Latest Progress of Solid Lubrication Coatings for Fabrication of Gas-Foil Bearings

The latest development of gas-foil bearings, an advanced bearings technology in fabrication of high speed/precision/reliability miniaturized products and comprising housing, elastic bump-foil and smooth top-foil, was tentatively reviewed.The hot-spot research subject is modification, with solid lubrication coatings, of the sliding contact-surfaces involved, that is, in the start-stop stage of hydrodynamic gas-foil bearings, dry friction occurs at the interface of the journal and top-foil.The discussions with specific examples focused on:i) The strengths/weaknesses of the plasma spray (PS) series of solid lubrication materials, including PTFE, MoS₂, PS100…PS304 and PS400; ii) The synthesis techniques of diamond-like-carbon (DLC) coatings; and iii) The advantages/disadvantages of Korolon^TM series of lubrication coating techniques/materials.The existing technical problems, possible solutions, development trends/limitations of theoretical/technological studies of solid lubrication coatings, for gas-foil bearings, were also briefly discussed in a thought provoking way.