| 摘要 |
A foil element (16) for a high-speed fluid-film-lubricated foil bearing (10) is given a dry lubricating coating (22) on its rubbing contact surface (20) by the method of applying a plurality of successive sub-coatings (24,26,28; 32,34,36; 40,42,44) of a coating mixture of graphite fluoride powder (e.g. CF1.0), polyimide varnish, a thinning liquid and a small quantity of wetting agent. Each sub-coat (24 etc) in turn is individually cured at a temperature of 107 DEG -135 DEG C before the next succeeding sub-coat is applied and the outer surfaces of selected sub-coats, for example, every third sub-coat (28,36) out of a total of nine are individually deroughened by sandpapering after curing. The resultant multi-layer coating (22) is then cured by exposure to an initial temperature of 100 DEG C which is gradually raised to a final curing temperature of 343 DEG -399 DEG C and maintained for an hour. Thereafter dry CF1.0 powder is burnished into the outer surface (44) of the cured multilayer coating (22) and the burnished surface (48) is deroughened to reduce the overall thickness of the multilayer coating (22) to a predetermined final value, e.g. 25. 4 mu m. The resultant coated foil member has a greatly improved surface smoothness and thickness uniformity rendering it suitable for use in high-speed gas-film-lubricated bearings having rotational speeds in excess of 100,000 RPM and accompanying high operating temperatures. |
