Nanostructured surfaces

The influence of PEO-modes on morphology and composition of doped nanocomposites
Karakurkchi A.V.1, Sakhnenko M.D.2, Korogodskaya A.M.2, 
Yermolenko I. Yu.2, Yar-Mukhamedova G.Sh.3
1National Defense University of Ukraine named after Ivan Cherniakhovskyi, Povitroflotskyi Ave. 28, Kyiv-03049, Ukraine. 
E-mail: anyutikukr@gmail.com
2National Technical University “Kharkiv Polytechnic Institute”, Kyrpychova Str. 2, Kharkiv-61002, Ukraine. 
3Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, 050040, Al-Farabi av., 71, Almaty, Kazakhstan.

Plasma-electrolytic oxidation (PEO) of valve metals in alkaline complex electrolytes allows the formation of multifunctional materials (nanocomposites). These materials synergistically combine the characteristic properties of the oxide matrix and auxiliary components [1].
PEO was carried out on the alloy VT1-0 in diphosphate electrolytes with the addition of salts of transition and refractory elements. It is shown that the starting density of oxidation current is the main factor influencing the operating voltage of PEO, which is the main technological parameter of the formation of composite systems. It is established that increasing the operating current density and the use of the “decreasing power” mode allows to accelerate the process of incorporation of the dopant metal into the TiO2 matrix during PEO. It is proved that increasing the oxidation time to 30 minutes contributes to the enrichment of the surface layers of the target component. So, it is possible to flexibly control the process of plasma-electrolyte synthesis of coatings due to the variation of the component composition of the electrolyte and technological parameters (j, U, t). The morphology of the surface layer is transformed from torus-like (characteristic of TiO2) to unevenly rough or globular with increasing content of the additive component. The presence of oxide phases of the base metal (titanium) and oxides of dopant metals in the synthesized coating was established for the studied systems. This, in combination with the results of AFM analysis, allows to position the formed coatings as nanocomposites.

1.	Yar-Mukhamedova G.Sh., Sakhnenko N.D., Ved M.V. Nanocomposite electrolytic coatings with defined functional properties. Almaty: Kazakh University, 2020. 180 p.