| | Boron Nitride, BN 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 Properties |
 | High thermal conductivity | |
| Low thermal expansion | |
| Good thermal shock resistance | |
| High electrical resistance | |
| Low dielectric constant and loss tangent | |
| Microwave transparency | |
| Non toxic | |
| Easily machined — non abrasive and lubricious | |
| Chemically inert | |
| Not wet by most molten metals | .
Typical Uses | |
| Electronic parts — heat sinks, substrates, coil forms, prototypes | |
| Boron doping wafers in silicon semiconductor processing | |
| Vacuum melting crucibles | |
| CVD crucibles | |
| Microcircuit packaging | |
| Sputtering targets | |
| High precision sealing, brazing, and metallizing fixtures | |
| Microwave tubes | |
| Horizontal caster break rings | |
| Low friction seals | |
| Plasma arc insulators | |
| High temperature furnace fixtures and supports | General 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 2800°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. Back to top 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) | 1800 | (3250) | — | — | | 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) | 1800 | (3200) | — | — | | 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) | 3000 | (5400) | — | — | | 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. Back to top Standard Products | Custom Products and Services | Case Studies | Materials
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