lubricates

Lubricants are substances applied to reduce friction between moving surfaces. They form a film that separates components, enabling smoother motion, reducing wear, and helping to manage heat. In addition to lubricating, many lubricants provide protection against corrosion and can carry away contaminants.

Common lubricant types include liquid oils (mineral and synthetic oils), greases (thickened oils), and solid lubricants such as graphite or molybdenum disulfide. Other classes include hydraulic fluids, engine and gear oils, and cutting or metalworking fluids. Bio-based and biodegradable lubricants are also used in environmentally sensitive applications.

Key properties include viscosity (resistance to flow), often specified by viscosity grades, and viscosity index (temperature dependence). Other important characteristics are pour point, flash point, lubricity, film strength, and resistance to oxidation. Additives provide anti-wear, detergency, rust inhibition, anti-foam, and corrosion protection.

Lubrication operates in regimes such as hydrodynamic, elastohydrodynamic, and boundary lubrication, depending on speed, load, and surface roughness. Selection considers base oil, viscosity, operating temperature, load, environment, and compatibility with materials and seals.

Lubricants find use in automotive engines and transmissions, industrial bearings, turbines, gearboxes, and machinery, as well as metalworking and other manufacturing processes.

Maintenance includes correct specification, regular change intervals, contamination control, and storage in proper conditions. Environmental considerations emphasize biodegradability and responsible disposal, while safety data sheets provide handling guidance.