Tungsten carbide (WC) is an ultra-hard, dense compound of tungsten and carbon with a hexagonal crystal structure. It is most commonly used as a cemented carbide, where WC particles are bonded with a metallic binder—typically cobalt or nickel—to combine extreme hardness with improved toughness.
Composition
Primary Constituent: Tungsten Carbide (WC)
Binders: 5–20 wt% Cobalt (Co) or Nickel (Ni)
Cobalt improves fracture toughness and impact resistance, while nickel enhances corrosion resistance in aggressive environments. Binder content allows tuning between hardness and toughness.
Key Physical Properties
| Property | Typical Value | Notes |
|---|---|---|
| Density | ~15.6 g/cm³ | Nearly twice that of steel |
| Melting Point | ~2780 – 2870 °C | High thermal stability |
| Boiling Point | ~6000 °C | Maintains structure at extreme heat |
| Thermal Conductivity | 80 – 110 W/m·K | Efficient heat dissipation |
| Thermal Expansion | 5.4 – 5.9 µm/m·K | Excellent dimensional stability |
| Electrical Resistivity | ~0.2 µΩ·m | Moderately conductive |
| Hardness (Mohs) | 9 – 9.5 | Near diamond hardness |
Key Mechanical Properties
| Property | Typical Value | Significance |
|---|---|---|
| Compressive Strength | 4780 – 6000 MPa | Exceptional crushing resistance |
| Tensile Strength | ~350 MPa | Limited due to brittleness |
| Flexural Strength | 1800 – 3000 MPa | High bending capability |
| Fracture Toughness | 8 – 15 MPa·m½ | Improved via binders |
| Young’s Modulus | 530 – 700 GPa | Extremely stiff |
| Poisson’s Ratio | ~0.31 | Typical for hard ceramics |
Strengthening & Metallurgical Behavior
Cemented carbides combine hard WC grains with a ductile metal binder that absorbs energy at crack tips. Increasing binder content improves toughness but reduces hardness, while lower binder levels maximize wear resistance.
Finer WC grains increase hardness and abrasion resistance, while coarser grains improve toughness and thermal conductivity.
Microstructure
Hexagonal WC crystals provide inherent rigidity.
Metallic binder phase distributes toughness throughout the structure.
Pure WC without binders is extremely brittle and ceramic-like.
Refining & Processing Properties
Powder preparation via tungsten–carbon reaction
Binder mixing and homogenization
Pressing into near-net shapes
High-temperature sintering in vacuum or controlled atmosphere
Post-sinter grinding, lapping, and surface finishing
Available Forms
Solid carbide rods and rounds
Cutting tool inserts and blanks
Plates and wear components
Mining and drilling parts
Coating and additive manufacturing powders
Custom sintered shapes
Key Characteristics
✔ Extreme hardness and wear resistance
✔ Exceptional compressive strength and stiffness
✔ High thermal stability
✔ Good thermal conductivity
✔ Chemical and corrosion resistance
✔ Tailorable hardness–toughness balance
Applications
Cutting Tools
End mills, inserts, drills, reamers, saw blades
Wear-Resistant Parts
Valve seats, nozzles, bushings, seals, wear plates
Mining & Drilling
Rock cutting tools, drill bits
Precision Engineering
Dies, punches, molds, bearings
Advantages
✔ Superior wear resistance and long service life
✔ Maintains cutting edges under extreme stress
✔ Excellent performance at high temperatures
✔ High stiffness under heavy loads
✔ Cost-effective over lifecycle due to durability
Why Choose Tungsten Carbide?
Tungsten carbide is selected when wear, heat, pressure, and precision dominate design requirements. Its unmatched combination of hardness, thermal stability, and engineered toughness makes it a cornerstone material for tooling, mining, and high-wear industrial applications.