Silicon Nitride Heater Protection Tubes
Silicon Nitride Ceramic Component
SKU: FWM/SN-HPT-001
- Material
- Silicon Nitride (Si₃N₄) – Gas Pressure Sintered (GPS)
- Size
- Custom sizes available
- MOQ
- 5 pieces per type
- Applications
- Aluminum Casting & Foundry
Silicon Nitride Heater Protection Tubes are high-performance ceramic sleeves designed to protect electric heating elements (resistance wires, SiC rods, MoSi₂ rods, etc.) from high temperature, corrosion, oxidation and mechanical damage in harsh industrial environments.
Send drawing, dimensions, operating temperature, medium and quantity for material grade and dimensional confirmation before quotation.
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Product Description
Review representative product forms and application context below. Final geometry and acceptance criteria are confirmed from the drawing and operating conditions.
Silicon Nitride Heater Protection Tubes are high-performance ceramic sleeves designed to protect electric heating elements (resistance wires, SiC rods, MoSi₂ rods, etc.) from high temperature, corrosion, oxidation and mechanical damage in harsh industrial environments.
Made from Gas Pressure Sintered (GPS) silicon nitride, these tubes offer outstanding high-temperature strength, excellent thermal shock resistance, superior corrosion resistance against molten non-ferrous metals (especially aluminum), and reliable electrical insulation. They enable long-term stable operation of heating systems in melting and holding furnaces, significantly extending service life compared with traditional quartz or metal protection tubes.
A key advantage in aluminum casting is the non-wetting behavior toward molten aluminum — the surface does not adhere to aluminum, reducing buildup and simplifying maintenance.
Manufacturing process (source record): High-purity α-Si₃N₄ powder + sintering aids → dry pressing / CIP → green machining → gas pressure sintering under nitrogen → precision finishing → final inspection.
Quality control (source record): Dimensional inspection, surface quality check, density and porosity verification, and batch traceability.
Data status: the source record is not supplier-verified. Numerical values are typical engineering references, not guaranteed product specifications; final values require grade, drawing and test-basis confirmation.
Product Features
- Long-term operation at 1200–1400 °C with high mechanical strength retention
- Excellent thermal shock resistance (low CTE ≈ 3.1–3.3 × 10⁻⁶/°C)
- Superior corrosion and erosion resistance against molten aluminum, zinc, magnesium and furnace atmospheres
- Good thermal conductivity for efficient and uniform heat transfer
- Reliable high-temperature electrical insulation
- Long service life and low maintenance cost
- High structural reliability and design flexibility
Typical Applications
- Protection of heating elements in aluminum, magnesium and zinc melting & holding furnaces
- Submersible and immersion heaters in non-ferrous metal casting
- Online aluminum melt treatment systems
- Low-pressure and counter-pressure casting equipment
- High-temperature industrial furnaces requiring corrosion and thermal shock resistance
Technical Data
| Property | Unit | Typical Value |
|---|---|---|
| Density | g/cm³ | 3.20 – 3.26 |
| Apparent porosity | % | 0 – 0.2 |
| Elastic modulus | GPa | 300 – 320 |
| Compression strength | MPa | > 1500 |
| Vickers hardness (HV0.5) | GPa | 15 – 16 |
| Fracture toughness | MPa·m¹/² | 7.0 – 9.0 |
| Bending strength | MPa | 700 – 900 |
| Poisson’s ratio | — | 0.25 |
| Linear expansion coefficient | ×10⁻⁶/°C | 3.1 – 3.3 |
| Thermal conductivity | W/(m·K) | 20 – 25 |
| Maximum service temperature | °C | 1200 – 1400 (typical) |
| Volume resistivity | Ω·m | 10¹⁴ |
Typical reference values for material selection only. Final specifications are confirmed against drawing, grade and operating conditions. Values are typical reference data and may vary with grade, geometry and test method. Final specifications confirmed against drawing and operating conditions.
Available Forms
Representative forms are shown for selection. Send drawing, dimensions, operating temperature, medium and quantity for material grade and dimensional confirmation before quotation.
- Straight tubes, flanged tubes, closed-end tubes
- Custom lengths, diameters and wall thicknesses
- Designs compatible with various heating element types
Packaging & Shipping
Packing and shipment arrangements are selected for the confirmed component geometry and order requirements.
| Item | Details |
|---|---|
| Packaging & shipping | Individually protected, cushioned and packed in export cartons or wooden cases according to size, quantity and transport requirements. Payment terms, port of shipment and shipping options confirmed in the quotation. |
About FreeWill Material
FreeWill Material supplies technical ceramic components for demanding industrial applications. Our product range includes silicon carbide, silicon nitride, alumina, zirconia and other engineered ceramic materials.
We work with qualified manufacturing resources in China to support material selection, drawing-based customization, production coordination, inspection documentation and export delivery. Component feasibility, tolerances and material grades are reviewed according to the customer's drawings and operating conditions.
Our focus is to provide international buyers with clear technical communication, practical sourcing support and responsive quotation service for custom ceramic components.
- Drawing-Based Customization
- Material Selection Support
- Inspection Documentation
- Export Coordination
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