Boron Nitride Ceramics
Hot-Pressed Boron Nitride Ceramic Tube
Custom hot-pressed boron nitride ceramic tubes providing high-temperature electrical insulation, thermal-shock resistance, and excellent machinability for vacuum, electronic, and molten-metal applications.
Detailed Product Information
Typical Technical Properties
|
Parameter |
Typical Value |
|
Material |
Hot-pressed hexagonal boron nitride |
|
Abbreviation |
HPBN / hBN |
|
Color |
White or ivory |
|
Density |
1.9–2.2 g/cm³ |
|
Thermal conductivity |
Approximately 40–50 W/(m·K) |
|
Coefficient of thermal expansion |
Approximately 6.5–7.5 × 10⁻⁶/K |
|
Volume resistivity |
>10¹² Ω·m |
|
Dielectric constant |
Approximately 3.8–4.3 |
|
Dielectric strength |
Grade and test-method dependent |
|
Flexural strength |
>35 MPa |
|
Compressive strength |
>200 MPa |
|
Recommended temperature in oxidizing atmosphere |
Up to approximately 850°C |
|
Maximum temperature in vacuum or inert atmosphere |
Up to approximately 2,000°C, depending on grade and conditions |
HPBN is an anisotropic material. Thermal conductivity, thermal expansion, and mechanical properties may vary according to grade and material orientation.
Hot-Pressed Boron Nitride Ceramic Tube
Hot-pressed boron nitride (HPBN) ceramic tubes combine high-temperature electrical insulation, thermal-shock resistance, chemical stability, and excellent machinability. They are manufactured from hexagonal boron nitride powder consolidated under high temperature and pressure to form a smooth, dense white ceramic.
TecCera supplies custom HPBN tubes, sleeves, insulating conduits, and hollow components for vacuum equipment, molten-metal handling, electronic systems, and high-temperature processing applications.
Key Features
- Excellent electrical insulation at elevated temperatures
- High volume resistivity and low dielectric constant
- Good thermal conductivity
- Low thermal expansion
- Excellent thermal-shock resistance
- High-temperature stability in vacuum and inert atmospheres
- Good chemical inertness
- Low coefficient of friction
- Non-wetting by many molten metals and glasses
- Easily machined into complex and precision components
Typical Applications
- High-temperature electrical insulating tubes
- Vacuum-furnace insulating sleeves
- Molten-metal transfer tubes and nozzles
- Thermocouple and sensor protection components
- Plasma-processing insulators
- CVD and PVD equipment components
- Microwave and vacuum-tube components
- Coil forms and high-frequency electrical components
- Brazing and metallizing fixtures
- High-temperature furnace supports
- Custom laboratory and research components
Customization Options
- Custom outside and inside diameters
- Straight, stepped, tapered, or flanged structures
- Blind or through holes
- Threads, grooves, slots, and shoulders
- Custom lengths and wall thicknesses
- Precision turning, milling, and drilling
- Prototype and small-batch production
Frequently Asked Questions
Q1: What are the advantages of HPBN tubes compared with alumina tubes?
HPBN tubes provide better machinability, thermal-shock resistance, non-wetting performance, and high-temperature stability in vacuum or inert atmospheres. However, HPBN has lower mechanical strength, hardness, and wear resistance than alumina and is not suitable for every load-bearing application.
Q2: Can HPBN tubes be machined using conventional tools?
Yes. HPBN can generally be machined using conventional lathes, milling equipment, and carbide tools. Achievable tolerances depend on tube diameter, wall thickness, length, geometry, and material grade.
Q3: What is the maximum operating temperature?
In oxidizing atmospheres, the recommended operating temperature is generally limited to approximately 850°C. In vacuum or inert atmospheres, selected high-purity grades may operate at temperatures approaching 2,000°C. The actual limit depends on the grade, atmosphere, load, and exposure time.
Q4: Can you manufacture thin-wall or precision HPBN tubes?
Yes, subject to dimensional and structural evaluation. Please provide the outside diameter, inside diameter, length, tolerance, operating atmosphere, and service temperature for technical review.
Q5: Is HPBN suitable for all vacuum applications?
Not necessarily. Different HPBN grades may contain different binders or additives that affect purity, moisture resistance, outgassing, and maximum operating temperature. The appropriate grade should be selected according to the required vacuum level and process environment.
The properties above are typical reference values and may vary according to material grade, orientation, component geometry, and test method. Contact TecCera for grade-specific data and custom manufacturing evaluation.