Boron nitride (BN) is a crystal composed of nitrogen and boron atoms. It has four different variants: hexagonal boron nitride (h-BN), rhombohedral boron nitride (r-BN), cubic boron nitride (c-BN) and wurtzite boron nitride.

 

This paper mainly describes the knowledge of hexagonal boron nitride and cubic boron nitride in boron nitride variants, and analyzes their differences and differences.

Figure1. Hexagonal boron nitride(left) and cubic boron nitride (right)

1. Hexagonal boron nitride

 

Hexagonal boron nitride (h-BN), also known as "white graphene", is a two-dimensional monoatomic layer material composed of nitrogen and boron atoms alternately. Its layered arrangement is AA'AA' Type. Its structure is similar to that of graphene, so it also has many properties similar to that of graphene.

 

Hexagonal boron nitride (h-BN) is a kind of graphite crystal lattice, which is loose, lubricated, easy to absorb moisture, light, insoluble and high temperature resistant white powder. Hexagonal boron nitride has no obvious melting point, has the property of resistance to chemical erosion, and does not react with general metals, rare earth metals, precious metals, glass, molten salts, etc.

 

Hexagonal boron nitride is an excellent insulator with high thermal conductivity, high oxidation resistance, high chemical and thermal stability and good mechanical properties. It has important applications in composite material modification, sensors, field emission devices, ultraviolet laser devices and oxidation resistant coatings.

2. Cubic boron nitride

 

Cubic boron nitride (c-BN) is a kind of synthetic material. Its hardness is second only to diamond and belongs to super hard material. It is synthesized by hexagonal boron nitride and catalyst under high temperature and high pressure.

 

Cubic boron nitride (CBN) has black, amber and metal plating color. Its particle size is usually less than 1 mm, and it has high thermal stability and chemical inertia. Therefore, CBN is often used as a material for making super hard cutting tools.

 

Therefore, the main difference between hexagonal boron nitride and cubic boron nitride lies in their physical properties

 

Hexagonal boron nitride is white, while cubic boron nitride is mostly black and amber;

 

Hexagonal boron nitride is soft, while cubic boron nitride has high hardness;

 

Hexagonal boron nitride can be used as raw material to synthesize cubic boron nitride;

 

Hexagonal boron nitride is widely used as ceramics, and cubic boron nitride is generally used to make CBN tools.