The drill bits are generally made of cemented carbide. The so-called cemented carbide is based on tungsten carbide powder as a substrate, cobalt powder as binder by pressure, sintering. It usually contains 94% tungsten carbide and cobalt 6%. Because of its high hardness, very wear-resistant, has a certain strength, suitable for high-speed cutting.
However, the toughness is poor, very brittle, in order to improve the performance of cemented carbide, some use on the carbonized substrate chemical vapor deposition of a layer of 5~7 micron of hard titanium carbide (TIC) or titanium nitride (TIN), so that it has a higher hardness. Some use ion implantation technology to inject titanium, nitrogen, and carbon into their matrix at a certain depth, not only to improve the hardness and strength, but also in the drill bit grinding these injection components can be internal migration. Others use physical methods to generate a layer of diamond film on the top of the drill, greatly improving the hardness and wear resistance of the drill bit. The hardness and strength of cemented carbide are related not only to the ratio of tungsten carbide to cobalt, but also to the particles of powders. Ultra-fine cemented carbide bit, the average size of the tungsten carbide phase grain is below 1 microns.This drill bit not only has high hardness but also increases the compressive and flexural strength.