What are solid lubricants

Solid lubricants, which are greasy to the touch, are highly anisotropic solids with a low shear strength in at least one dimension. Solid lubricants fall into three main classes - inorganic solids with a lamellar (layer-Uke) crystal structure, solids that suffer plastic deformation easily and polymers in which the constituent chains can slip past each other in an unrestricted way. The categories of most importance are layer structures and soft inorganic compounds. 

Both graphite and molybdenum disulphide oxidise at higher temperatures in air, and the main alternatives used are soft inorganic fluorides. Like many ceramics, although they show brittleness at 

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