3. Solid lubricants

These are solid compounds that are easily sheared by friction, due to :

• of a lamellar structure: graphite, molybdenum disulfide (MoS ₂ ), graphite fluoride (CF _x ), boron nitride (BN), etc. ;

• a polymeric structure with a long oriented straight chain: polytetrafluoroethylene (PTFE), polyamides, polyacetals, polyimides, etc. ;

• soft metals such as lead, tin, silver, indium or their alloys.

The products most frequently used are graphite, molybdenum disulphide and PTFE.

Solid lubricants are used either on their own, as a substitute for greases (dry lubrication), or in combination with conventional lubricants to improve their performance...