Following the pioneering work of Prof. James Lauer, the ability to provide continuous solid lubrication through vapor phase delivery of carbonaceous gases has been successfully demonstrated on a pin-on-disk contact at the temperatures of 650 C. Results from tribological experiments under 2 N normal load and 50 mm/s sliding speed showed an over 209 reduction in friction coefficient. The samples were silicon nitride (pin) versus CMSX-4 (disk) and the experiments when run in a nitrogen environment with an acetylene admixtures. Two repeat experiments gave average friction coefficients of µ = 0.03 and µ = 0.02. The process was robust and provided low friction for the entire 500 m of sliding. Using focused ion- beam milling, high-resolution transmission electron microscopy, and confocal Raman spectroscopy, the resulting solid lubricant was found to be oriented microcrystalline graphite.

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Special Issue of Tribology Letter