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Lubricants and their functions

Short answer

Lubricating oils are liquid lubricants, mainly mineral oils, that form a film to reduce friction. Their chief functions are reducing friction and wear, cooling, sealing against gas leakage, preventing corrosion, cleaning away debris, and saving energy.

What are lubricating oils? Write the chief functions of lubricants.

A lubricant is a substance introduced between two moving or sliding surfaces to reduce friction and wear between them. Lubricating oils are liquid lubricants, mostly mineral oils from petroleum, which form a thin film between the surfaces and thereby replace solid–solid friction by fluid friction inside the oil.

Chief functions

  1. Reduces friction between moving surfaces by forming a thin film that separates them.
  2. Reduces wear and tear, which increases the life of machine parts.
  3. Acts as a coolant: carries away heat produced by friction.
  4. Acts as a seal: prevents leakage of gases, e.g. between piston rings and cylinder.
  5. Prevents corrosion by coating metal surfaces from air and moisture.
  6. Cleans by washing away dirt, metal particles and carbon deposits.
  7. Saves energy: smoother motion means less power loss and higher efficiency; also reduces noise and vibration.

✓ Answer checked by Claude Opus 5.5 (high effort)

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