Henry, I was referring to using graphite in liquid methane and other
fuel/non oxidizer applications, vacuum wasn't specified.
But Teflon/PTFE and other relare fluorinated elastomers have been
aforementioned and are suitable for light loading applications
with glass filled for moderate loading.
MoS2 is messy and never used for LOx service.
Ken
On Sun, Feb 19, 2023 at 1:08 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sun, 19 Feb 2023, roxanna Mason wrote:
All greases are solid at LOx temps, you need teflon or Kel-F bearing
surfaces. Otherwise Krytox, Fluorolube,etc. for more modest temps.
Graphite for liquid methane and other non oxidizer cryo service.
Caution: graphite is often not a good choice for lubrication in extreme
conditions. For example, it's useless in vacuum, because the vacuum
strips off its adsorbed water... and without that, graphite is an
abrasive!
Molybdenum disulfide, superficially similar, *does* work as a lubricant in
vacuum, and hmm, it seems to be considered LOX-compatible too (says here
to look for "Molykote type Z" or some types of "Oxylube" -- caution, my
source on this is old).
Henry