Tribological Performance and Coating Characteristics of Sputter-Deposited Ti-Doped MoS2 in Rolling and Sliding Contact

In this work, the tribological behavior of Ti-containing MoS2 film is studied under sliding and rolling contacts. Ti-MoS2 films deposited on AISI 52100 and M50 specimens contain similar to 16 at% Ti are slightly substoichiometric in sulfur and have an amorphous structure. Experiments show that the friction and wear performance of Ti-MoS2 films is influenced by humidity and temperature. For the first time, the rolling contact performance of Ti-MoS2 films was evaluated using a thrust bearing tribometer and ball-on-rod tribometers at similar to 1 GPa Hertzian contact stress. Rolling contact measurements performed in humid air indicate that the useful life of Ti-MoS2 as a solid lubricant depends upon the amount of coating material retained in the contacts. Results of the rolling contact experiments performed in a vacuum indicate that Ti-MoS2 film on balls may function extremely well as a solid lubricant for ball bearings operating in vacuum.