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.