Вплив плазмового стану речовини на дифузію атомів при електролізі1 Дніпропетровський національний університет ім. Олеся Гончара, пр. Науковий, 13, 49050, Україна,

The structure and properties of a multicomponent diffusion layer obtained on steel as a result of joint saturation with boron and other elements (silicon, molybdenum, tungsten) during chemical-thermal treatment (CTT) are investigated in this work. As a result of multicomponent saturation of the steel surface pre-treated by deformation of various intensities (electrolyte plasma, pressing, explosion) a multiphase microstructure of the diffusion layer with higher micromechanical characteristics of the steel surface in comparison with ordinary boron saturation is obtained. As established, the pre-treatment of steel surface at saturation under conditions of a multicomponent CTT accelerates diffusion processes and contributes to the spread of finely dispersed inclusions from refractory boride compounds to a greater depth. This ensures the formation of a multilayer complex coating with unique properties.

Copper and its alloy were treated in an electrolytic plasma formed in the boron-containing electrolyte under the action of discharge in order to obtain a diffusion coating with enhanced hardening characteristics and the structural changes in the surface layer of the metal that occur in this case were studied. As a result of processing in electrolytic plasma, characterized by high heating and cooling rates, a diffusion layer was formed on the surface of copper and an alloy based on it (brass). The layer contains nanosized inclusions of copper borides, ternary compounds Cu-B-H, Cu-B-O concentrated mainly along grain and phase boundaries and providing hardening of the metal surface. The action of the discharge provides structural and phase transformations in the metal, the deformation of the grains - elongation in the direction of the driving force (electric transfer) at a depth of 100 μm and the creation of metastable states in the surface layers.  Moving vacancies and compressing atoms in the direction of the force create conditions for the rapid movement of boron atoms. With increase in current density and time of treating, the size of nanostructures decreases. Their size is of the order of 6-16 nm. Obtaining wear-resistant coatings on copper and its alloys, which include phases containing copper and boron, increases the strength characteristics of copper and its alloys by 1.5-2 times.

In this paper, the formation of a diffusion layer on aluminum, which includes aluminum hydrides, in non-equilibrium conditions of electrolyte plasma with high local temperatures, high heating and cooling rates were studied. As a result of the research it was obtained that in the diffusion layer formed complex nanosized inclusions of polymorphic modifications (AlН3)n and AlB3H12. The diffusion in the non-equilibrium conditions of the electrolyte plasma is carried out in hydrogen environment, where the hydrogen atoms have the greatest energy and is one of the main forces that activate the diffusion process and influence the structure, composition and micromechanical characteristics of the diffusion layer.

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