Nenastina T. Cobalt and Refractory Metal-Based Electrolytic Alloys and Composites for Eco-and Energy Technologies

The object of research is chemical reactions in the electrolyte and electrochemical processes that occur at the phase interface during the co-deposition of cobalt in combination with tungsten, molybdenum and zirconium to the alloy or composite coatings. The subject of research is the mechanisms and technological parameters of the cathode deposition of cobalt–based coatings with refractory metals from complex polyligand electrolytes and the functional properties of obtained coatings. The purpose of the study is devoted to the development of the scientific bases for electrolytic alloys and composites that are based on cobalt with refractory metals and are intended for eco- and energy technologies. Research methods ‒ voltammetry, energy dispersion X-ray spectrometry, scanning electron microscopy, scanning probe microscopy, X-ray diffractometry, electrode impedance spectroscopy. Theoretical and practical results – a mechanism of the codeposition of the metals to Со-Mo-W/Со-Mo-WOx, Сo-Мо-Zr/Сo-Мо-ZrO2, Сo-W-Zr/Сo-W-ZrO2 coatings was substantiated as an aggregate of consecutive and conjugated reactions with participation of mono- and biligand complexes and hydrogen ad-atoms and the generalized chart has been suggested. It was proved that it is quite possible to control the composition and the structure of the multicomponent cobalt-based coatings by varying the electrolyte composition and also by using direct or unipolar pulse current of the varied current density. The variadic process flow diagram was developed for the electrodeposition of the alloys and composites that are based on cobalt with refractory metals that enable the deposition of the thin-film materials for the intended purpose and synergetic materials with the comprehensive realization of improved physical-mechanical and physical-chemical properties in surface layers. The novelty – The hypothesis of the deposition of nanocomposite multicomponent coatings with the strengthening phase from electrolyte solutions was experimentally proved. This strengthening phase is formed in situ throughout the electrode process and due to this fact it is uniformly distributed in the growing coating layer. The effects of the electrolyte composition and electrolysis conditions on the elemental and phase composition and also on the surface morphology of obtained coatings have been defined. The realization degree consist of the laboratory samples and experimental items with developed coatings pilot test at the enterprises of JSC «Kharkiv Tractor Plant» and LTD “SPF LCB HM”. The branch of this research application is the technical process of electrochemical production, Research Studies Institutes and а educational process.