Tribological behavior of Ni-based composite coatings produced by cold spray

The current experiment examined the friction and wear characteristics of Ni-based composite coatings developed by cold spray route. In the developed coatings, fixed concentration of MoS2 (10 wt. %) and varying concentrations of Ag (5, 10, and 15 wt. %) were incorporated to evaluate the lubricating potential of reinforcing elements. The specimens were slid in various working regimes of loads (6, 11, 16, & 21 N) and at a fixed sliding speed of 0.3 m/s under room temperature (RT). According to the investigation, all participating composite coatings have revealed a lower coefficient of friction (COF) and wear rate as the testing load increased from 6 to 16 N, beyond which a reverse trend was recorded till 21 N. However, composite coating with 10 wt. % Ag has shown excellent tribological properties in terms of the lowest COF (0.29) as well as wear rate (4.0 x 10-5 mm3/Nm) at 16 N and 0.3 m/s. The superior tribological characteristics of the aforesaid coating have been explained and well connected to the synergistic effect of solid lubricants (Ag and MoS2) as well as the optimal weight percent of Ag in the creation of tribo layer on the wear track.