Molybdenum Disulfide (MoS2) 

Molybdenum was not discovered until the latter part of the 18th century, and does not occur in the metallic form in nature. Molybdenum remained a laboratory curiosity throughout most of the 19th century until the technology for the extraction of commercial quantities became practical.  It was quickly noted that molybdenum was an effective replacement for tungsten in numerous steel alloying applications because its density is only slightly more than half that of tungsten. MoS2 occurs naturally in the form of thin solid veins within granite. It is mined and highly refined to achieve purity suitable for lubricants. MoS2 has a hexagonal crystalline structure.   The intrinsic property of easy shear occurs at the interface between the sulfur molecules. The interaction between layers provides an effect similar to what a person may experience if trying to maneuver across a floor completely covered with brand new playing cards. Each playing card slides easily with respect to each individual layer. As the total surface resistance is reduced or redistributed among many other interacting surfaces, the net effect is reduced total surface friction and resistance.

Graphite
 
Graphite is a soft, crystalline form of carbon. It is gray to black, opaque, has a metallic luster, and is flexible but not elastic. Graphite occurs naturally in metamorphic rocks such as marble, schist and gneiss. It exhibits the properties of a metal and a nonmetal, which makes it suitable for many industrial applications. The metallic properties include thermal and electrical conductivity. The nonmetallic properties include inertness, high thermal resistance and lubricity. Graphite is a layer lattice lamella crystal structure where the bonds between the carbon atoms in the crystal structure of the layer are stronger than the carbon bonds between layers. Graphite is comprised of carbon and water vapor. Graphite has excellent lubricating properties, as long as moisture vapor is available, and will function as a lubricant up to approximately 1450°F, and as a release and antiseize up to about 2400°F. The oxidation product is CO2. Due to the requirement for entrained moisture vapor, graphite does not function well as a lubricant in a hard vacuum and is therefore seldom used in deep-space applications. Graphite blends and pure graphite dry film lubricant systems are commonly used  many industrial applications.