Nanocomposites and nanomaterials

Synthesis of multicomponent metal and carbon coatings by modified magnetron sputtering of a rod-like target
Kosminska Yu.O., Perekrestov V.I., Dyoshin B.V.
Department of Nanoelectronics, Sumy State University, R.-Korsakova 2, Sumy 40007, Ukraine. 
E-mail: y.kosminska@phe.sumdu.edu.ua

Multicomponent coatings based on high-entropy alloys and their nitrides, carbides, etc. are of increasing research interest because of their promising mechanical and protective properties for various applications. In this work we develop new experimental technique for producing the mentioned multicomponent coatings on inner surfaces of low diameter pipes and similar systems.
The offered technique uses specially modified magnetron sputterer combined with cylindrical hollow cathode and rod-like composite target [1]. When depositing multicomponent high-entropy alloy coatings by magnetron sputtering, a single target is usually used which is sintered from all the components prior to deposition. Additionally, one or two components can also be sputtered from separate one-element targets. In contrast to these common variants, in our case the target can be implemented as a rod composed of one-element discs located along the central axis of the device. The rod is sputtered uniformly in radial directions. By varying elemental composition of the discs, their size and sequence in the rod, the needed composition of the coating can be easily achieved. By sliding the outer deposition surface (a pipe) along the central rod target, layered composite structures can be also obtained. Thus, by means of the described sputterer, (CrCoNiFeTi)C coatings with chromium underlayer have been produced and characterized. Mostly the coatings have highly dispersed structure with crystallites a few nm in size. With increase in carbon content, the microhardness rises to 27 GPa, carbide phases appear, and surface roughness considerably decreases.
To estimate the elemental composition distribution, the mathematical model has been developed which describes mass transfer of the sputtered materials and takes into account the geometry of the system, rod-like target configuration, cosine angular distribution of sputtered atoms and their scattering on the working gas.

1.	Kosminska Yu.O., Perekrestov V.I., Kornyushchenko G.S. Calculation of elemental composition distribution of multicomponent metallic coatings deposited onto inner surfaces of low diameter pipes // Metallofiz Nov Tekh+.-2019.-41. (in press)