Boron Nitride：Sintered Plate&Crucible
High Temperature Stability
h-BN can withstand temperatures of up to 2000°C in an inert atmosphere and remains stable in an oxidizing environment up to 900°C.
c-BN does not convert to h-BN below 1400°C.
Thermal Property
h-BN has better thermal conductivity than aluminum oxide (parallel to c-axis: 400 W/m·K, perpendicular to c-axis: 30 W/m·K);
It exhibits a low coefficient of thermal expansion (h-BN: parallel to c-axis -2.7×10⁻⁶/°C, perpendicular to c-axis 38×10⁻⁶/°C).
Mechanical Property
h-BN has a low hardness (Mohs hardness ~2) and excellent machinability; c-BN has a hardness second only to diamonds.
h-BN exhibits excellent thermal shock resistance due to its low elastic modulus.
Electrical Property
h-BN is a high-quality insulator (resistivity > 10¹⁴ Ω·cm, dielectric constant ~ 4);
c-BN is a wide-bandgap semiconductor (bandgap width ~ 6.4 eV).
Chemical Inertness
Resistant to corrosion by molten metals (such as aluminum and copper), and does not react with acids/bases (except for concentrated sulfuric acid and molten alkali).
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Electronics and Semiconductor manufacturing
Thermal substrate: h-BN ceramics are used as insulating heat sinks for high power LEDs and RF devices.
Semiconductor devices: PBN crucibles are used for the growth of GaAs and GaN single crystals.
Microwave window materials: h-BN offers excellent transmission properties and is used in radar and plasma equipment.
High temperature metallurgy
Continuous Casting: h-BN serves as a separation ring to prevent steel from sticking together;
Thermocouple Protection Tube: Resistant to molten aluminum and magnesium corrosion.
Mechanical tools
Lubricants: h-BN powder is used for lubricating high-temperature gears and bearings (replacing graphite in oxidative environments);
Ultra-hard tools: c-BN tools process hardened steel and cast iron (with a lifespan ten times that of carbide).
Nuclear energy and Aerospace
Neutron absorption materials: Boron-10 isotope in h-BN is used for nuclear shielding;
Aerospace thermal protection: h-BN composites are resistant to high-temperature oxidation.
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