Tribological and Corrosion Properties of Coatings of Ultradisperse TiB2-TiAl Electrodes with Nanosized Additives Deposited on Ti-Gr2 by Non-Contact Electrospark Deposition

The tribological and corrosion behavior of commercial pure titanium - Ti-Gr2 with coatings obtained by mechanized contactless local electrospark deposition (LESD) with a rotating electrode with low pulse energy and an ultradisperse TiB2-TiAl electrode reinforced with ZrO2 and NbC nanoparticles is investigated in this work. The current research is driven by the need for improved corrosion resistance of titanium surfaces in automotive components, shipbuilding, aviation, aerospace, petrochemical and many other industrial and domestic areas. The work is a continuation of our previous research, in which the correlations between the electrical parameters of the LESD mode and the relief, roughness, thickness, microhardness, composition and structure of the coatings obtained with this electrode were studied and analyzed. In this work, the influence of the pulse parameters of the LESD process (respectively, the roughness, thickness, composition, structure of the coatings) on the coefficient of friction, abrasive and corrosion resistance of the coatings has been studied and their role in simultaneous protection of titanium surfaces from wear and corrosion has been clarified. Coatings with the presence of newly formed wear-resistant phases and crystalline-amorphous structures, with increased hardness up to 13 GPa, low roughness Ra= 1.5 -2.8 μm, thickness up to 20 μm and minimal structural defects have been formed. By comparing the potentiodynamic polarization curves, polarization resistance, electrochemical impedance and tribological characteristics of the coated surfaces, it has been established that their corrosion resistance increases by more than 2 times and their wear resistance during friction increases by 4-5 times compared to those of the substrate. Appropriate pulse parameters have been defined to allow for uniform coatings with reduced roughness and structural defects, with predictable thickness, roughness and hardness, and with maximized corrosion and abrasive wear resistance.