Question

The Titanium Nitride or Titanium Carbonitride coated cutting tools are majorly used to

• A. Make the tool ductile
• B. Reduce friction and wear resistance
• C. Increase tool toughness
• D. Increase thermal conductivity

Hint:

Thin ceramic surface coatings (like TiN, TiC, TiCN) are applied to cutting tools to improve surface-specific properties, such as increasing hardness and reducing friction, rather than modifying bulk properties like toughness or ductility.

Answer 1

The Correct Option is B

TiN and TiCN are hard, thin ceramic layers deposited on a cutting insert by CVD or PVD. Picture the coating as a slippery, low friction skin sitting on top of the tough carbide or HSS body underneath. Because this skin has a low coefficient of friction, the chip slides across the rake face more easily, which cuts down the rubbing and heat generated during cutting, and this in turn also holds back wear at the cutting edge. The tool's own toughness and its thermal conductivity are set by the base material underneath, the thin coating does not change those bulk properties. So the real job of these coatings is to cut down friction and hold back wear at the edge, which is why they are used.