Structure, and Mechanical and Tribological Properties of Ti-Cr-C-Ni-Fe Composite Coatings

The paper analyzes the structure, and the mechanical and tribological properties of Ti-Cr-C-Ni-Fe coatings formed on R6M5 high-speed steel in four modes of electrospark deposition (ESD) using TiC-NiCr electrodes manufactured by extrusion in combination with self-propagating high-temperature synthesis (SHS). The analysis shows that the coatings formed in the four ESD modes at a discharge energy of 0.2, 0.3, 0.6, and 1.0 J are composed mainly of Cr-Ni-Fe-C-solid and Fe0.7Ni0.3 matrix phases strengthened with Ti0.8Cr0.2C particles the size of which decreases to less than 100 nm in going from the coating surface to the substrate. In the SHS electrode during the deposition, most carbide particles are melted. Increasing the discharge energy increases the fraction of solid grains transferred to the substrate by a factor of up to 9. The dependences of the total anode mass loss and total cathode mass gain on the ESD time in the four modes have a classical form. Also considered are the discharge energy dependences of the SHS electrode transfer coefficient, coating run-in length, and wear of the coating and counterbody. The coating hardness measures 10.6-13.5 GPa.