Dry-Film Lubricants from Molybdenum Disulfide Bonded with Microfibrous Boehmite

摘要

Binders that have been tried for powdered lamellar dry lubricants have short-comings such as hindering the realignment of the lubricant particles or encapsulating the lubricant, making a wearing-in process necessary. A microfibrous form of colloidal alumina (boehmite) is shown to act as a superior nonencapsulating binder for molybdenum disulfide in the formation of dry lubricant films. Such films exhibit lower coefficients of friction than have been reported for molybdenum disulfide or graphite films bonded with any other material. These new lubricating coatings have good load-carrying ability and durability at any temperature below the decomposition temperature of molybdenum disulfide (700 F). Optimum performance of these boehmite-bonded films is obtained when (a) the ratio of fibrillar boehmite to MoS2 is near 0.20, (b) the film is 0.2 to 0.5 mil thick, (c) the substrate is hard and highly polished, and (d) the film is applied as an alkaline dispersion (pH = 10) and then dehydrated by baking at 550 F. (Author)