Characterization of Titanium Dioxide Coatings Obtained by Vacuum-arc Deposition Anton Taran 1 , Igor Garkusha 1,4 , Alexander Timoshenko 1 , Valerij Taran 1 , Ivan Misiruk 1 , Tamara Skoblo 2 , Svetlana Romaniuk 2 , Taras Maltsev 2 , Vadym Starikov 3 , Alexey Baturin 3 , Yurij Gnidenko 4 1 National Science Center “Kharkov Institute of Physics and Technology” (NSC KIPT), Institute of Plasma Physics, Kharkov, Ukraine 2 National Technical University of Agriculture, Kharkov, Ukraine 3 National Technical University “Kharkov Polytechnical Institute”,Kharkov, Ukraine 4 Karazin State University, Kharkov, Ukraine Email: avtaran@ukr.net Abstract. TiO2 coatings on AISI 430 stainless steel were produced by the vacuum-arc deposition technique with the application of modified curvilinear magnetic filter allowed enhanced deposition rates up to 50 µm/ hour decreasing the amount of macroparticles. The structure, chemical and phase composition of the obtained coatings was investigated using SEM with EDX, XRF and XRD analysis. According to X-ray diffraction analysis, the formation of stoichiometric TiO2 phase took place. The mechanical and tribological properties were established. The obtained coatings had average nanohardness of 13.8 GPa and Young’s modulus of 211 GPa. Dry friction wear tests revealed high resistance of the coating to wear showing low friction coefficient under a load of 50 N. The statistical results of photo-catalytic activity showed a significant decrease of E.coli colonies on samples coated with TiO2 during 20 min UV exposure format. Keywords: Titanium dioxide, structure, vacuum-arc deposition, coating, phase composition, nanohardness, photocatalytic activity 1 Introduction Titanium dioxide TiO 2 has many potential applications as a coating including medical technology; wear protection, due to non-toxicity, high photocatalytic activity, and strong self-cleaning ability [1]. Titanium dioxide is a well-known photocatalyst in presence of UV light. A substantial amount of literature has been published on the effect of photocatalytic TiO 2 nanoparticles on microorganisms [2,3]. According to the literature data TiO 2 on stainless steel reduces bacterial activity of E.coli by 99 %. This provides an effective antimicrobial surface coating method for medical implements thereby reducing the risk of hospital-acquired infections [4]. The efficiency of photocatalytic disinfection is attributed to the oxidative damage mainly induced by reactive oxygen species (ROS), such as O 2 -, H 2 O 2 and HO-. These reactive oxygen species are produced by redox reactions between adsorbed species (such as water and oxygen) and electrons and holes photo-generated by the illumination of TiO 2 . TiO 2 films were prepared by various methods, such as chemical vapor deposition, pulsed laser deposition, sol-gel deposition, spray pyrolysis; plasma enhanced chemical vapor deposition and DC/RF magnetron sputtering [5-9]. It is well known that the method of vacuum-arc deposition provides a wide variation of the microstructure and hardness of coatings by changing the grain size, crystallographic orientation, lattice defects, texture, as well as surface morphology and phase composition [10-14]. The factors that have limited the applications of PVD coatings as complete barriers to corrosion are the presence of coating defects such as pinholes, voids, cracks and macro-particles. In so doing, a new source of filtered vacuum arc plasma was used providing transportation to the condensation surface of at least 60% of the current of ions emitted by cathode spots. This is 1.5 times higher than that of known analogues. Deposition rate reaches several tens of microns per hour that is comparable to traditional sources of unfiltered plasma. The area occupied by macroparticles is less than 0.2% of total area of coating per 1 m of its thickness. Journal of Advances in Applied Physics, Vol. 2, No. 1, February 2020 https://dx.doi.org/10.22606/jaap.2020.21001 1 Copyright © 2020 Isaac Scientific Publishing JAAP