139. Carbide tipped cutting tools are manufactured by powder metallurgy techniques and have a composition of
A. 90% tungsten carbide and 10% cobalt
B. 70% aluminium oxide & 30% silica
C. 30% nickel, 15% chromium & 55% tungsten
D. 65% tungsten & 35% zirconium
✅ The correct answer is option A.