Ni‐Doped MoS<sub>2</sub> Dry Film Lubricant Life
Azhar Vellore, Sergio Romero Garcia, Nicholas Walters, D. A. Johnson, Andrew Kennett, Matthew Heverly, Ashlie Martini
Abstract
Abstract The wear life of undoped and Ni‐doped MoS 2 is evaluated at application‐relevant pressure and speed conditions in air. It is found that the Ni‐doped coatings outperform the undoped coatings, particularly at lower pressure (faster speed) conditions. To understand this, the evolution of the coatings during run‐in is characterized in terms of wear track depth, material composition, and microstructure. It is found that wear depth exceeds the thickness of the coatings after hundreds of cycles, in sharp contrast to the wear life that is measured to be tens of thousands of cycles based on friction. This suggests that sliding is facilitated by MoS 2 continually worn from the sides of the wear track for most of the coating life. Further, microstructural analysis shows that the improved performance of Ni‐doped coatings is attributable to cracking and delamination during the run‐in stage, leading to more lubricious material available to facilitate sliding.