Lubrikation

Lubrikation refers to the process of reducing friction, wear and heat between surfaces in relative motion by introducing a lubricant. The goal is to create a separating film that lowers contact stresses, facilitates heat removal, and protects components from damage.

It can operate in several regimes: hydrodynamic lubrication where a full fluid film supports the load; elastohydrodynamic lubrication in high-load, high-pressure contacts such as gears and rollers; boundary and mixed lubrication where the film is thin and protective adsorption or solid additives reduce wear. The regime depends on speed, load, temperature and lubricant properties.

Lubrikation can involve liquids, gases, or solids. Liquid lubricants include mineral oils and synthetic oils (PAO, esters), often formulated as engine oils, turbine oils, or industrial lubricants. Greases are thickened oils that stay in place. Solid lubricants such as graphite or molybdenum disulfide provide protection in extreme conditions. Essential properties include viscosity and viscosity index, temperature range, pour point, oxidative stability, load-carrying capacity, and compatibility with materials. Additives enhance corrosion resistance, anti-wear performance, detergency and anti-foaming.

Common applications include bearings, gears, piston rings, cams, hydraulic systems, and high-temperature or vacuum environments. Selection depends on load, speed, temperature, contamination, and maintenance constraints. Greases are preferred when a lubricant needs to stay in place; oils offer better heat removal. Food-grade and biodegradable options are used where needed to meet safety or environmental requirements.

Maintenance and monitoring involve lubrication intervals, methods (manual, centralized systems, automatic lubricators), filtration, and oil analysis to detect contamination and degradation. Poor lubrication leads to increased wear, energy loss and potential failure.

See also tribology, lubricants, friction, wear.