by the solution and solid-state methods. The introduction of lithium in the Gd-sublattice led to decrease in the lattice parameter a = 10.4830(8) Å in comparison with Gd2Zr2O7 (a =10.5346(2) Å). Monitoring of the lithium content in the sample during heat treatments showed a loss of lithium at temperatures above 1100 °C, so, to maintain the stoichiometry of lithium the low temperature sintering methods are required. The sample Gd1.55Li0.45Zr2O6.55 exhibited a predominant oxygen-ion transport over a wide range of temperatures. Although doping did not lead to an increase in the oxygen-ion conductivity compared to Gd2Zr2O7, it caused the suppression of the hole conductivity.

The acceleration method of nuclear reactions is used to measure the content of lithium and oxygen in zirconium oxides. The purpose of the study stems from the fact that there are no direct methods for determining lithium concentration in solids, while lithium is currently widely used for alloying alloys in aircraft construction, nuclear power engineering, electrochemical devices, and other fields of technology. It is shown that satisfactory metrological characteristics of the method are provided when using the 6Li(d, p0)7Li and 7Li(d, p)8Li reactions at a deuteron energy of 650 keV.

The construction of a hermetic transport container for mounting alkaline metal samples in the vacuum chamber of an accelerator during online measurements of the deuterium diffusion coefficients in metals is described. A glass capsule containing an alkaline metal sample is unsealed in a special box with an inert gas atmosphere and the sample is placed in a cylindrical hollow at the surface of a flat metal plate of the container. After this, the hermetic transport container with the sample is fixed in place on a stationary holder inside the accelerator chamber and is unsealed after a high vacuum is attained in the chamber. Sodium samples are assessed using the nuclear reaction analysis. It is shown that the sodium purity in oxygen, carbon, and other low-Z elements meets the requirements of the accelerator technique.

In this work we present the effect of the irradiation by the beam of charged particles (protons and deuterons) on the electrical and structural properties of the bulk AgGe1.6As0.4(S + CNT)(3) glassy composite containing single-walled carbon nanotubes (CNT). Material AgGe1.6As0.4(S + CNT)(3) possessing mixed electronic-ionic conductivity. The contribution of ionic conductivity component forced by silver ions to the total conductivity is not less than 99% at room temperature. Analysis of the Raman and energy-dispersive spectra provided by scanning electron microscopy, revealed that irradiation of AgGe(1.6)Aso(0.4)(S + CNT)(3) leads to structural rearrangements in the glass matrix and changes of the chemical composition of the material. Surface morphology transformation is arising only as a result of the action of sufficiently high intensity and dose of irradiation. There is no significant influence of irradiation by deuterons or protons beam onto ionic conductivity component, while electronic conductivity component was changed according to irradiation parameters and is a consequence of structural rearrangement.

Nuclear reaction analysis online technique has been applied to study the diffusion of deuterium in metals. Investigations ensuring the application of the new method have been performed. These investigations include the development of a device for diffusion annealing of samples in the chamber of an accelerator and an algorithm for taking into account the effect of radiation defects on the diffusion coefficients. Test measurements of the diffusion coefficients of deuterium in nickel in the temperature range from 130 to–60°С have been performed. For negative temperatures, experimental data on the diffusion of a hydrogen isotope in a metal have been obtained for the first time by a direct method and it has been shown that the online nuclear reaction analysis provides reliable data.

The paper proposes and examines an approach to the investigation of the effect of radiation defects on the diffusion coefficients of deuterium in metals with the application of the online nuclear reaction analysis technique (NRAOL).In the development of the method, an assumption was used that the diffusion system is described by two different values of the diffusion coefficients of deuterium, corresponding to the irradiated and unirradiated regions of the sample.The diffusion boundary value problem is formulated and the analytical expression for the calculation of deuterium concentration in the sample is obtained.The simulation calculations are carried out; the depth and time dependences of deuterium concentration in the sample are constructed.A computational algorithm based on the least squares method is developed in order to investigate the effect of radiation defects on the diffusion coefficients of deuterium by NRAOL.Numerical calculations are performed for samples of nickel and sodium by an algorithm-based computer program.

TiAl6V (ELI) has the low density, low elastic modulus and high strength. Biocompatibility of this material allows one to adapt it to human implant production and successfully use in the manufacture of surgical implants. Spherical argon-atomized Ti6Al4V (ELI) (45µm) powder from TLS Technik was used for study. The chemical composition complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for surgical implant applications. Two machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the alloys. Analysis of the oxygen and nitrogen contamination in SLM alloys was done with Van de Graaff accelerator with 2 Mega Volts. It is found that the oxygen concentration in both samples is about 0.2 wt. % and decreases with the increasing of the sample depth; the nitrogen concentration is about 0,02 wt%. X-Ray results show an absence of beta (BCC) phase in both samples. TEM studies found the metastable martensitic structure and silicon nitride Si3N4.

The paper studies the effect of the temperature of nitriding in electron beam plasma, ranging between 250 and 500 °С, on the nitrogen concentration, phase composition and microhardness of the surface of the AISI 321 chromium-nickel austenitic steel in two initial states – quenched undeformed and after nanostructuring frictional treatment. The lowest nitriding temperature (350 °C) for the efficient hardening of the steel has been established. The application of frictional pretreatment with a sliding synthetic diamond indenter in an argon environment is shown to be highly efficient for increasing the depth of the layer nitrided at this temperature. The contribution of the formed S-phase (nitrogen-oversaturated austenite γN) to the intensive hardening of the steel nitrided at low temperatures (300 to 400 °С) is noted.

For cubic zirconia doped with yttrium oxide, data have been obtained that attest to the high sensitivity of the solubility of deuterium in nanopowders to oxygen deficiency in the volume of nanoparticles and to surface structural defects.The investigation is performed on nanopowders synthesized by laser sputtering of a ceramic target.An accelerating technique of nuclear reactions is used to measure deuterium concentration.It has also been found that the deuterium concentr ation on the surface of nanoparticles decreases when they are irradiated with deuterons, this effect being due to the selective sputtering of dissolved deuterium atoms by accelerator beam ions.It is concluded that investigations of deuterium solubility and ion sputtering of deuterium atoms by accelerated deuterons are an effective tool for obtaining information on the defect structure of o xide nanoparticles.

Two machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the Ti6Al4V alloys by the direct metal laser sintering. The chemical composition of powders complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for medical applications. Analysis of the oxygen and nitrogen contamination in DMLS alloys was done with Van de Graaff accelerator with two Mega Volts. It is found that structures of the samples manufactured with two different machines used the same regimes are close to each other. TEM studies found the metastable martensitic structure and silicon nitride Si3N4. It was found that the oxygen and nitrogen contents in both samples are within the normal range for medical grade titanium alloys. (C) 2017 Elsevier B.V. All rights reserved.

 Abstract — Martensitic texture-phase transition in Selective Laser Melting (SLM) Ti-6Al-4V (ELI) alloys was found. Electron Backscatter Diffraction (EBSD) analysis showed the initial cubic beta < 100 > (001) BCC texture. Such kind of texture is observed in BCC metals with flat rolling texture when axis is in the direction of rolling and the texture plane coincides with the plane of rolling. It was found that the texture of the parent BCC beta-phase determined the texture of low-temperature HCP alpha-phase limited the choice of its orientation variants. The {10-12} < -1011 > twinning system in titanium alloys after SLM was determined. Analysis of the oxygen contamination in SLM alloys was done. Comparison of the obtained results with the conventional titanium alloys is also provided.