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Molybdenum Disulfide and Its Uses as a Dry Lubricant

by BrianGeranen

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Molybdenum disulfide (MoS2) is an inorganic compound that finds
extensive application as a dry (solid) lubricant. Since this compound
remains largely unaffected by oxygen, high temperatures, magnetic
fields, and dilute acids, it is an ideal lubricant for heavy-duty
operations. This compound is also non-toxic. MoS2 demonstrates low
friction owing to the weak bonding between its layered molecular

This compound is bluish or silver gray in appearance and has a
coefficient of friction that ranges between 0.06 COF to 0.15 COF. The
appearance and feel of MoS2 is similar to that of graphite. However,
MoS2 provides significantly higher lubricating performance than
graphite. MoS2 works several times more effectively than graphite even
in vacuum environments. While graphite requires an external source of
moisture, MoS2 achieves peak performance in the absence of water vapor.

What is a dry film lubricant ?

These lubricants are also referred to as a solid film lubricant or a
dry lubricant. As the name implies, this lubricant is used in a solid
state. It is different from a liquid lubricant both physically and
operationally. Apart from MoS2, materials such as tungsten disulfide and
graphite are widely used as dry lubricants. Here are two common
scenarios where one might need to opt for dry lubricants:

  • Certain machines and systems, once installed, have several
    hard-to-reach areas that cannot be accessed for regular lubrication. Dry
    lubricants provide long-term reduction in friction and wear in such
  • Liquid lubricants often fail in extreme environments exposed to
    high temperatures, vacuum, or extreme pressure. Dry lubricants such as
    tungsten disulfide and molybdenum disulfide remain largely unaffected in such environments and continue to provide the desired lubrication performance.

Using molybdenum disulfide as a solid film lubricant

This lubricant can be applied to the desired substrate using several
different methods. Some of the most common ways of applying MoS2 low
friction coatings to the surface of a substrate are:

  • Spraying
  • Physical vapor deposition
  • Rubbing and burnishing
  • Impingement with or without inorganic binders
  • Dipping (carried out using a paint-like substance comprising MoS2)

If applied at ambient temperature, it requires no curing time. There
are several standard specifications that determine the application of
solid film lubricants. MoS2, for instance, could be applied in
accordance with MIL-PRF-46010 and AS5272 and similar to AMS2526.

The performance of MoS2 as a dry film lubricant
would depend on external factors such as: humidity levels, sliding
conditions of the application, purity of the application, speed of
movement and so on.

Applications of molybdenum disulfide

There are a myriad of applications where MoS2 is considered to be a
reliable dry lubricant. These include chain saws, pilot valves, engine
and drive train parts, compressors, rheostats, cryogenic pumps, slide
mechanisms, bearings, gears, fasteners and magnetic heads among many

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