The relevance of research is connected with the use of ceramic filters in biology and medicine for fine filtration of air and biological fluids abroad. Due to the unique combination of chemical and thermal resistance, high strength and thermal conductivity, ceramic filters are used to clean aggressive liquids, superheated high pressure steam and other gases. The dependence of burning rate on the relative density and granulometric composition of FeTiO₃–Al–Si–SiO₂–C powder mixtures is studied. The paper provides experimental results on the influence of initial charge compact density and composition on the quality of products obtained. The main types of defects appearing in the synthesis are identified. The causes of defects are found. Feedstock with particle sizes larger than specified values results in penetrations (cavities) occurring in the product. Their formation is caused by the increased liquid phase content in these regions due to decelerating reaction rate and rising temperature. Higher density results in transverse and longitudinal laminations in the product. Such laminations are formed under the pressure of gaseous products with the low gas permeability of the sample that declines as density increases. The technology of self-propagating high-temperature synthesis of large porous products is developed with the photographs of filtering elements presented: for the typical industrial gas burner GG-2, for superheated steam and demineralized water purification (filtering elements used in polyvinyl chloride process vessels at JSC «Sayanskkhimplast»), for iron removal from artesian water. Defect-free large porous products can be obtained with an optimal ratio of the sample grain size distribution and density, as well as reaction rate and heat removal rate.

The phase formation of Ti–Al–C powder mixtures with compositions close to the composition of the MAX phases in self-propagating high-temperature synthesis (SHS) was investigated using time resolved X-ray diffraction. It is found that material formation during combustion in air under low heat removal rates is a staged process. At the first stage, the dominant is the reaction of titanium carbide formation providing major heat release and combustion front propagation. As a result, TiC crystals surrounded by the Ti–Al melt are formed. Behind the combustion front titanium carbide dissolves in the surrounding melt and then the Ti₂AlC ternary compound is crystallized. TiC formation is not observed with the synthesis in helium providing high heat removal rates. The first phase emerging on the diffraction field is Ti₂AlC. The TiC life cycle of 5–10 s for air-synthesized mixtures is significantly reduced for helium processes and does not exceed 1 s. SHS reaction in helium yielded a Ti₂AlC-based composite containing less than 20 wt.% of TiAl, and 2 wt.% of TiC. The material structure is characterized by laminated Ti₂AlC grains surrounded by the TiAl matrix. The microhardness of synthesized materials was 4,0–4,5 GPa that corresponds to that of the Ti2AlC phase. Ti₂AlC grains synthesized in helium are smaller than in air. Laminated MAX-phase grain sizes grow up to 8–15 μm in length and 2–5 μm in width at slow air cooling. The Ti₂AlC grain size in helium is lower – up to 8 μm in length and 1 μm in width.

The multi-method investigation of Cu–ZnO (nano), Cu–TiN (nano) copper-based materials using standard mechanical testing methods along with metallographic, electron-microscopic research using energy-dispersive and thermal analysis allowed to identify stable correlative relationships between the content of nanoparticle additives, microstructure parameters and mechanical-and-physical properties of pseudoalloys. Processing technologies are suggested and justified to improve the uniform distribution of ZnO and TiN modifying nanoparticle additives over the pseudoalloy volume eliminating their conglomeration. The paper proposes novel original methods of nanoparticle introduction to the matrix material as master alloys of Cu–Al–ZnO or copper powders coated with TiN nanoparticles. High surface area and reactive capacity of nanopowders provides for reduced ceramic phase in electrocontact materials (down to 2,0–3,0 % instead of 10–15 % compared with known commercial ones). In this way, general properties typical for matrix materials (copper), i.e. heat and conductivity, remain significantly high, and at the same time, the general level of mechanical-and-physical properties of composite pseudoalloys such as hardness, strength and wear resistance as well as their operational properties is increased. Main properties of copper-based composites include resistivity (ρ ~ 0,025 μΩ·m), strength of bonding to  Тугоплавкие, керамические и композиционные материалы 20 Известия вузов. Порошковая металлургия и функциональные покрытия  4  2017 the contact support material (σ ~ 2 MPa), dispersed ceramic phase inclusions that reduce electroerosive wear (2,5 times) in comparison with conventional materials.

Currently, critical components and assemblies made of traditional materials not always meet the increased requirements of designers and service conditions. One of the solutions to this problem is the development and application of dispersion strengthened metal matrix composites. According to the information analysis review, the paper suggests a new technology to produce dispersion strengthened aluminum-based composite. Features of the developed technology are specified along with both sample macroand microstructures and mechanical characteristics of as-cast samples. Strengthening particles are synthesized directly in the melt so that composites can be produced in a single stage with high thermodynamic stability, dense contact and good adhesion between the matrix and the strengthening phase. The reached particle sizes of a solid interstitial phase range from 3 μm to 2 mm. The structural and phase state of the produced material was studied using optical metallography and the X-ray diffraction analysis (Dron-2 diffractometer). The microstructure was investigated using the Keyence VHX-1000 microscope. Measurements were carried out using TKS-1M to determine microstructure, PMT-3 and HMV Shumadzu to determine hardness, ZD 10/90 and UME-10TM universal tensile testers to determine tensile strength, and MK-30a pendulum impact tester to determine impact strength. It is found that the variation in the strengthening phase size and content allows changing mechanical properties of cast metal over a wide range. Estimate calculations show an expected reduction in the cost of dispersion strengthened composite production.

Modern scientific technical information implies great prospects for the use of Al–Al₂O₃ based composite materials (CM). The papers by the Materials Science Department of Moscow Aviation University have shown the reactive air sintering of highly-dispersed PAP-2 powder blanks to be a promising way of obtaining the aluminum-base CM. However, it is necessary to solve a number of technological problems to apply the above technique such as the lack of fluidity and extremely low apparent density. The paper studies and suggests various methods of PAP-2 aluminum powder granulation with their physical and chemical aspects described. Various technological approaches to PAP-2 aluminum powder granulation have been used based on such process operations as powder heating in air followed by isothermal aging at 350 °C, adding water solution of sodium-silica glass, mechanical processing of powder in high-energy planetary mill, its heat treatment in vacuum at 650 °C initiating the stearin saponification reaction on the surface of the PAP-2 flakes followed by the formation of the organic component – plasticizer. It is found that the proposed methods of industrial  PAP-2 powder granulation can modify its composition and structure as well as improve and vary technological characteristics of the original powder. The highest value of apparent density (up to 1,25 g/cm³) is achieved when using mechanical treatment of the original powder in a high-energy planetary mill with the formation of rounded granules 50–150 μm in size. The most producible and cost-effective technique is based on initiating the chemical reaction of «stearin saponification» on the surface of powder particles (with apparent density of approximately 0,4 g/cm³).

Direct laser deposition of metal powders is one of the additive methods of functional product manufacturing. It consists in metallic powder melting with laser beams in the inert gas atmosphere. Main process parameters include laser beam power, speed, scanning strategy and powder consumption. Each of the parameters is selected depending on the alloy type that jointly affects the structure and defect formation in products. The present paper shows that the experimental rectangular specimens of powder austenitic steel 316L were obtained by direct laser deposition. The microstructure and fractures of samples were studied using scanning electron microscopy in order to determine the structural features and identify any defects (pores, holes, crystallization cracks and oxide inclusions). Uniaxial tensile tests and hardness tests were carried out. The effect of laser beam scanning strategy on the microstructure and properties of samples when melting was analyzed It was observed that a dispersed structure with an average crystallite size of 1,3–1,9 μm is formed at 250 W laser power and 16 mm/s scanning speed that causes a high level of mechanical properties of experimental samples. It was shown that tensile strength at the lengthwise strategy (along the largest sample size) was up to 730 MPa with an elongation rate 25 % that exceeded 316L steel mechanical properties by 110 MPa.

The processes of aggregation and sedimentation of ultradispersed diamonds (UDD) in citrate copper plating electrolyte used for obtaining composite electrochemical coatings was investigated. The study of sedimentation and aggregation resistance was carried out for the purpose of selecting the concentration of UDD in citrate copper plating electrolyte. It was necessary to obtain composite copper plating featuring advanced operational properties (increased hardness, wear resistance, corrosion resistance), as well as to attain new properties (antifriction, catalytic). UDD content in electrolyte varied from 0,2 to 2,0 g/l. UDD particle size distribution in electrolyte was determined using the Malvern Mastersizer 2000 laser diffraction analyzer both as soon as suspension had been prepared and after 10-day holding. Aggregation and sedimentation resistance of UDD suspension in citrate copper plating electrolyte was investigated gravimetrically with a continuously weighed quartz cup immersed into the above mentioned suspension. The quartz cup was connected to the Sartorius R200D analytical balance by quartz fiber. The above experiment resulted in obtaining the relationship between the mass of UDD debris and the time Q = f(t).The obtained relationship was used to determine the relative particle size distribution. Sedimentation resistance has been proved to be greatly affected by the process of particle aggregation intensified by means of diamond concentration strengthening. Appropriate aggregation and sedimentation resistance results were derived from UDD suspension in citrate copper plating electrolyte at a concentration of 1,0 g/l. In this case the combination of high disperse phase content and aggregation and sedimentation resistance produced copper composite coatings with enhanced operational properties.

The paper focuses on metal surface nanostructuring and functional coating application using a flexible tool – rotating wire brushes (RWB). This process called friction cladding implemented on lathes, grinders and other machine tools using ordinary tooling or manual angle grinders. Metallographic investigation of surface layers used 3×20×100 mm plates made of Steel 08 as study samples. Coatings were applied using the surface grinder where RWB was installed instead of an abrasive disk together with a coating material feeding device. Cylindrical samples (Steel 50) 20 mm in diameter were machined by angle grinders installed on the sliding carriage of the lathe. Optical microscopes and the JSM-6490 LV electron-scan microscope (ESM) were used for metallographic research. Electron microscopic studies were performed by replica technique using the Tesla BC-613 electron microscope. X-ray diffraction analysis was performed on the Dron-3 diffractometer. Measurements and surface roughness analysis were performed according to the GOST R ISO 25178 method on the Bruker Contour GT K1 unit. The surface structure, texture and microtopography of copper and brass coatings deposited using a flexible tool on a steel base were investigated. The average coating thickness was 20–25 μm, microhardness was about 6800 MPa for the copper coating and 9000 MPa for the brass coating with particle sizes ranging from 0,3 to 0,6 μm. The crystallographic texture of the coating reproduces the texture of the steel base material. Investigation of sample surface microtopography before and after coating showed that the brass coating substantially smoothes out the surface, but the initial microtopography is changed insignificantly. Copper coating microtopography differs substantially from the initial one.

Titanium-based alloys are widely used in various industries thanks to a combination of high mechanical properties and low density. The most effective use of these properties is making aircraft components and medical implants. Shape memory alloys based on titanium nickelide (nitinol) are promising materials for production of superelastic medical implants and tools as well as thermomechanical elements in aerospace technology. The combination of these materials used as the elements of hybrid structures or composites can allow the creation of products with a unique set of properties such as high mechanical properties, superelasticity and damping capacity, increased wear resistance, and thermal shape memory. The basic properties of alloys based on titanium nickelide and the most widely used titanium alloy VT6 (Ti–6Al–4V) are analyzed. It is found that the functional properties of nitinol combined with structural properties of titanium alloys in an integrated structure make it possible to make a variety of products, especially for aerospace and medical industries. The possibilities to make high-strength permanent joints of titanium alloys with nitinol are analyzed. Various methods of welding (generally laser and diffusion welding) and soldering are currently investigated in order to produce such structures, and best prospects are associated with the use of intermediate layers that eliminate brittle intermetallic phase formation in the permanent joints.