Characteristics and Properties of h-BN

Boron nitride has two crystalline forms, hexagonal (h-BN) and cubic (c-BN), with much different properties. Hexagonal BN is the more important and has many industrial applications. Its structure is similar to that of graphite which it resembles in many ways. It has a very large anisotropy in the crystal with resulting anisotropic properties. 

H-BN is produced by hot-pressing the powder or by CVD. The processes impart different properties. The hot-pressed material shows less anisotropy than the CVD BN, since the powder grains are randomly oriented. CVD BN is usually a turbostratic boron nitride with warped basal planes and lattice defects. It is also known as pyrolytic boron nitride or PBN.1 11 ] 

Summary of Characteristics and Properties of CVD Hexagonal Boron Nitride 

Composition BN Molecular Weight 24.816 g/mol Color white to transparent Density 2.1 g/cm  

Porosity (helium admittance) 2 x 10 cm.sec Space Group F43m 

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