Nanostructured surfaces

Morphology and phase composition of nanostructured
PEO-coatings on valve metals
A.V. Karakurkchi, N.D. Sakhnenko, M.V. Ved’, K.B. Bohdanova,
I.I. Stepanova
National Technical University “Kharkiv Polytechnic Institute”, Kyrpychova Str. 2, Kharkiv-61002, Ukraine.
E-mail: anyutikukr@gmail.com

PEO coatings on valve metals, particularly aluminum and titanium, possess catalytic properties and are widely used in the heterogeneous catalysis. But the effectiveness of separate oxides, however, is not high enough. Introduction to the composition of oxide systems TiO2 and Al2O3 additional components increases efficiency of the catalytic activity of oxide-metallic systems. Incorporation occur both through direct capture of composite particles from electrolyte in the process of oxide layer growth and at the expense of thermochemical and electrochemical transformations of the working solution's components. 
Oxide coatings were obtained by the method of PEO on valve metals (titanium and aluminum). A nanostructured layer on the samples (Ti and Al alloys) was formed by the PEO method under galvanostatic mode. Current density of the formation was 1‒20 A/dm2, voltage ‒ up to 240 V. Electrochemical treatment was carried out for 30‒60 minutes in alkaline solutions whose composition was introduced with manganese or cobalt cations.
The inclusion of dopants into the composition of the synthesized oxide systems changes surface morphology and phase composition of treated materials. The PEO coatings are formed in nonequilibrium conditions and availability of amorphous halo at the angles of 2θ ~ 20° and the formation of oxides of a different manganese and cobalt oxidation in matrix of TiO2 and Al2O3.
These manganese- and cobalt-containing nanostructured oxide systems could find application in the technology of ecological catalysis for the disposal of toxic components when used in the systems of air and water purification.

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2.	Karakurkchi A., Sakhnenko N., Ved’ M. and etc. Application of oxide-metallic catalysts on valve metals for ecological catalysis // East.-Europ. J Enterpr. Technol.-2017.-5/10 (89).-P. 12-18.