A LUBRICANT

- (sometimes referred to as "lube") is a substance

(often a liquid) introduced between two moving surfaces

to reduce the friction between them, improving efficiency

and reducing wear.

- have the function of dissolving foreign particles.

Petroleum-based lubricants like Vaseline tend to

dissolve petroleum products such as rubber and plastic;

water-based lubricants will dissolve polar chemicals;

silicone-based lubricants can breakdown silicone toys.

- it protects the internal combustion engines in motor vehicle

and power equipments.

- contain 90% base oil (most often petroleum fractions, called

mineral oils) and less than 10% additives. Vegetable oils or

synthetic liquids such as hydrogenated polyolefins, esters,

silicone, fluorocarbons and many others are sometimes used

as base oils.

- -Lubricants are comprised of a base fluid, usually of

petroleum origin, combined with added chemicals that

enhance performance. Base fluids are collected from two

main sources. Refined crude oil or a mixture of chemical

compounds that perform the same task.

PURPOSE or FUNCTION OF A

LUBRICANT

•Keep moving parts apart

•Reduce friction

•Transfer heat

•Carry away contaminants & debris

•Transmit power

•Protect against wear

•Prevent corrosion

•Seal for gasses

•Stop the risk of smoke and fire of objects

Types of lubricants

- Liquid including emulsions and

suspensions

- Solid lubricants including graphite and

molybdenum disulphide

- Greases (semi-solid)

Solid lubricants

Teflon or PTFE

Teflon or PTFE is typically used as a coating layer on, for

example, cooking utensils to provide a non-stick surface.

Mineral

Graphite, hexagonal Boron nitride. Molybdenum disulfide and

Tungsten disulfide are examples of materials that can be used as

solid lubricants, often to very high temperature. The use of such

materials are still restricted by their poor resistance to oxidation

(e.g., molybdenum disulfide can only be used up to 350C in air,

but 1100C in reducing environments).

Liquid lubricants

- Lanolin (wool grease, natural water repellant)

Water

-Mineral oils

-Vegetable (natural oil)

* Synthetic oils

-Others

-Note: although generally lubricants are based on

one type of base oil or another, it is quite possible

to use mixtures of the base oils to meet

performance requirements.

• They are emulsion of petroleum oils with calcium

soap.

• They are prepared by adding calculated amount of

calcium hydroxide to a hot oil while Under agitation.

The amount of lime can be varied from 10-30% in

calcium-based greases for getting wide range of

consistency from soft paste to hard smooth solid.

• These greases are insoluble in water as a result they

are water resistance. they are Satisfactory use at low

temperature because above 80c,oil and soap begins

to separate Out.

• These greases are suitable for lubricating caterpillar

treads, tractors, water pumps etc.

• They are petroleum oil ,thickened by

mixing soaps.

• They sodium soap content is soluble

in water. Hence they are not water

resistance

and can be used upto 175 c.

• They are suitable for use in ball

bearing which generates frictional

heats.

They are petroleum oil , thickened by mixing

lithium soaps.

These greases are resistance to water and

have good high temperature properties.

• These greases are stable in storage have high

mechanical and oxidation stability.

• They have a melting point about 150 c.

• They are used in aircraft applications at

exchange heights , where temperature as

Low as -55 c may exits.

They are prepared by adding lime to resins and

fatty oils .

The mixture is thoroughly mixed and allowed to

stand when grease floats space

as stiff mass.

They are water resistant and suitable for less

delicate equipment working

under high loads and at low speeds.

Talc, mica or any other suitable filler is also

added to them. They are very cheap

resin grease.