It has been examined that when an oxide layer is treated under atmospheric conditions on a treated substrate surface, in the contact zone, an oxide layer is always present. This mixed oxide layer influences the contact temperature and the adhesion strength of the particles that are being coated to the substrate surface.Henceforth the process of heating of the contact layer of surface oxides was investigated. The experimentation was demonstrated by coupling of the particles of the coating layer with the surface layer when wetting is provided by melting of the oxide layer. The conditions of the wettable contact under nonstationary heat exchange were determined depending on the thermophysical properties of the contact pair, the temperatures of the coating particles and the substrate. The wetting time was evaluated depending on the thickness of the oxide layer. The identity of the adhesion strength of the coating and the cohesive strength of the oxide layer was substantiated. It was evaluated that for the inner surface of the coating elastic modulus and breaking stress is about 20% higher than for the external. The detected difference is related to the presence of the temperature gradient across the thickness for coating.

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Purpose. To increase the efficiency of the plasma coating by developing a method of ion-arc activation of the base using an activating electrode, which leads to an increase in the adhesion strength of the coating due to the sputtering of surface oxides of the base. Research methods. Experimental and computational, mechanical tests, optical microscopy. The development of the method of ion-arc activation of the part base with an increase in the distance of coating deposition consists in application of an activating electrode located at the surface of the base to create an additional activating arc. The influence of the activating arc on bases for creating an additional activating arc. The influence of the activating arc on the adhesion strength of the coating is determined. The estimation of the current density of the activating arc for the sputtering of surface base oxides is carried out. Results. A method of arc activation of the base surface with an increase in the coating distance is found. It is shown that application of an activating arc of reverse polarity that burns between the additional electrode and the base leads to ion bombardment of the surface by sputtering surface oxides and the creation of microcraters on the base surface. As a result, the bond strength is doubled compared to the bond strength obtained without the use of ion-arc activation of the base. The calculations of the rate of cathodic sputtering of the surface oxides of the base are carried out and the minimum activation current density of the base is determined, which leads to the complete sputtering of a layer of oxides of a given thickness. Scientific novelty. It has been determined that, despite the rapid oxidation of the base under atmospheric conditions, application of the method of ion-arc cleaning of the surface during coating leads to a significant increase in the adhesion strength of the coating to the base. Practical value. The obtained results of increasing the adhesion strength rise the efficiency, the guaranteed service life of the plasma coating on the parts of machines and mechanisms