Tungsten carbide with grain size less than 0.2μm is nano tungsten carbide, while superfine crystal tungsten carbide grain size of WC is less than 0.5μm. The two concepts are more overlapping, often treated as the same type of tungsten carbide. 

 

Superfine crystal tungsten carbide can effectively solve the contradiction between hardness and strength of traditional cemented carbide, and achieve three high (high hardness, high strength and high toughness).

 

 

In the production, the compaction performance of the alloy powder deteriorates rapidly as the particle size of WC powder enters the nano scale (<100nm), which shows that the density of the blank is very low. The zonal pressure is much lower than the conventional hard alloy (<90MPa), relative density of preform is generally less than or equal to 33% and uneven density.

 

Especially, in the single heavy pressure forming, the blank will have more surface cracks. As a result, the shrinkage will be too large and uneven in sintering. And the residual porosity is too high, WC grain growth is very uneven, restricting the development and application of superfine crystal tungsten carbide.