Definition:

Lubricants may he defined as any chemical substance introduced between two moving or sliding surfaces with a view to reduce the frictional resistance between them is known as lubricants.

Lubrication may be defined as the “process by which frictional resistance gets reduces; with the use of lubricants is known as lubrication".

Explanation:

• When the moving surfaces are under very high pressure & high load & at high speed, a high temperature is obtained.
• And under these conditions liquid lubricants fails to stick & may decompose & even vaporized.
• To meet these extreme pressure conditions, special additives are added to mineral oils, these are called as extreme pressure additives.
• These extreme pressure additives form more durable film on the metal surfaces, which are capable of withstanding very high load & high temperature.
• Additives are: cl---chlorinated esters

                                p---tricrysyl phosphate .

                                s--- Sulphurised oils.

Function of lubricants: / Ideal lubricant:

1. It reduces the frictional resistance, wear & tear of surfaces.
2. It reduces the wastage of energy, (hereby increases the efficiency of machine
3. It acts as coolant, thereby avoids the loss of energy. & maintains the dimension of the metal parts
4. It acts as sealant there by avoid the escapes of gases from engine.
5. It prevents the attack of the moisture & also acts as cleaner.

• Written by Mansoor Ahmad.
• In category Engineering.
• 13 years ago.

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