High Purity and Density: Purity up to 99.999%, with a dense, pore-free surface structure, excellent gas tightness, and low helium permeability.
High-Temperature and Thermal Properties: Excellent high-temperature resistance, with strength increasing as temperature rises. It also offers outstanding thermal shock resistance and anisotropic thermal conductivity.
Chemical Inertness: Resistant to corrosion from acids, alkalis, salts, and organic reagents. It is non-wetting and non-reactive with most molten metals and semiconductor materials.
Electrical and Special Properties: High electrical resistivity and dielectric strength, low dielectric constant and low dielectric loss tangent, as well as good microwave and infrared transparency.
Anisotropic Mechanical Performance: Exhibits significant anisotropy in mechanical, thermal, and electrical properties.
| Property | Unit | Value |
|---|---|---|
| Density | g/cm³ | 1.95–2.20 |
| Tensile Strength | N/mm² | 102 |
| Flexural Strength | N/mm² | 243 |
| Compressive Strength | N/mm² | 244 |
| Thermal Conductivity (200°C) | W/(m·K) | 60 (a) / 2.60 (c) |
| Thermal Expansion Coefficient (200°C) | K⁻¹ | 2.0 × 10⁻⁶ (a) |
| Dielectric Constant (Room Temperature) | — | 5.81 |
| Electrical Resistivity | Ω·cm | 2.4 × 10¹⁵ |
Semiconductor Crystal Growth: Used as crucibles for LEC, VGF, VB, and MBE methods in the growth of III–V compound semiconductor single crystals such as GaAs, InP, and GaP. Its high purity and chemical inertness effectively prevent melt contamination.
OLED Evaporation Sources: Applied in evaporation crucibles and support structures for OLED manufacturing, providing high electrical insulation, excellent thermal stability, and minimal gas release.
High-Temperature Protective Coatings: Used as PBN coatings for graphite heaters and graphite crucibles, preventing high-temperature volatilization and contamination.
Special Metallurgy and Melting: Serves as crucibles for high-purity metal evaporation, deposition, and melting processes, capable of withstanding various molten metals without reaction.
Electronic Devices and Windows: Used in traveling-wave tube (TWT) support rods, MOCVD insulating plates, and infrared/microwave transmission windows, leveraging its electrical insulation, wave transparency, and high-temperature stability.
Aerospace and Vacuum Equipment: Applied in high-temperature vacuum furnace insulation components and high-temperature insulating fluid nozzles, meeting the requirements for thermal insulation, electrical insulation, and structural stability in extreme environments.
