Veselivska H. Corrosion and corrosion-mechanical durability of titanium alloys, surface modified with nitrogen using ion-plasma technologies.

Titanium alloys of different structural-phase composition, surface modified by nitrogen ion implantation and coatings with titanium nitride are the investigation object. The goal of the work is to determine the effect of modifying of titanium alloys surface layers on their corrosion-electrochemical and corrosion-mechanical behaviour in environments of different aggressiveness. For 30 keV ion energy the dependence of corrosion resistance of ion-implanted titanium alloys on the irradiation doses is found. The effective activation energy of the corrosion process and anodic dissolution of nitrogen ion-implanted alloys and titanium nitride coatings in neutral solutions was calculated at temperatures 20...70 С. It was established that their velocity is determined by the diffusion processes at the phase interface. It was found that the most aggressive medium for the non-treated titanium alloys is highly concentrated solution of sulfuric acid (10...80%) while for the modified ones - chloride acid (10...20%). The stabilized value of the electrode potentials in the working zone of TC-5 and BT-6 alloys after different treatments, which can be used for prediction of the corrosion-abrasive layer-by-layer wear of alloys and their serviceability of the trybocorrosion conditions was found.