High vacuum tribometry tests, employing the ball on flat contact geometry, are being conducted for bearing steels (e.g. 440C) lubricated with low vapor pressure fluid lubricants used in spacecraft reaction wheel assemblies (RWA) and control moment gyroscope (CMG) bearings. The impetus for this work is to gain insight into whether or not such tribological systems have a propensity to develop a starved contact; through either interfacial interactions (dewetting) or adlayer fluid entrainment barriers. To date, tribometry tests have shown that decomposition of Pennzane based lubricants results in polymeric materials depositing adjacent to the contact on both the steel ball and flat. Unexpectedly, on both surfaces the deposited adlayers were found to exhibit a distinct deposition pattern that is anticipated to reflect the lubricants reflow field within the meniscus. Adlayer thickness measurements and the use of an N2 blow off jet to qualitatively examine the local adlayer-lubricant interaction will also be discussed.

High vacuum tribometry tests of fluid lubricants on bearing steels

248th National Meeting (2014)

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