Characterization of Lubricative Coating after Exposure Test in Orbit

Abstract

Change in such properties were characterized as tribological properties, surface chemical condition and so on for lubricative coating films of titanium nitride (TiN) that have been effected by exposure to an environment in orbit with the Russian Service Module / Space Environment Exposure Device (SM/SEED) prepared by JAXA on the International Space Station (ISS). Friction measurement with a mating pin of stainless steel showed that TiN coated stainless steel sheets after exposure test to orbit environment for a year generally decrease friction coefficient and can keep almost constant even after bakeout under a vacuum as well as at an atmospheric pressure due to some kind of modification of lubricant layer by the exposure.