CBN is the second hardest material after synthetic diamond. The process of making CBN abrasive is similar to that of synthetic diamonds: scientists treat hexagonal boron nitride at high temperature and pressure to create cubic boron nitride and treat graphite in the same way to create diamond.

Machinists make CBN grinding wheels by electroplating CBN particles on steel, using electroplated nickel to hold grit in place. A single layer of CBN grit applied to the surface of a metal disc can grind even the hardest surfaces and last for years.

CBN has several attractive characteristics that make it superior to diamond:

A:Withstands heat, especially during high-speed applications.

B:Does not cause grit that can dull bits

C:Stays sharp and cool because it does not react with steel

Diamonds can also react with transition metals, limiting their usefulness for grinding certain materials. Cubic boron nitride is stable and does not tend to react unfavorably with standard transition metals.