Meaning
Composite material combines hard ceramic particles with a metallic binder to achieve high wear resistance. A tungsten carbide cermet is the preferred choice for cutting tools and drill bits due to its extreme hardness and thermal stability. The properties of the final product are tuned by adjusting the ratio between the brittle carbide and the ductile metal.
Cobalt Binder
Metallic phase acts as a glue that holds the hard particles together and provides impact resistance. In a tungsten carbide cermet, cobalt is the most common binder because it wets the carbide surfaces effectively during the manufacturing process. The amount of cobalt determines whether the material is optimized for hardness or for toughness.
Higher binder contents increase the resistance to cracking but lower the cutting speed.
Fracture Toughness
Resistance to crack propagation depends on the mean free path between the carbide grains. A tungsten carbide cermet with a fine grain structure inhibits the growth of cracks through the binder phase. This microstructural design prevents premature failure in heavy duty applications.
Sintering Process
High temperature pressing densifies the powder mixture into a solid component. During the production of a tungsten carbide cermet, the metal binder melts and flows around the solid carbide particles. This liquid phase sintering ensures that all porosity is removed from the bulk material.
