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Boron Nitride, BN Ceramic Properties
Boron nitride is a white solid material in the as produced hot
pressed form. It is a low porosity solid. It is easily machined into
complex shapes using standard carbide tooling. The material is
anisotropic in its electrical and mechanical properties due to the
platy hexagonal crystals and their orientation during the hot press
consolidation.
.Key
Boron Nitride Properties |
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High thermal conductivity |
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Low thermal expansion |
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Good thermal shock resistance |
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High electrical resistance |
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Low dielectric constant and loss tangent |
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Microwave transparency |
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Non toxic |
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Easily machined — non abrasive and lubricious |
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Chemically inert |
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Not wet by most molten metals |
Typical Boron Nitride Uses |
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Electronic parts — heat sinks, substrates, coil forms,
prototypes |
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Boron doping wafers in silicon semiconductor processing |
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Vacuum melting crucibles |
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CVD crucibles |
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Microcircuit packaging |
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Sputtering targets |
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High precision sealing, brazing, and metallizing fixtures |
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Microwave tubes |
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Horizontal caster break rings |
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Low friction seals |
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Plasma arc insulators |
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High temperature furnace fixtures and supports |
General Boron Nitride Information
Boron nitride is often referred to as “white graphite” because it is
a lubricious material with the same platy hexagonal structure as
carbon graphite. Unlike graphite, BN is a very good electrical
insulator. It offers very high thermal conductivity and good thermal
shock resistance. BN is stable in inert and reducing atmospheres up
to 2000°C, and in oxidizing atmospheres to 850°C.
Three grades are commonly used, including a boric oxide binder
system, a calcium borate binder system, and a pure diffusion bonded
grade. The boric oxide containing material (Grade BO) absorbs
moisture which causes swelling and property degradation. The calcium
borate containing material (Grade CA) is moisture resistant. The
pure BN material (Grade XP) contains no binders and is used for
extremes of temperature and where purity is important. The boric
oxide material is the most commonly used grade.
Download Boron Nitride grade BO datasheet
Boron Nitride Engineering Properties*
Boron Nitride, Grade BO |
|
Units of Measure |
Orientation to Pressing Direction |
Mechanical |
SI/Metric (Imperial) |
Parallel |
Perpendicular |
Density |
gm/cc (lb/ft3) |
1.9 |
(120) |
1.9 |
(120) |
Porosity |
% (%) |
2.8 |
2.8 |
2.8 |
2.8 |
Color |
— |
white |
white |
white |
white |
Flexural Strength |
MPa (lb/in2x103) |
75.8 |
(11.0) |
113 |
(16.4) |
Elastic Modulus |
GPa (lb/in2x106) |
46.9 |
(6.8) |
73.8 |
(10.7) |
Shear Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Bulk Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Poisson’s Ratio |
— |
— |
— |
— |
— |
Compressive Strength |
MPa (lb/in2x103) |
143 |
(20.8) |
186 |
(27.0) |
Hardness |
Kg/mm2 |
15-24 |
— |
15-24 |
— |
Fracture Toughness KIC |
MPa•m3/2 |
— |
— |
— |
— |
Maximum Use Temperature (inert atm) |
°C (°F) |
1200 |
(2190) |
— |
— |
Thermal |
|
|
|
|
|
Thermal Conductivity |
W/m•°K (BTU•in/ft2•hr•°F) |
30 |
(205) |
33 |
(225) |
Coefficient of
Thermal Expansion |
10–6/°C (10–6/°F) |
11.9 |
(6.6) |
3.1 |
(1.7) |
Specific Heat |
J/Kg•°K (Btu/lb•°F) |
1610 |
(.38) |
— |
— |
Electrical |
|
|
|
|
|
Dielectric Strength |
ac-kv/mm (volts/mil) |
95 |
(2400) |
79 |
(2000) |
Dielectric Constant |
@ 8.8 GHz |
4.6 |
— |
4.2 |
— |
Dissipation Factor |
@ 8.8 GHz |
0.0017 |
— |
0.0005 |
— |
Loss Tangent |
— |
— |
— |
— |
— |
Volume Resistivity |
ohm•cm |
>1014 |
— |
>1015 |
— |
Boron Nitride,
Grade CA |
|
Units of Measure |
Orientation to Pressing Direction |
Mechanical |
SI/Metric (Imperial) |
Parallel |
Perpendicular |
Density |
gm/cc (lb/ft3) |
1.9 |
(120) |
1.9 |
(120) |
Porosity |
% (%) |
15 |
15 |
15 |
15 |
Color |
— |
white |
— |
white |
— |
Flexural Strength |
MPa (lb/in2x103) |
43.4 |
(6.3) |
60 |
(8.7) |
Elastic Modulus |
GPa (lb/in2x106) |
33.8 |
(4.9) |
75 |
(10.9) |
Shear Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Bulk Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Poisson’s Ratio |
— |
— |
— |
— |
— |
Compressive Strength |
MPa (lb/in2x103) |
30 |
(4.4) |
44.5 |
(6.5) |
Hardness |
Kg/mm2 |
14-18 |
— |
14-18 |
— |
Fracture Toughness KIC |
MPa•m1/2 |
— |
— |
— |
— |
Maximum Use Temperature (inert atm) |
°C (°F) |
1150 |
(2100) |
— |
— |
Thermal |
|
|
|
|
|
Thermal Conductivity |
W/m°K (BTU•in/ft2•hr•°F) |
27 |
(187) |
31 |
(215) |
Coefficient of
Thermal Expansion |
10–6/°C (10–6/°F) |
2.95 |
(1.6) |
.87 |
(.5) |
Specific Heat |
J/Kg•°K (Btu/lb•°F) |
1470 |
.35 |
— |
— |
Electrical |
|
|
|
|
|
Dielectric Strength |
ac-kv/mm (volts/mil) |
67 |
(1700) |
— |
— |
Dielectric Constant |
@ 8.8 GHz |
4.3 |
— |
4 |
— |
Dissipation Factor |
@ 8.8 GHz |
0.0014 |
— |
0.0007 |
— |
Loss Tangent |
— |
— |
— |
— |
— |
Volume Resistivity |
ohm•cm |
>1014 |
— |
>1014 |
— |
Boron Nitride, Grade XP |
|
Units of Measure |
Orientation to Pressing Direction |
Mechanical |
SI/Metric (Imperial) |
Parallel |
Perpendicular |
Density |
gm/cc (lb/ft3) |
1.9 |
(120) |
1.9 |
(120) |
Porosity |
% (%) |
14 |
14 |
14 |
14 |
Color |
— |
white |
white |
white |
white |
Flexural Strength |
MPa (lb/in2x103) |
13.8 |
(2) |
21.4 |
(3.1) |
Elastic Modulus |
GPa (lb/in2x106) |
14 |
(2) |
— |
— |
Shear Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Bulk Modulus |
GPa (lb/in2x106) |
— |
— |
— |
— |
Poisson’s Ratio |
— |
— |
— |
— |
— |
Compressive Strength |
MPa (lb/in2x103) |
18 |
(2.6) |
23.4 |
(3.4) |
Hardness |
Kg/mm2 |
3-5 |
— |
3-5 |
— |
Fracture Toughness KIC |
MPa•m1/2 |
— |
— |
— |
— |
Maximum Use Temperature (inert atm) |
°C (°F) |
2000 |
(3630) |
— |
— |
Thermal |
|
|
|
|
|
Thermal Conductivity |
W/m•°K (BTU•in/ft2•hr•°F) |
71 |
(490) |
121 |
(840) |
Coefficient of
Thermal Expansion |
10–6/°C (10–6/°F) |
0.6 |
(.33) |
–.46 |
(–.25) |
Specific Heat |
J/Kg•°K (Btu/lb•°F) |
1470 |
(.36) |
— |
— |
Electrical |
|
|
|
|
|
Dielectric Strength |
ac-kv/mm (volts/mil) |
80 |
(2000) |
80 |
(2000) |
Dielectric Constant |
@ 8.8 GHz |
4 |
— |
4 |
— |
Dissipation Factor |
@ 8.8 GHz |
0.0012 |
— |
0.0003 |
— |
Loss Tangent |
— |
— |
— |
— |
— |
Volume Resistivity |
ohm•cm |
>1014 |
— |
>1014 |
— |
*All properties are room temperature values except as noted.
The data presented is typical of commercially available material and
is offered for comparative purposes only. The information is not to
be interpreted as absolute material properties nor does it
constitute a representation or warranty for which we assume legal
liability. User shall determine suitability of the material for the
intended use and assumes all risk and liability whatsoever in
connection therewith.
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