NANOSTRUCTURING WEAR-RESISTANT COATINGS FOR THE WORKING PARTS OF AGRICULTURAL MACHINES BY VIBRATION PLASMA TREATMENT

Abstract

The use of technologies for hardening the surfaces of machine parts and mechanisms using concentrated energy flows increases the competitiveness of products. The simplest and most accessible of them are plasma technologies for hardening worn surfaces using electric spark and vibration arc discharges. (Research purpose) The research purpose is studying the possibilities of vibrating plasma technologies for hardening the surfaces of metal products for use in the real sector of the economy, the physical and mechanical properties and structural changes of the surface layer of these products. (Materials and methods) Two batches of samples from 65G steel, widely used for working bodies of agricultural machinery, were processed. One batch consisted of three samples: first sample is initial, second sample with electric spark treatment, third sample was subjected to vibration arc treatment with additional hardening by an electric spark. The morphology of the surface and the elemental composition of the samples were studied using a scanning electron microscope EVO 50 XVP from Zeiss. The microstructure was determined using an inverted metallographic microscope Olympus GX51 with magnification from 50 to 1000x. (Results and discussion). Vibrating plasma methods allow nanostructuring of the surface layer of metal products with the introduction of a whole list of alloying elements of carbide materials into the structure of the surface layer of the product, carburization of this layer and the creation of a hardened layer consisting of oxides, carbides, borides and nitrides. In the process of vibrating plasma treatment, a hardened zone of the surface layer with mixed elements of the base and filler material and a zone of thermal influence are formed in the surface layer of the sample. (Conclusions) The surface layer formed during vibrating plasma treatment is a new nanostructured composite structure. The upper thin layer consists of the anode material modified by elements of the cathode material and the interelectrode medium. Under the upper layer there is a modified hardened layer consisting of a mixture of anode and cathode materials.