Molybdenum disulphide basic

There are basically three ways in which transfer of molybdenum disulphide can be deliberately used for lubrication. These are the pre-coating of a bearing surface with a molybdenum disulphide film, transfer from one bearing surface to an uncoated counterface, and continuing replenishment from a reservoir during machine operation. 

There are basically seven different ways in which molybdenum disulphide can be used alone, namely as a free powder, dispersed in a liquid, as a compact, by in situ formation, as a burnished film, as a transfer film or in a sputtered film. Some... 

More complex ceramic binders have been used, but in general the detailed composition of the binder has not been described. One very complex one consisting basically of molybdenum disulphide in silica, had the composition in Table 11.4. Molybdenum disulphide has also been incorporated in fused-fluoride lubricant coatings to improve their properties at temperatures below 500°C. In tests over 450°C in air the molybdenum disulphide was effective for one test, but was then no longer available because of oxidation. However, such coatings would presumably have useful lives at high temperature in vacuum or inert atmosphere. 

Early attempts to overcome this problem included the addition of hygroscopic compounds, liquid lubricants, metal halides and solid lubricants, including PTFE and molybdenum disulphide ° to the carbon to provide lubrication. However, one of the basic reasons for using carbon for brushes is its good lubricant properties, so that when these are lost and must be supplemented by the addition of solid lubricants, there is no dominant reason for continuing to use carbon. 

This is now a specialized area of product development a wide range of formulations has been derived from the small family of basic engineering plastics. The principal additives are the reinforcing fibres (glass, carbon, aramid, etc.), and lubricants such as PTFE, silicone, graphite and molybdenum disulphide, each of which makes a specific contribution. 

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