For obtaining new metal matrix composites, one needs to develop approaches to the selection of reinforcing additives, the identification of the relationship of the properties of the resulting material with the composition, concentration and morphology of the additives introduced, the creation and search for new affordable and cheap additives. As one of the solutions to this problem, the authors propose to obtain aluminum matrix composites based on the structuring of an Al matrix with titanium carbide nanostructures (<= 5 nm) by atomic layer deposition (ALD). The resulting material has an important feature- the absence of obvious interface boundaries between the Al matrix and the reinforcing carbide phase, that ensures the components binding into a single whole. Composites, for the hardening of which a reinforcing phase with surface carbide nanostructures is used, in addition to a higher tensile strength, demonstrate a more plastic fracture pattern characteristic of dispersed hardening of materials. With an increase in the amount of the composite reinforcement from 1 to 5%, embrittlement of the material does not occur, as is observed when carbide particles are introduced into the Al matrix by other methods.

The most important task of modern mechanical engineering is the combination of high strength with a sufficient margin of the material plasticity. The solution to this problem is the use of metal matrix composite materials. One of the ways to strengthen a metal matrix is its reinforcement, i.e. the introduction of structures with high hardness and strength into the matrix. At the same time, Ni-based materials are of particular interest due to their increased heat resistance. However, the introduction of a dispersed reinforcing phase into the matrix leads to embrittlement of the material, which leads to difficulties in processing it. As a result of our research, an approach was proposed to obtain a metal matrix composite material using the surface structuring process and the powder metallurgy method. The developed approach made it possible to obtain a composite material where titanium carbide (TiC) nanostructures of about 2 nm in size are evenly distributed in the Ni matrix bulk. An important feature of the composite being developed is the absence of explicit interface boundaries between the metal matrix and the reinforcing element. This ensures the binding of the matrix and the reinforcing phase into a single whole. The resulting composite effectively resists plastic deformation and stresses. This allows not only to influence the strength properties of the material as effectively as possible, but also to preserve its plasticity.

The work relates to the nanotechnology and composites with a metal matrix and nanoscale reinforcing structures. A technique was developed for obtaining a composite material with a uniform distribution of dispersed phase particles in the volume of the aluminum matrix using the injection molding method. The process of mixing the Al melt and the dispersed phase has been studied. An increase in the strength of the obtained composites by 1.5 times compared with pure Al and the preservation of plasticity is observed for all obtained samples of composite materials, in which the dispersed reinforcing phase are TiC nanostructures obtained during chemical assembly on the surface of aluminum particles. Composites obtained by injection molding, for which a reinforcing phase with surface carbide nanostructures is used, in addition to a higher tensile strength, demonstrate a more plastic fracture pattern characteristic of dispersed hardening of materials. With an increase in the volume of reinforcement of the composite from 1 to 5 %, embrittlement of the material does not occur.

Abstract The development of metal matrix composite (MMC) materials is one of the demanded areas of research in materials science. In line with this trend, there is an increasing interest in nickel-based MMC materials, which have already become classic in science and technology. This is due to the high demand for Ni-based materials with high strength characteristics, high hardness, and increased heat resistance. In this research, we proposed an approach to obtain a MMC material using the surface structuring process, ALD (Atomic Layer Deposition) and powder metallurgy method. The developed approach provides a composite with TiC nanostructures (1-5 nm) uniformly distributed throughout the Ni matrix. The absence of interphase boundaries between the Ni matrix particles and carbide nanostructures made it possible to minimize the internal porosity of the sample. This is due to the strength of the interphase boundaries between the matrix and the reinforcing phase in the composite and to the solidity of the structure. As a result, the created material effectively resists plastic deformation and stress. This allows not only to enhance the strength properties of the composite, but also to maintain the MMC plasticity, which increases its processing ability.

The main direction in obtaining metal-matrix composites (MMCs) with a multilevel hierarchical structure is the development of new approaches to the creation of materials with two or more reinforcing modifiers, which makes it possible to improve a whole range of functional properties and, at the same time, reduce the total cost of the material. Carbon nanotubes and carbide particles additives can significantly improve the strength properties of aluminum and its alloys. In this work, the possibility of directed control of the composition, the structure and properties of composites was shown, using the methods of powder metallurgy and surface modification. As a result of the study, aluminum-based MMCs reinforced with carbide nanoparticles and carbon nanotubes (CNTs) with a Ni-plated surface were synthesized. As a result, it was shown that the combined use of two reinforcing phases makes it possible to diminish their negative qualities in the bulk of the metal and obtain a composite material with high strength properties while maintaining plasticity.

To create titanium-based bone implants, it is urgent to create bioactive coatings that ensure their rapid engraftment. The rate of fusion of Ti implants with bone tissue is significantly affected by the degree of implant surface modification based on changes in the relief or chemical composition of the surface layer, as well as a combination of these two approaches. In this work, we investigated the possibility of creating composite coatings with a two-level hierarchy of the surface topography at the micro- and nanolevels with bioactive and bactericidal properties that are promising for bone implantation. A technique for template electrochemical synthesis of a composite coating with directional control of the titanium surface structure based on titanium dioxide, silver, and hydroxyapatite was developed. Studies have shown that the TiO2/Ag composite coating with an island-like microstructure and a pore size of 5-20 nm has a significant cytological response and the ability to accelerate osteosynthesis. Thus, the developed biomaterial can be used to manufacture implants with improved biomedical properties for dentistry and orthopedics.

The presented work is devoted to the study of the possibility of using planar materials consisting of ultramicroelectrode arrays for voltammetric analysis of compounds with close redox potential, but with different diffusion coefficients, which has great prospects in the analysis of various oligomers, including oligopeptides. A feature of the electrochemical behavior of materials containing arrays of ultramicroelectrodes is the realization of hemispherical diffusion, which can lead to the steady state or unsteady state regime of the electrode depending on the intersection or non-intersection of the hemispheres. There is also a transient mode of operation of electrodes at partial intersection: voltammetry diagrams obtained in this mode may contain analytical information on the concentrations of substances with one redox potential, which favorably distinguishes the approach from the classical cyclic voltammetry using macroelectrodes. The prospects of the proposed approach are confirmed by the example of analysis using ultramicroelectrode arrays of ferrocenemethanol and triglycene ferrocenemethanol ester. The results obtained prove the possibility of applying the approach to the analysis of electroactive oligopeptide derivatives.

The main technological problems in the synthesis of metallic composites containing carbon nanotubes or carbide particles are the distribution of the hardening phase in the bulk composite, the strength of its adhesion to the matrix, as well as the chemical and structural stability of the dispersed phase within the composite. These tasks are solved in various ways, primarily at the stage of preparation of the dispersed phase and the monolithic composite matrix. In our work, to ensure good wettability of the dispersed phase and uniformity of its distribution in the bulk aluminum, carbon nanotubes and carbide were metallized with a thin layer of metallic nickel. In the course of work on the creation of aluminum matrix materials reinforced with carbon nanotubes, the necessary conditions were selected for the formation of a metal matrix composite material with improved mechanical properties.

Increasing the duration and quality of human life requires solving a number of medical and materials science problems, in particular, the creation of materials designed for long-term work in contact with the biological environment. When creating such materials for medical devices, it is necessary to take into account that they must meet strict requirements, namely, be biologically compatible with tissues, have corrosion resistance to various biological fluids and have increased wear resistance. The study of the effect of Ti microstructure on microhardness and its corrosion resistance in physiological environments is necessary to create implants designed for long-term work in contact with the biological environment of the body. In accordance with this, the purpose of this work was to establish the nature of the relationship between the structural properties of ultrafine-grained Ti with different sizes of crystallites (grains) obtained using equal-channel angular pressing (ECAP) of different intensity, namely with a different number of processing cycles, on the microhardness and stability of Ti in a corrosive environment.

Metal–matrix composites based on an aluminum matrix reinforced with ceramic particles are widely used as structural materials in the aerospace and automotive industries. The main problems in the manufacture are the uniformity of the distribution of particles over the volume, poor adhesion of ceramic particles to the matrix metal, and the formation of aluminum carbide at the interfaces, leading to undesirable embrittlement. We propose a new technique for the manufacture of metal–matrix composites, which consists in creating a composite material, when carbide nanostructures form a framework in the volume of an aluminum matrix, and which allows solving the above problems. A finite element model of deformation of a metal–matrix composite reinforced with carbide structures is constructed.

An aprotic lithium-air battery is a promising candidate for next-generation energy storage systems, but its practical performance is still low. The addition of water to an electrolyte can substantially increase the capacity and round-trip efficiency of batteries. However, fundamental mechanisms of the water impact are still far from being fully understood. To contribute to this issue, we studied by molecular dynamics simulations the effect of water additives on the behaviour of discharge intermediates Li+ and O2- in two frequently used solvents: dimethoxyethane (DME) and dimethyl sulfoxide (DMSO). We have estimated the structures of the solvation shells around Li+ and O2- ions, and the residence times of various electrolyte components inside the solvation shells depending on the concentration of water additives. Furthermore, we have estimated the rate and the equilibrium of the Li+ and O2- association. Our results reveal that water additives in electrolytes shift the equilibrium of the association reaction toward soluble Li+ and O2- ions in both DME and DMSO. These data argue for the view that water promotes the solution discharge mechanism, thus increasing the capacity. Moreover, we show that water accelerates the kinetics of the association reaction due to the decrease of the stability of Li+ and O2- solvation shells. This may explain the reduced discharge overpotential when water is added.

Implant-associated soft tissue infections at the skin-implant interface represent the most frequent complications in reconstructive surgery and lead to implant failures and revisions. Titanium implants with deep porosity, called skin-and-bone-integrated-pylons (SBIP), allow for skin ingrowth in the morphologically natural direction, thus restoring a reliable dermal barrier and reducing the risk of infection. Silver coating of the SBIP implant surface using physical vapor deposition technique offers the possibility of preventing biofilm formation and exerting a direct antimicrobial effect during the wound healing phase. In vivo studies employing pig and rabbit dorsum models for assessment of skin ingrowth into the pores of the pylon demonstrated the safety of transcutaneous implantation of the SBIP system. No postoperative complications were reported at the end of the follow-up period of 6 months. Histological analysis proved skin ingrowth in the minipig model without signs of silver toxicity. Analysis of silver release (using energy dispersive X-ray spectroscopy) in the model of intramedullary-inserted silver-coated SBIP in New Zealand rabbits demonstrated trace amounts of silver after 3 months of in-bone implantation. In conclusion, selected temporary silver coating of the SBIP implant surface is powerful at preventing the periprosthetic infections without imparing skin ingrowth and can be considered for clinical application.

The article considers a new approach to the synthesis of metal composites based on the structuring of an aluminum matrix with titanium carbide nanostructures. A method is developed for the uniform introduction of a metal- ceramic-metal reinforcing additive into the bulk aluminum-based composite (Аl–TiC–Fe). As a result, a composite with improved mechanical properties was obtained, where ceramic nanoparticles are evenly distributed in the bulk metal matrix. The ways of adjustment of the mechanical characteristics of composites using aluminum matrix structuring with carbide nanostructures are shown.

In the present work the possibility is considered of a chemical sensor synthesis for quantitative glutathione (GSH) determination. Sensor is based on a composite working electrode containing an array of micron-sized Ag particles immobilized on a conductive substrate (Ti) coated by dielectric TiO2 film. To determine GSH in biological fluids, particularly, in saliva, electrochemical silver-based sensors can be used, since such sensors contain -SH group. With the use of cyclic voltammetry (CV) with a composite working electrode containing an Ag microparticles array, the threshold of quantitative GSH determination is reduced to nM level. Since other modern analogues are inferior at least one order of magnitude in the limit of quantitative GSH detection, we assume that the proposed sensor may be of great interest for clinical diagnosis.

The article discusses a new approach to the synthesis of metallic composite materials based on nanostructuring of a metal frame (on the example of iron) by SiC nanostructures (10-50 nm). Optimal conditions are established for the nano-SiC coating on the porous Fe surface during sequential chemisorption of Cl2Si(CH3)2 and CH4 molecules from the gas phase. The resulting composite possesses enhanced strength in comparison with the best steel samples although the residual porosity (up to 5%) of Fe matrix is still preserved after pressing.

The features of the porous nickel surface preparation for conducting the chemical processes of nanostructuring the dispersed phase TiC on the nickel surface were studied.

Разработана методика синтеза суперпарамагнитных наночастиц магнетита в порах мезопористых кремнеземов МСМ-41. Изучена зависимость магнитных свойств нанокомпозитов МСМ-41/Fe3O4 от радиуса пор синтезированного кремнезема МСМ-41.

The important stage of the development of smart material for the target drug delivery is the construction of the magnetic part of this material, including mesoporous silica and magnetic nanoparticles (Fe3O4or Fe0). Such a systemwill allow carry outmagnetic decapsulation (excretion) of drug from smart material using the magnetic field of a given value in the right place of the body. The paper considers the features of synthesis mesoporous silica MCM-41 with various pore diameter (33-51 Å) and synthesis of superparamagnetic nanoparticles of magnetite or metallic iron in the pores of mesoporous silica. The dependence of magnetic properties of nanocomposites MCM-41/Fe0 and MCM-41/Fe3O4 from the pore diameters of MCM-41 templates is studied. It was found that the matrix has a decisive influence on the content of iron or magnetite nanoparticles. The saturation magnetization of the material increases with increasing pore size of the mesoporous matrix. Nanocomposites MCM-41/Fe0 and MCM-41/Fe3O4 exhibit superparamagnetism, that allows them to be used as a magnetic material for targeted drug delivery.

Conditions were determined for the synthesis of TiO2 mesoporous thin films on silicon by the solgel method in the version of coating by dipping silicon plates in a TiO2 sol (dip-coating).