Some Commercial Molybdenum Disulphide Greases

Molykote 165LT Molykote FBI80 Mineral oil, bentonite thickener. 

Molykote 1121 Molypaul Grade 1110 Molypaul Easymesh Molypaul Thermo-Paul 1 and 2 Rocol MG Rocol Sapphire Hi-Load 2 Rocol MTS 1000 Molykote 1132 Synthetic oil, inorganic 

Molypaul Molyrace HT Aeroshell Grease 17 Molykote ET 300 Aeroshell Grease 15 Rocol MX 33,44,66,550 Silicone oil base 

Fowle ° has pointed out the potential for molybdenum disulphide to reduce wire-wool failures of plain bearings. This type of failure can occur when a hardened adhesive wear particle becomes embedded in a relatively soft bush, causing severe abrasive wear of the counterface. The formation of the initial wear particle can arise from a transient failure of the hydrodynamic lubricant film, caused, for example by temporary interruption of a drip feed or coolant flow. Addition of a small amount of molybdenum disulphide, say 3% or more, to the lubricant can prevent the short-term occurrence of adhesive wear, and thus the formation of the initiating particle. 

Dispersions have previously been described in Chapter 9 in the context of volatile liquids designed to supply powder to a system. But dispersions in non-volatile liquids are also used as a means of feeding a high concentration of molybdenum disulphide into a system while still maintaining some degree of flow. 

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Table 13.9 Some Commercial Molybdenum Disulphide Greases (Some of these may now be obsolete)...

Table 13.9 lists some of the many commercial molybdenum disulphide greases. 13.4 PASTES AND DISPERSIONS... 

The implication of this work is that the presence of a burnished film on a metal surface should help to improve lubrication by a mineral oil, especially where there might otherwise be some tendency for partial oil starvation. It should be remembered, however, that this film was produced by burnishing molybdenum disulphide powder. Commercial dispersions, bonded films, composites or greases, as well as fully formulated lubricating oils all contain other substances which may significantly affect wetting behaviour. 

Some commercial greases have also been produced which are based on a perfluorinated polyether oil with added molybdenum disulphide. They can be used for even higher temperatures than the silicone-based greases, but are much more expensive and would normally only be used on small components. They have the further advantage of excellent resistance to chemical attack. 

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