lubricant

lu·bri·cant

L0277900 (lo͞o′brĭ-kənt)n.1. A substance, such as grease or oil, that reduces friction when applied as a surface coating to moving parts.2. A slippery liquid, gel, or oil that is used to reduce friction on or soreness of body tissue.3. One that facilitates conversation or cooperation: saw coffee as a social lubricant.

lu′bri·cant adj.

lubricant

(ˈluːbrɪkənt) na lubricating substance, such as oiladjserving to lubricate[C19: from Latin lūbricāns, present participle of lūbricāre. See lubricate]

lu•bri•cant

(ˈlu brɪ kənt)

n. 1. a substance, as oil or grease, for lessening friction, esp. in a mechanism. 2. something that increases ease of functioning. adj. 3. capable of or used in lubricating.

Thesaurus

Noun

lubricant - a substance capable of reducing friction by making surfaces smooth or slipperylube, lubricating substance, lubricatorsubstance - a particular kind or species of matter with uniform properties; "shigella is one of the most toxic substances known to man"drilling fluid, drilling mud - a mixture of clays and chemicals and water; pumped down the drill pipe to lubricate and cool the drilling bit and to flush out the cuttings and to strengthen the sides of the holemotor oil - oil used to lubricate the moving parts of a motor

lubricant

noun lubricator, oil, grease industrial lubricants

Translations

润滑剂

lubricate

(ˈluːbrikeit) verb to oil (a machine etc) to make it move more easily and smoothly. 使润滑，加润滑油 ˌlubriˈcation noun润滑ˈlubricant noun something (oil etc) which lubricates. 润滑剂

Lubricant

lubricant

[′lü·brə·kənt] (materials) A substance used to reduce friction between parts or objects in relative motion.

Lubricant

any of the substances that exhibit a lubricating action. These substances are used in the lubrication of machine parts in relative motion and in the pressure shaping of metals. Substances used as lubricants include oils derived for the most part from petroleum and synthetic oils, greases, solids (graphite, molybdenum disulfide, polymers with fillers), gases (air, vapors of hydrocarbons, halogen derivatives of methane), and surfactants (soaps, glycerol). Lubricants are placed in groups and grades depending on their state of aggegation, properties, and purpose.

REFERENCES

Rozenberg, Iu. A. Vliianie smazochnykh masel na dolgovechnost’ i nadezhnost’ detalei mashin. Moscow, 1970.
Tovarnye nefteprodukty, ikh svoistva i primenenie: Spravochnik. Edited by N. G. Puchkov. Moscow, 1971.
Maiorova, L. A. Tverdye neorganicheskie veshchestva v kachestve vysokotemperaturnykh smazok. Moscow, 1971.

Lubricant

A gas, liquid, or solid used to prevent contact of parts in relative motion, and thereby reduce friction and wear. In many machines, cooling by the lubricant is equally important. The lubricant may also be called upon to prevent rusting and the deposition of solids on close-fitting parts.

Crude petroleum is an excellent source of lubricants because a very wide range of suitable liquids, varying in molecular weight from 150 to over 1000 and in viscosity from light machine oils to heavy gear oils, can be produced by various refining processes (see table). In order to standardize on nomenclature for oils of differing viscosity, the Society of Automotive Engineers (SAE) has established viscosity ranges for the various SAE designations (see table).

It is often desirable to add various chemicals to lubricating oils to improve their physical properties or to obtain some needed improvement in performance. These include viscosity-index improvers, pour-point depressants, antioxidants, anti-wear and friction-reducing additives, and dispersants.

Synthetic lubricants may be superior to mineral lubricants in some applications. The main advantage of synthetics is that they have a greater operating range than a mineral oil. Included in this class are esters, containing oxidation inhibitors and sometimes mild extreme pressure additives, silicones, and the polyglycols, such as polypropylene and ethylene oxides.

Viscosity of oils for various applications
	Viscosity in centistokes
Application	at 25°C (77°F)	Primary function
Engine oils
SAE 10W	60–90	Lubricate piston rings,
SAE 20	90–180	cylinders, valve gear,
SAE 30	180–280	bearings; cool piston;
SAE 40	280–450	prevent deposition on
SAE 50	450–800	metal surfaces

Gear oils		Prevent metal contact
SAE 80	100–400	and wear of spur
SAE 90	400–1000	gears, hypoid gears,
SAE 140	1000–2200	worm gears; cool
		gear cases

Aviation engine oils	220–700	Same as engine oils

Torque converter fluid	80–140	Lubricate, transmit
		power

Hydraulic brake fluid	35	Transmit power

Refrigerator oils	30–260	Lubricate compressor
		pump

Steam-turbine oil	55–300	Lubricate reduction
		gearing, cool

Steam cylinder oil	1500–3300	Lubricate in presence of
		steam at high temperatures

The most useful solid lubricants are those with a layer structure in which the molecular platelets will readily slide over each other. Graphite, molybdenum disulfide, talc, and boron nitride possess this property. A unique type of solid lubricant is provided by the plastic polytetrafluoroethylene (PTFE). The principal difficulty encountered with the use of solid lubricants is that of maintaining an adequate lubricant layer between the sliding metal surfaces.

A lubricating grease is a solid or semifluid lubricant comprising a thickening (or gelling) agent in a liquid lubricant. Other ingredients imparting special properties may be included. An important property of a grease is its solid nature; it has a yield value. This enables grease to retain itself in a bearing assembly without the aid of expensive seals, to provide its own seal against the ingress of moisture and dirt, and to remain on vertical surfaces and protect against moisture corrosion, especially during shut-down periods.

lubricant

lu·bri·cant

lubricant

lu•bri•cant

lubricant

lubricate

Lubricant

lubricant

Lubricant

REFERENCES

Lubricant

lubricant

lubricant

lubricant

lubricant

Synonyms for lubricant

noun lubricator

Synonyms

Synonyms for lubricant

noun a substance capable of reducing friction by making surfaces smooth or slippery

Synonyms

Related Words