Nanocomposites and nanomaterials

Effect of electrolysis conditions on the composition and structure of the Со-W(WО2)-ТіО2 composite coatings
Yermolenko I.Yu.1, Saray V.V.1, Tur Yu.I.1, 
Sakhnenko N.D.1, Karakurkchi H.V.2
1National Technical University «Kharkov Polytechnic Institute», 
2 Kyrpychova St., Kharkov-61002, Ukraine.
E-mail: kirilesha72@gmail.com
2National Defense University of Ukraine named after Ivan Cherniakhovskyi, 
28, Povitroflotskyi Ave., Kyiv-03049, Ukraine

The results of studies of the influence of the electrolysis regimes and condition on the Со-W(WО2)-ТіО2-coatings composition and structure are discusses. 
The Со-W(WО2)-ТіО2 coatings were formed onto a mild steel substrate from citrate electrolyte by direct current. The coatings composition was determined by EDS on an Oxford INCA Energy 350 electron probe microanalysis. The surface morphology and topography was examined by an atomic force microscopy. 
Stirring allows provides the working solution in a suspension state and uniform distribution of the dispersed phase in the volume of the electrolyte, which provides an increase in the content of ТіО2 in the coating. It is shown that the best conditions for the incorporation of ТіО2 into the coating metal matrix, and tungsten in the form of variable valence oxides are created at a current density of 1.5 – 2.5 A/dm2, temperature 45 – 50°C and at electrolyte stirring up to 100 rpm. More intensive mixing of the working solution causes a decrease in the tungsten content in the coating to 4 at.% due to the peculiarities of the co-deposition mechanism of tungsten with cobalt [1]. In addition, the deposition of dense matte coatings with a mass of up to 6 mg/cm2 and a tungsten content of up to 10 at.% is provide by using an ultrasonic disperser during electrolysis and a current density of 3 A/dm2.
The analyses results of the composition, surface morphology and topography of composites testify to its significant development compared substrate material and allow predicting the high electro catalytic properties of the obtained materials. 

1.	Yermolenko I.Yu., Ved’ M.V., Sakhnenko N.D. The kinetics peculiarities and the electrolysis regime effect on the morphology and phase composition of Fe-Co-W(Mo) coatings / Chapter 28: In: Fesenko O., Yatsenko L. (eds) Nanocomposites, Nanostructures, and Their Applications. NANO 2018. Springer Proceedings in Physics. Vol 221. Springer, Cham, Switzerland AG 2019. P. 403‒423.