I can use any two of the list below for a medium-duty sliding bearing in an
agressive oxygen environment (3,000 psi and ~200C).

Keeping cost and availability in mind, which would be the best pair to use
both as a low-friction bearing and to avoid galling (the cheapest and most
available pair which would work reliably would probably be the best choice)?

Imagine a 6 mm shaft in a plain unlubricated bearing, under light-to-medium
load and low speed.


I don't know much about choosing metals, there may be an obvious choice or
two in there, and if such exists that's what I'd like to know - please don't
omit the simple answers, I am a newbie at this!

Quantities involved are small, so availability of small quantities at
reasonable rates is more important than raw cast.


Brass (any)
Tin Bronze (but not Aluminium Bronze)
Nickel 200
Copper 102
Beryllium Copper
Monel 400
Monel K-500
Silver
Inconel
MA-754
Haynes 188
Haynes 242

This selection is from the G4/NASA/ASTM manual 36 - I haven't heard of some
of them before.

Some ceramics would be okay chemically too, for instance Alumina, Silica and
Zirconia would be, and probably Macor, but I don't know if they would be
strong enough. I know very little about engineering ceramics, any help would
be appreciated.



Thanks,


--
Peter Fairbrother