Tribological properties of electrospark-deposited and further laser-hardened coatings

The tribological properties of the coatings based on fine-grained VK6-M hard alloy, chromium, and molybdenum have been investigated. The coatings were obtained by the electrospark deposition followed by the laser treatment. The electric spark deposition does not affect the coefficient of friction and temperature in the friction zone of the coated surface in contrast to steel 45 surface. Additional laser treatment reduces the dispersion of the friction coefficients and temperatures, but hardly alters their level. The wear rate of the coatings increases in the direction VK6-M → Cr → Mo → steel 45. A hard alloy coating is most effective, since the wear rate decreases as much as 15 times compared to steel 45. The wear rate of the coatings based on chromium and molybdenum is 1.7 and 1.4 times lower than that of steel 45. The laser treatment reduces the wear rate even more, i.e., by 70% for the coating based on the hard alloy and 3.5 and 3 times, respectively, for coatings based on chromium and molybdenum.