Ambient and nitrogen environment friction data for various materials and surface treatments for space applications

A multivariate tribological evaluation of candidate materials, surface
treatments and dry film lubricants is necessary for design of moving
mechanical components that function reliably in extreme conditions,
including for long duration space missions. In this study, linear
reciprocating or unidirectional sliding friction data was collected using
ball-on-flat tests. The balls were hardened 440C stainless steel (either
uncoated or sputtered with MoS2) and flat surfaces were 440C stainless
steel, Nitronic 60 stainless steel or Ti6Al4V titanium alloy with various
surface treatments and/or dry film lubricants. Surface treatments included
anodizing, nitriding and electrical discharge machining. The dry film
lubricants included Microseal 200-1 , sputtered MoS2  and a
nano-composite coating i-Kote. The data contains applied normal load,
measured friction force, calculated coefficient of friction, ball
position, ambient temperature and relative humidity during testing. Tests
were performed at different peak Hertzian contact pressure conditions
ranging from 300 MPa to 2000 MPa. Data is also available for flat surfaces
that were vacuum baked at 150 oC after surface treatment and dry film
coating as well as samples tested in inert gas (nitrogen) environment.
This data can be used both to fundamentally understand the tribological
properties of different material systems as well as to enable design of
components for specific applications, conditions and duty cycles.