A Lubricant is a Substance Introduced to Reduce Friction Between Moving Surfaces

8/2/2019 A Lubricant is a Substance Introduced to Reduce Friction Between Moving Surfaces

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artificial joints), ultrasound examination, internal examinations for males andfemales, and the use ofpersonal lubricant for sexual purposes.

Purpose

Lubricants perform the following key functions.

Keep moving parts apart Reduce friction Transfer heat Carry away contaminants & debris Transmit power Protect against wear Prevent corrosion Seal for gases Stop the risk of smoke and fire of objects

Types of lubricants

In 1999, an estimated 37,300,000 tons of lubricants were consumed worldwide. [1]

Automotive applications dominate, but other industrial, marine, and metalworking applications are also big consumers of lubricants. Although air and othergas-based lubricants are known, e.g., in fluid bearings), liquid and solid lubricantsdominate the market, especially the former.

Lubricants are generally composed of a majority of base oil plus a variety ofadditives to impart desirable characteristics. Although generally lubricants are

based on one type of base oil, mixtures of the base oils also are used to meetperformance requirements.

Base oil groups

Mineral oil term is used to encompass lubricating base oil derived from crude oil.TheAmerican Petroleum Institute (API) designates several types of lubricantbase oil.

Group I Saturates 0.03%, and Society ofAutomotive Engineers (SAE) viscosity index (VI) of 80 to 120

Manufactured by solvent extraction, solvent or catalytic dewaxing, andhydro-finishing processes. Common Group I base oil are 150SN (solventneutral), 500SN, and 150BS (brightstock)

Group II Saturates over 90% and sulfur under 0.03%, and SAEviscosity index of 80 to 120
http://en.wikipedia.org/wiki/Replacement_jointhttp://en.wikipedia.org/wiki/Personal_lubricanthttp://en.wikipedia.org/wiki/Lubricant#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Fluid_bearinghttp://en.wikipedia.org/wiki/Oilhttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/American_Petroleum_Institutehttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Viscosity_indexhttp://en.wikipedia.org/wiki/Replacement_jointhttp://en.wikipedia.org/wiki/Personal_lubricanthttp://en.wikipedia.org/wiki/Lubricant#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Fluid_bearinghttp://en.wikipedia.org/wiki/Oilhttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/American_Petroleum_Institutehttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Viscosity_index


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Manufactured by hydrocracking and solvent or catalytic dewaxingprocesses. Group II base oil has superior anti-oxidation properties sincevirtually all hydrocarbon molecules are saturated. It has water-white color.

Group III Saturates > 90%, sulfur


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materials are preferred. Common ones include high oleiccanola oil, castor oil, palm oil, sunflower seed oil and rapeseedoil from vegetable, and Tall oil from tree sources. Manyvegetable oils are often hydrolyzed to yield the acids which aresubsequently combined selectively to form specialist synthetic

esters. Other naturally derived lubricants include lanolin (woolgrease, a natural water repellent).

Whale oil was a historically important lubricant, with some usesup to the latter part of the 20th century as a friction modifieradditive forautomatic transmission fluid.

In 2008, the biolubricant market was around 1% of UKlubricant sales in a total lubricant market of 840,000tonnes/year.

Lanolin is a natural water repellent, derived from sheep woolgrease, and is an alternative to the more common petro-chemical based lubricants. This lubricant is also a corrosioninhibitor, protecting against rust, salts, and acids.

Watercan also be used on its own, or as a major component incombination with one of the other base oils. Commonly used inengineering processes, such as milling and lathe turning.

Synthetic oils

Polyalpha-olefin (PAO) Synthetic esters Polyalkylene glycols (PAG) Phosphate esters Alkylated naphthalenes (AN) Silicate esters Ionic fluids

Solid lubricants

Main article: Dry lubricant

PTFE:polytetrafluoroethylene (PTFE) is typically used as acoating layer on, for example, cooking utensils to provide anon-stick surface. Its usable temperature range up to 350 Cand chemical inertness make it a useful additive in specialgreases. Under extreme pressures, PTFE powder or solids isof little value as it is soft and flows away from the area ofcontact. Ceramic or metal or alloy lubricants must be usedthen. "Teflon" is a brand of PTFE owned by DuPont Co.
http://en.wikipedia.org/wiki/Canola_oilhttp://en.wikipedia.org/wiki/Castor_oilhttp://en.wikipedia.org/wiki/Palm_oilhttp://en.wikipedia.org/wiki/Sunflower_seed_oilhttp://en.wikipedia.org/wiki/Rapeseed_oilhttp://en.wikipedia.org/wiki/Rapeseed_oilhttp://en.wikipedia.org/wiki/Tall_oilhttp://en.wikipedia.org/wiki/Lanolinhttp://en.wikipedia.org/wiki/Whale_oilhttp://en.wikipedia.org/wiki/Oil_additivehttp://en.wikipedia.org/wiki/Automatic_transmission_fluidhttp://en.wikipedia.org/wiki/Lanolinhttp://en.wikipedia.org/wiki/Sheephttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Polyalpha-olefinhttp://en.wikipedia.org/wiki/Estershttp://en.wikipedia.org/w/index.php?title=Polyalkylene&action=edit&redlink=1http://en.wikipedia.org/wiki/Glycolshttp://en.wikipedia.org/wiki/Phosphate_esterhttp://en.wikipedia.org/w/index.php?title=Alkylated_naphthalenes&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Silicate_esters&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Ionic_fluids&action=edit&redlink=1http://en.wikipedia.org/wiki/Dry_lubricanthttp://en.wikipedia.org/wiki/Polytetrafluoroethylenehttp://en.wikipedia.org/wiki/Canola_oilhttp://en.wikipedia.org/wiki/Castor_oilhttp://en.wikipedia.org/wiki/Palm_oilhttp://en.wikipedia.org/wiki/Sunflower_seed_oilhttp://en.wikipedia.org/wiki/Rapeseed_oilhttp://en.wikipedia.org/wiki/Rapeseed_oilhttp://en.wikipedia.org/wiki/Tall_oilhttp://en.wikipedia.org/wiki/Lanolinhttp://en.wikipedia.org/wiki/Whale_oilhttp://en.wikipedia.org/wiki/Oil_additivehttp://en.wikipedia.org/wiki/Automatic_transmission_fluidhttp://en.wikipedia.org/wiki/Lanolinhttp://en.wikipedia.org/wiki/Sheephttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Polyalpha-olefinhttp://en.wikipedia.org/wiki/Estershttp://en.wikipedia.org/w/index.php?title=Polyalkylene&action=edit&redlink=1http://en.wikipedia.org/wiki/Glycolshttp://en.wikipedia.org/wiki/Phosphate_esterhttp://en.wikipedia.org/w/index.php?title=Alkylated_naphthalenes&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Silicate_esters&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Ionic_fluids&action=edit&redlink=1http://en.wikipedia.org/wiki/Dry_lubricanthttp://en.wikipedia.org/wiki/Polytetrafluoroethylene


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Inorganic solids:Graphite, hexagonal boron nitride,molybdenum disulfide and tungsten disulfide are examples ofmaterials that can be used as solid lubricants, often to veryhigh temperature. The use of some such materials issometimes restricted by their poor resistance to oxidation (e.g.,

molybdenum disulfide can only be used up to 350C in air, but1100C in reducing environments).

Metal/alloy: Metal alloys, composites and pure metals can beused as grease additives or the sole constituents of slidingsurfaces and bearings. Cadmium and Gold are used for platingsurfaces which gives them good corrosion resistance andsliding properties, Lead, Tin, Zinc alloys and various Bronzealloys are used as sliding bearings, or their powder can beused to lubricate sliding surfaces alone, or as additives togreases.

[edit] Aqueous lubrication

Aqueous lubrication is of interest in a number of technologicalapplications. Strongly hydrated brush polymers such as PEGcan act as lubricants at liquid solid interfaces. By continuousrapid exchange of bound water with other free watermolecules, these polymer films keep the surfaces separatedwhile maintaining a high fluidity at the brushbrush interface athigh compressions, thus leading to a very low coefficient offriction.
http://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Boron_nitridehttp://en.wikipedia.org/wiki/Molybdenum_disulfidehttp://en.wikipedia.org/wiki/Tungsten_disulfidehttp://en.wikipedia.org/wiki/Solid_lubricanthttp://en.wikipedia.org/wiki/Cadmiumhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Tinhttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Bronzehttp://en.wikipedia.org/w/index.php?title=Lubricant&action=edit&section=15http://en.wikipedia.org/wiki/Polymer_brushhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Boron_nitridehttp://en.wikipedia.org/wiki/Molybdenum_disulfidehttp://en.wikipedia.org/wiki/Tungsten_disulfidehttp://en.wikipedia.org/wiki/Solid_lubricanthttp://en.wikipedia.org/wiki/Cadmiumhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Tinhttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Bronzehttp://en.wikipedia.org/w/index.php?title=Lubricant&action=edit&section=15http://en.wikipedia.org/wiki/Polymer_brush

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A Lubricant is a Substance Introduced to Reduce Friction Between Moving Surfaces