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Boron Nitride ( BN )

Material Information

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We stock and supply the following standard forms:
Rod Sheet Sputtering Target Tube
Rod Sheet Sputtering Target Tube

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General Description:  

Boron Nitride exhibits a hexagonal structure and is sometimes known as white graphite, due to its lubricity, anisotropic properties, heat resistance, and high thermal conductivity. This latter property, combined with a low thermal expansion, leads to excellent resistance to thermal shock. All three forms, Hot Pressed, Pyrolytic and Hot Isostatic Pressed, can be used at very high temperatures. However, in an oxidising atmosphere the maximum use temperature is 850-900C. Hot Pressed and Hot Isostatic Pressed Boron Nitride are produced by densification of powder, whereas Pyrolitic Boron Nitride is produced by Chemical Vapour Deposition (CVD), depositing onto graphite at temperatures in excess of 1800C.

Boron Nitride differs from graphite in having a high dielectric strength and low dielectric constant and is often used as an electrical insulator at very high temperatures. Chemically inert, Boron Nitride is used as crucibles for molten metals. Boron Nitride is non-toxic and transparent to microwaves. It may be machined to close tolerances.

   

Chemical Resistance

Acids - concentrated Fair
Acids - dilute Fair
Alkalis Fair
Halogens Poor
Metals Good

Electrical Properties

Dielectric constant 4.3
Dielectric strength ( kV mm-1 ) 40-200
Volume resistivity @25C ( Ohmcm ) 1011-1014

Mechanical Properties

Compressive strength ( MPa ) 30-120
Shear strength ( MPa ) 12-25
Tensile modulus ( GPa ) 20-35

Physical Properties

Apparent porosity ( % ) 2-15
Density ( g cm-3 ) 1.9-2.2

Thermal Properties

Coefficient of thermal expansion @20-1000C ( x10-6 K-1 ) 1.0-36
Specific heat @25C ( J K-1 kg-1 ) 800-2000
Sublimation point ( C ) 2600-2800
Thermal conductivity @20C ( W m-1 K-1 ) 15-50
Upper continuous use temperature ( C ) 950-2500

Buy Boron Nitride on-line

We stock and supply the following standard forms:
Rod Sheet Sputtering Target Tube
Rod Sheet Sputtering Target Tube

Choose a form to search our on-line catalogue  

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