Characteristics and Properties of c-BN

Cubic boron nitride (c-BN) is a different material altogether from h-BN, with a structure similar to that of diamond, which is characterized by extremely high hardness (second to diamond) and high thermal conductivity.As such, it is a material of great interest and a potential competitor to diamond, particularly for cutting and grinding applications. Its characteristics and properties are shown in Table 10.3 

Summary of Characteristics and Properties of Cubic Boron Nitride 

Hardness 29.89 3.12 GPa (depending on crystal orientation) Compressive Strength 2730 MPa Young s Modulus 650 GPa Fracture Toughness 6.4 MPa m  

Note Test temperature is 20°C unless otherwise stated 

Chemical Resistance. C-BN is essentially inert to all reagents at room temperature. It does not react with carbide formers such as Fe, Co, Ni, Al, Ta, and B at approximately 1000°C (while diamond does) this is a useful characteristic in machining and grinding applications. However, it reacts with aluminum at 1050°C and with Fe and Ni alloys containing Al above 1250°C.P4] 

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