selflubrication

Self-lubrication refers to the ability of a material or component to reduce friction and wear at sliding interfaces without ongoing external lubrication. It typically relies on lubricants that are either built into the material, released during operation, or formed as a protective film at the contact surface.

Mechanisms include solid lubricants dispersed in a matrix that become exposed as wear progresses; diffusion of lubricant species to the interface; transfer films created by contact between mating surfaces; and the formation of boundary or tribolayer films that reduce shear. In polymers, inherent lubricity or additives such as PTFE and graphite contribute to low friction.

Common self-lubricating materials include metal composites (for example, bronze or copper alloys containing graphite), ceramic or ceramic-graphite composites, and polymer-based coatings or composites (polytetrafluoroethylene, PEEK-based materials). Some designs use porous matrices saturated with solid lubricants for gradual release during operation.

Applications include bearings and seals in environments where oil lubrication is undesirable or impractical, such as in vacuum, high temperature, or remote locations; aerospace components, electronics, medical devices, and some MEMS devices. Self-lubricating systems can reduce maintenance requirements and extend service life when conditions are challenging.

Limitations include finite lubricant reserves, sensitivity to temperature and load, potential degradation of the lubricating phase, and higher initial material cost. Performance is highly dependent on operating conditions, surface chemistry, and compatibility of contact partners.