The possibility of combining plasma electrolytic carburizing, polishing and micro-arc oxidation of commercially pure titanium to increase microhardness, wear resistance and quality of the modified surface has been demonstrated. Using X-ray structural analysis methods, structural and phase changes on the surface and in surface layers after processing were studied, solid titanium carbides TiC and TiC were detected in the modified layer, and the diffusion depth of carbon and oxygen was determined. The influence of each of the plasma electrolytic treatment methods on the tribological behavior in a friction pair with structural bearing steel was studied. The lowest surface friction coefficient is observed after carburizing at 900°C, polishing at 250 V and micro-arc oxidation at a current density of 12 A/dm. It was determined that an increase in the loss of mass during friction and the volume of removed material after combined treatment is associated with an increase in the contact area in the tribocoupling, which is confirmed by an increase in the wear of the counterbody. The quality of the modified surface was assessed based on the geometry data on the surface of wear marks, the complex Kragelsky–Kombalov criterion was calculated, and the type of wear was determined. The Kragelsky–Kombalov criterion after plasma-electrolytic treatment decreases by 1.2–1.4 times, which indicates an increase in the bearing capacity of the rough profile of modified samples. The wear mechanism is fatigue wear during plastic deformation of the tribological conjugation.
Tambovskyi et al. (Wed,) studied this question.