Molybdenum Disulfide as a Lubricant And Catalyst in Adaptive Nanocomposite Coatings (Preprint)

摘要

Nanocomposite YSZ-Ag-Mo-MoS2 with different MoS2 additions (0-100 atomic percent) coatings were deposited with a hybrid pulsed laser/magnetron sputtering/filtered cathodic arc process. Wear testing was performed from 25- 700 degrees C for each of the coatings. Electron microscopy and other characterization techniques were used to examine the surfaces and wear tracks of the coatings to determine the mechanisms resulting in the measured tribological properties. Adaptive coatings containing 8 atomic percent MoS2 demonstrated a friction coefficient of 0.2 throughout the temperature range examined here, compared to 0.4 for YSZ-Ag-Mo with no MoS2. Characterization of the YSZ-Ag-Mo-8%MoS2 coating revealed that MoS2 and silver provided lubrication at temperatures less or equal 300 degrees C, while silver molybdate phases and MoO3 were lubricious at higher temperatures. Silver molybdate was not observed in the coatings containing 0% MoS2. The role of sulfur in the formation of silver molybdate is briefly discussed.