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The hexagonal boron nitride is a white crystal, with a melting point of nearly 3000 ℃, high-temperature resistance, extremely stable chemical performance, strong acid corrosion resistance, and a very high electric insulation performance.
Hexagonal boron nitride (h-BN) is mainly used in refractory materials, semiconductor solid-phase doped sources, structural materials of atomic piles, packaging materials against neutron radiation, rocket engine composition, high-temperature lubricants, and mold agents. Fibers processed with boron nitride can be used as inorganic synthetic engineering materials, widely used in aerospace and defense industries. Cube boron nitride can also be used as a deep well drill bit and high-speed cutting tool.
Physical Properties | HBN | HBR | HBC | HBT |
B+N, % | >95 | >94 | >99 | >99 |
Binder | Boric Oxide | Calcium Borate | None | None |
Binder Melting Point, ℃ | 550 | 1150 | -- | -- |
Maximum Recommended Operating Temperature Oxidizing Atmosphere, ℃ Inert/Vacuum Atmosphere, ℃ |
550-850 550-1600 |
850 1150-1600 |
850 2000-3000 |
850 2000-3000 |
Density, g/cm3 Minimum Typical |
2.00 2.10 |
1.90 2.00 |
1.90 1.95 |
1.70 1.75 |
Porosity, % | 7 | 11 | 13 | 22 |
Hardness, Knoops (KHN, 100g) | 19 | 20 | 16 | 11 |
Specific Heat, J/kg-K (Cal/g℃) @25℃ @700℃ |
808(.193) 1846(.441) |
808(.193) 1846(.441) |
808(.193) 1846(.441) |
808(.193) 1846(.441) |
Pressing Direction | ‖ ⊥ | ‖ ⊥ | ‖ ⊥ | ‖ ⊥ |
Thermal Conductivity, W/m·K @25 ℃ @500 ℃ |
59 33 33 25 |
55 33 33 25 |
28 33 30 24 |
22 19 21 17 |
Coefficient of Thermal Expansion, ppm/℃ 25 ℃ to 1500 ℃ |
4 6 |
3 4 |
0.4 0.8 |
0.1 0.3 |
Flexural Strength, MPa (psi×102) @25 ℃
@1500 ℃
|
89.6 75.8 (13) (11) 26.8 20.6 (3.9) (3) |
51.7 41.3 (7.5) (6) 21.3 18.6 (3.1) (2.7) |
20.6 17.2 (3) (2.5) 48.2 27.5 (7) (4) |
19.3 17.2 (2.8) (2.5) 24.1 18.6 (3.5) (2.7) |
77.9 62.7 (11.3) (9.1) | 62.0 48.2 (9) (7) | 48.2 20.6 (7) (3) | 41.3 20.6 (6) (3) | |
Compressive Strength, MPa (psi×102) | 110.3 124.1 (16) (18) | 68.9 62.0 (10) (9) | 41.3 51.7 (6) (7.5) | 33.1 38.6 (4.8) (5.6) |
Electrical Properties | HBN | HBR | HBC | HBT |
Dielectric Strength, V/mm×102 | 53 | 53 | 54 | 34 |
Dielectric Constant @1GHz @9.3GHz @1MHz |
4.3 4.4 4.2 |
4.2 4.3 4.1 |
4.1 4.3 4.1 |
3.9 3.9 3.8 |
Loss Tangent @1GHz @9.3GHz @1MHz |
.0003 .0002 <.0002 |
.0003 .0002 <.0002 |
.0004 <.0002 <.0002 |
.0003 <.0002 <.0002 |
Volume Resistivity, ohm-cm @25 ℃ @700 ℃ |
>1015 108 |
>1015 108 |
>1015 1010 |
>1015 1010 |