In the era of modern technology, tribo coupling components require efficient lubrication to ensure optimal performance, and to avoid significant material loss throughout the entire duty cycle. Solid lubricants, when reinforced with optimal contents, have shown the ability to improve the tribological performance and sustain the lubricious behavior over extended periods. The goal of this study is to improve the reliability and lifetime of tribo components used in a variety of industrial applications. The investigation explores the lubrication mechanisms, and optimizes the tribological behavior of the Ni-based alloy coating impregnated with molybdenum disulfide (MoS2) and varying contents of silver (Ag). Specifically, four compositions containing 7 wt.% MoS2 with different contents of Ag, i.e., 5, 10, 15, and 20 wt.%, were developed via the HVOF route and tested from room temperature (RT) to 800 °C. The optimal composition was determined using a parametric experimental optimization approach based on friction and wear minimization. In particular, the coating with 15 wt.% Ag showed the least friction and wear across all tested temperatures. The coating material having 15 wt.% Ag along with 7 wt.% MoS2 attained a COF of 0.22 and wear rate of 5.3 × 10−6 mm3/Nm at 800 °C. The optimal content of Ag (15 wt.%) in the coating (NC15) decreased the wear rate by approximately 27% compared to the 20 wt.% Ag variant (NC20) at 800 °C. Overall friction and wear of the derived coatings decreased at 800 °C, with a minor increase at 400 °C. The apparent behavior demonstrated the complex interplay between coating ingredients and testing temperatures. The favorable tribo-chemical reactions and efficient boundary lubrication mechanisms worked together to reduce friction and wear.
Aslam et al. (Thu,) studied this question.