Nanocomposites and nanomaterials

Corrosion resistance of nanostructured titanium coatings deposited by cathodic arc evaporation
Podhurska V.Ya.1, Ostash O.P.1, Ivashkiv V.R.1, Kuprin A.S.2, Rostova H.Yu.2, Kovtun Yu.V.2, Sayenko S.Yu.2
1 Department of Hydrogen Technologies and Alternative Energy Materials, Karpenko Physico-Mechanical Institute of the NAS of Ukraine, 5 Naukova str., Lviv 79060, Ukraine.
E-mail: podhurskavika@gmail.com
2 National Science Center Kharkiv Institute of Physics and Technology, 1 Akademicheskaya str., Kharkiv 61108, Ukraine.

Hard chromium coatings are one of the most used anticorrosion coatings but are produced from chromic acid solutions containing chromium in the hexavalent state and several catalytic anions that are known to be carcinogenic [1]. The research into alternative processes to chromium plating is focused on finding new surface technologies based on more environmentally friendly processes. Cathodic arc evaporation PVD process has outstanding potential to deposit corrosion-resistant coatings with relatively dense structure [2]. Titanium and titanium alloys are widely used for corrosion protection because they offer high chemical resistance against various corrosive media due to a dense self-sealing oxide layer [3].
Titanium coatings have been deposited on steel substrates in a cathodic arc system. Variable parameters of the deposition process were the negative potential on the substrate Ub = -50...-200 V. The corrosion behaviours of coated samples were electrochemically characterized with voltamperometric measurements in 3% NaCl water solution. It is shown that titanium coatings represent nanostructure, high microhardness (4 GPa) and corrosion resistance depending on the magnitude of the bias potential on the substrate.

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