Cubic boron nitride (CBN), like diamond, has an SP³-bonded tetrahedral cubic crystal structure, characterized by extremely strong atomic bonding. As a result, it exhibits hardness, thermal conductivity, thermal expansion coefficient, and elastic modulus comparable to diamond.

Unlike diamond, however, the surface of cBN is composed of boron and nitrogen atoms with fully saturated covalent bonds, making it highly resistant to chemical reactions. It is less prone to oxidation at high temperatures and does not readily react or diffuse with ferrous metals. Moreover, cBN undergoes a phase transformation only at temperatures above 1500 °C, giving it significantly higher chemical stability and thermal stability than diamond.

These properties make PCBN particularly suitable for machining cast iron, hardened steels, and high-temperature alloys, where diamond tools would otherwise suffer from rapid wear due to chemical reactions.

Due to the fundamental differences between CBN and diamond, PCBN tools should be selected to maximize their strengths, especially for machining hardened steels, cast irons, and other ferrous materials where they offer superior performance.

As an advanced superhard material, PCBN tools provide exceptionally long tool life, high productivity, superior surface finish, and excellent machining accuracy compared with conventional cutting materials, making them the preferred solution for high-hardness and high-precision ferrous metal machining applications.