Gordiienko V. Electrodeposition of nanocrystalline chromium-carbon coatings from solutions of chromium(III) salts

The object of investigation - electrolytic coating of chromium alloys with electrolytes based on salts of Cr(III). The purpose of investigation - development of scientific bases of modern high intensity environmentally safe technology for thick nanocrystalline coating alloy chromium-carbon of electrolytes based on salts of Cr(III). Methods of investigation: voltammetry and gravimetry, potentiometry, photokolorymetry, XPS, GDS, X-ray diffraction analysis, the method of small angle X-ray diffraction, measurement of microhardness of coatings, tribotechnical measurements, optical microscopy and scanning electron microscopy. Theoretical and practical results - the first time received systematic set of experimental data on the influence of various factors on the electrodeposition of the alloy chromium-carbon with electrolyte based on trivalent chromium with the addition of urea and formic acid. Novelty: a new mechanism of chromium-carbon alloy is proposed whereby the reaction deposition of chromium impose their kinetic regularities of coprecipitation carbon in the alloy, and the inclusion of carbon in the sediment carried by the mechanism of chemical interaction of highactive Cr atoms adsorbed on organic particles. Ability to produce high quality nanocrystalline chromium-carbon coatings (containing carbon ~ 10%) with a thickness of several hundred micrometers and given the size nanokrystalitiv (3.5 nm) of solutions of salts of trivalent chromium in the presence of urea and formic acid. The experimental results on the effects of electrolyte and electrolysis mode to output at current, deposition rate and the composition and properties of formed coatings is the basis of new environmentally sound technologies of high deposition thick (several hundred micrometers) nanocrystalline coatings based on chromium with predictable properties. The new technology of electrodeposition alloy Cr-C using an electrolyte containing trivalent chromium sulfate basic (chromic tannin), which allows you to significantly increase the cover ability of the electrolyte (in comparison with the known prototypes) and obtain thick nanocrystalline coating alloy chromium-carbon containing carbon ~ 10% (mas.), output current by 36% and the rate of deposition of ~ 0.7 mm / min (at current density 20 A/dm2). Scope: in engineering and aerospace areas of industrial production.