Custom Boron Nitride Ceramic Tubes (BN & PBN) for High-Temperature and Insulating Applications

Boron Nitride Tubbing Application

• Vacuum & Heat-Treatment Equipment

  ✅Key Advantages

  1. Dimensional Stability — Low CTE ~1.5–2.0×10⁻⁶/K supports tight coaxial fits in hot zones.
  2. Thermal Path Control — 20–60 W/m·K reduces temperature gradients across sleeves.
  3. Electrical Isolation — ≥10¹² Ω·cm at RT for safe proximity to heating elements.

  ✅ Problem Solved

  A furnace OEM reduced fixture cracking by 35% after replacing alumina sleeves with BN tubes featuring ±0.10 mm ID control. Heat-up time dropped ~8% due to higher conductivity, while coil-to-tube insulation margin exceeded the target dielectric threshold under vacuum bake conditions.

• Semiconductor PVD/CVD/MBE

  ✅Key Advantages

  1. Low Particle Generation — PBN option supports ultra-clean paths for evaporation lines.
  2. Tight Tolerance — End-stepped tubes improve seal integrity at chamber interfaces.
  3. Thermal Compatibility — Low CTE reduces stress at feedthrough junctions.

  ✅ Problem Solved

  A thin-film toolset integrated PBN tubes for source lines; seal leak-rate fell below the internal spec, alignment rework decreased, and campaign length extended one maintenance cycle, lifting line availability without altering power profiles.

• Molten Non-ferrous Metal & Speciality Glass

  ✅Key Advantages

  1. Non-wetting to Many Alloys — Less buildup and easier cleaning in transfer guides.
  2. Erosion Resistance — Stable interfaces reduce contamination pick-up.
  3. Form Factor Flexibility — Thin-wall guides keep flow windows while protecting hardware.

  ✅ Problem Solved

  A casting line switched to BN guide tubes; metal adhesion events declined, changeover time shortened by ~20%, and liner life increased across three production runs, lowering consumable cost per ton.

Boron Nitride (BN) Tube Usage Instructions

• Installation

  1. Verify mating ID/OD, straightness, and concentricity before assembly. Misalignment can cause uneven stress or rotation imbalance in furnace and vacuum systems.
  2. Use compliant graphite or metal gaskets when thermal expansion mismatch exists between BN and metal parts; avoid rigid point loads at clamps.
  3. For sealed or closed-end tubes, ensure a vent or pressure relief path if the system undergoes temperature cycling or gas expansion.
  4. When installing long BN tubes, support both ends to prevent bending and vibration during operation.

• Operation

  1. Use vacuum or inert gas (Ar, N₂) for high-temperature applications above 900 °C; validate maximum air exposure time to prevent oxidation.
  2. Avoid direct flame or plasma impingement on thin-wall sections. Maintain gradual ramp rates (≤10 °C/min for wall <2 mm) to reduce thermal shock.
  3. Keep electrical clearance according to system voltage; BN is an insulator, but may accumulate heat and cause local temperature rise.
  4. Do not expose BN tubes to strong reducing gases (e.g., H₂ at >1000 °C) without protective coating.

• Storage

  1. Store tubes in a dry, dust-free, cushioned environment, ideally in original foam carriers.
  2. Do not stack tubes directly; separate with foam or cardboard layers.
  3. Maintain lot and material identification for traceability and reordering consistency.
  4. Avoid humidity over 60% RH to prevent surface adsorption of moisture.

• Cleaning

  1. Blow surfaces with dry, oil-free compressed air or nitrogen.
  2. If contamination occurs, wipe gently with a lint-free cloth soaked in isopropanol; dry immediately with warm air (<100 °C).
  3. For porous machinable BN, avoid liquid immersion—use low-temperature bake-out (200–300 °C) before reinstallation.
  4. In cleanroom or semiconductor use, apply ultrasonic dry-cleaning or vacuum baking per tool specifications.

• Common Misuse & Fixes

  1. Over-tight Fit Causing Split
  → Increase clearance by 0.05–0.10 mm or add a small chamfer; verify thermal expansion compatibility between BN and mating parts.

  2. Edge Chipping at Clamp
  → Apply edge radius (≥0.5 mm) or use compliant shims such as graphite washers; avoid hard contact with metal fasteners.

  3. Air Over-Temperature Oxidation
  → Operate under inert atmosphere or install a protective sleeve; reduce dwell time at >900 °C in air.

Boron Nitride (BN) Ceramic Tube FAQ

1. Q: What are the main differences between machinable BN tubes and PBN tubes?
   A: Machinable boron nitride tubes (h-BN) are hot-pressed and can be precisely machined into custom geometries with short lead time. Pyrolytic boron nitride (PBN) tubes are CVD-deposited, extremely pure, and designed for ultra-clean semiconductor or evaporation processes where contamination must be minimal.
2. Q: How hot can a boron nitride tube operate?
   A: In vacuum or inert atmospheres, BN tubes can work continuously up to 1800–1900 °C. In air, oxidation starts above 850–900 °C, so the operation should be time-limited or protected by an inert shield.

3. Q: Is a boron nitride tube electrically insulating or conductive?
   A: BN tube is an excellent electrical insulator with resistivity above 10¹² Ω·cm, even at high temperatures. It is commonly used around heaters, electrodes, or thermocouples to prevent arcing or shorting.

4. Q: Can boron nitride tubes replace alumina or quartz tubes?
   A: Yes, in high-vacuum or metal-contact environments where low thermal expansion, non-wetting, and better machinability are required. However, BN is softer than alumina, so it should not be used where mechanical impact is high.

5. Q: What information do I need to request a quotation for a boron nitride tube?
   A: Provide inner/outer diameter, length, tolerance, end configuration (open, closed, stepped), operating temperature, working atmosphere, and quantity. This allows accurate pricing and material-grade selection (h-BN or PBN).
6. Q: How does ADCERAX ensure dimensional accuracy and consistency in BN tube production?
   A: Each tube is CNC-machined, inspected by digital calliper and concentricity gauge, and logged with a QC report showing ID/OD and straightness deviation. Batch traceability and controlled firing parameters guarantee uniform density and tolerance stability across lots.

Boron Nitride Tube Reviews

• ⭐️⭐️⭐️⭐️⭐️
  We replaced alumina sleeves with a machinable boron nitride insulating tube on a 950 °C vacuum line. Dimensional control and non-wetting behavior cut rebuild time and stabilized ramp cycles.
  James R. — Senior Process Engineer, Thermatek Furnaces (USA)
• ⭐️⭐️⭐️⭐️⭐️
  Our team sourced boron nitride tubes directly from the factory. Drawings were matched, IDs were consistent across lots, and packaging protected thin-wall sections during transit.
  Laura M. — Sourcing Manager, ADCERAX customer (Germany)
• ⭐️⭐️⭐️⭐️⭐️
  The PBN tube for our evaporation path lowered the rework on seals. Orientation marks and end steps made integration straightforward.
  Kenji S. — Equipment Engineer, Thin-Film Systems (Japan)
• ⭐️⭐️⭐️⭐️⭐️
  BN ceramic one end closed tube reduced adhesion on aluminum changeovers. We saw faster cleaning and longer intervals between liner swaps.
  Marco V. — Maintenance Lead, Non-Ferrous Casting (Italy)