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Increasing of the hardness and wear resistance of the working surfaces of parts made of aluminum and its alloys is achieved by modifying them by the method of micro-arc oxidation in alkalescent electrolytes. This technology consists in the formation of a highly hard and wear-resistant ceramic layer by means of the spark discharges and implies an enormous investment of energy and time. The finished product surface roughness in numerous cases fails to meet the requirements, and demands additional machining. High hardness of the hardened layer, at the same time causes an increased wear of the processing tool. A method in which the technological process is carried out in two stages allows improving energy efficiency of this technology. At the beginning, when using an electrolyte with a high content of liquid glass, a primary oxide layer, consisting predominantly of silicon oxide, is formed. At the next stage of micro arc oxidation, the content of the liquid glass in the electrolyte decreases, which allows the formation of predominantly high rigid aluminum oxide in ceramic layer. This technology can significantly reduce the time of formation of a coating and reduces energy consumption. To reduce the processing tool wear it is proposed to keep the surface of the modified by oxidation workpiece in hydrofluoric acid for 5 - 30 minutes. This operation allows to reduce the hardness of the upper layer, consisting mainly of silicates, without affecting the lower layer, formed mainly of aluminum oxide. As a result, it is possible to receive the required surface micro geometry with less tools wear, less time and energy. There was achieved a reduction of time for getting the finished product by 1.6 - 2.3 times, electricity by 2 - 2.7 times, tool wear by 8.7 - 12 times.

The paper presents a developed a technology for producing a new abrasive material, which is a refractory ceramic matrix made of aluminum oxide with embedded diamond particles. The tests have shown its advantage over traditional diamond-bearing materials when processing high-hardness ceramics. To synthesize a new material with a predetermined set of operational parameters, it is necessary to build a wear model of a friction pair composed of diamond-bearing ceramic material and ceramics. After analyzing the results of other authors’ studies and assessing the morphology of the contacting surfaces, it is assumed that the contact of microroughnesses on the friction surfaces of abrasive diamond-bearing ceramic tools is linearly elastic. The model is built within the framework of the basic wear equation. The composite material surface was modeled by a set of same radius spherical segments; diamond grains were distributed in the material with a given bulk density. The paper uses the concept of an equivalent surface with the power law distributed of microroughnesses tops. A theoretical relationship is obtained between the micro-and macrocharacteristics of the wear process of a composite ceramic friction pair. The authors established theoretically and confirmed experimentally that the grinding productivity increases with an increase in sliding speed, applied load and diamond grain size. The diamond concentration has no significant effect on the workpiece wear. The established dependencies can help to achieve high productivity of diamond ceramic tools.

An attempt was made to obtain boron-containing MAX-phase by the process of self-propagating high-temperature synthesis (SHS) of Ti3AlC2, replacing some carbon atoms by boron atoms. This was conducted by burning powder mixtures (charges) of the composition 3Ti+2Al+2((1-x)C+xB), where x is the fraction of boron atoms (0.10, 0.15, 0.25, 0.50, 0.75, 0.90), replacing the carbon atoms. X-ray diffraction analysis of the products of combustion have shown that the replacement of carbon with boron to half of the content of carbon atoms in the charge (x=0.10-0.50), does not change the phase composition of the products, including Ti3AlC2 and TiC, but leads to a shift of the peaks of these phases in the diffraction pattern in the direction of smaller angles. When replacing more than half of the carbon atoms with the boron (x=0.75 and 0.90), the peaks of titanium carbide and MAX-phase are not observed, and the XRD peaks appear of the titanium borides TiB and TiB2, and intermetallic compound Al3Ti. Photomicrographs obtained with an electron microscope show that the SHS products synthesized from the charge with replacing up to half of the carbon atoms with the boron represent plates with a thickness of about 1 μm typical for MAX-phases, but rounded particles of borides and intermetallic compound of titanium appear at a higher boron content. Based on these results, it is concluded that replacement of a part (up to 50%) of the carbon atoms with boron atoms in the SHS charge 3Ti+2Al+2C leads to the synthesis of boron-containing MAX-phase based on the crystal lattice of Ti3AlC2.

The composite powder of AlN-BN is of interest from the point of view of the use for sintering the AlN-BN composite ceramics. The ceramics compared with AlN ceramics would have better thermal shock resistance, less britlleness, better machinability, good heat conductivity and tribological properties. Possibility of obtaining a composite powder of AlN-BN with the application of process of self-propagating high-temperature synthesis (SHS) from powder mixtures of NaN3 and precursors of aluminum and boron was investigated. Halide salts AlF3, Na3AlF6, KBF4 and NH4BF4 were used as the precursors. It was shown that these mixtures are capable of burning and obtaining agglomerated composite powders from nanosized (50-170 nm) particles.

Processes and products of combustion of systems of "sodium azide – aluminum and boron halides " are studied. Halide salts AlF3, Na3AlF6, KBF4 and NH4BF4 are used as precursors of Al and B elements. The measured combustion temperature is in the range from 900 to 1800°C. It is established that the end product of combustion synthesis consists of several phases, not only the target phases (AlN and BN), but also the by-products (Na3AlF6, К2NaAlF6, NaF, KF), part of which is removed by water washing. The composite powder of AlN-BN is formed only in the case of AlF3 as precursor of Al; in doing so, it is formed with side, impurity product К2NaAlF6 or Na3AlF6. In the case of precursor Na3AlF6, the washed product of SHS may only be a by-product К2NaAlF6 or Na3AlF6 or along with the by-product, it may contain AlN or BN, but not their composition. That is explained by different combustion temperature.The structure formation of the composite powder is investigated. The obtained agglomerated nitride nano- and micropowders have an irregular and predominantly acicular shape with an average particle size of 50-170 nm in the agglomerates.

One-stage technology of obtaining aluminum-ceramic skeleton composites by combining the processes of self-propagating high-temperature synthesis (SHS) of the porous skeleton and its infiltration under pressure with molten aluminum (method SHS-pressing) was considered. Experimental study of the effect of the pressure of infiltration on the distribution of the content of aluminum over the height and radius of the disk-shaped sample with SHS skeleton made of a cermet of TiC-Ni was performed. Mechanisms of the formation of structure and properties of the composite depending on the infiltration pressure were described.