Lubricants

Lubricants are substances used to reduce friction and wear between moving surfaces, enabling smoother operation and heat dissipation. They form a protective film that separates contacting surfaces, minimizes metal-to-metal contact, and helps protect against corrosion, contamination, and excessive wear.

They come in liquids and semi-solids. Base oils include mineral oils, synthetic oils such as polyalpha-olefin and esters, and bio-based oils derived from plant sources. Thickened oils, or greases, use soaps or other thickeners to stay in place on components. Gas lubricants are used in specialized high-vacuum or turbine applications.

Additives tailor performance and reliability. Common classes include anti-wear and extreme-pressure agents, anti-oxidants, detergents and dispersants, corrosion inhibitors, pour-point depressants, and viscosity modifiers. Key properties used to select lubricants include viscosity and viscosity index, operating temperature range, pour point, flash point, and shear stability, as well as compatibility with seals, metals, and other materials.

Applications span automotive engines and transmissions, industrial bearings and gears, hydraulic systems, turbines, and machining fluids for cutting and grinding. Different equipment requires specific lubricant types and viscosities, typically specified by manufacturers and industry standards. Proper lubrication also involves maintenance practices to control contamination, monitor condition, and schedule timely changes.

Environmental and safety considerations address biodegradability, toxicity, and spill response. Disposal and recycling follow regulatory requirements, and there is ongoing emphasis on developing low-toxicity and more renewable lubricant formulations to reduce environmental impact. Standards and classification systems help technicians select appropriate products for given operating conditions.