Silicon Nitride Thermocouple Protection Tubes
Silicon Nitride Ceramics Family
SKU: FWM/SN-TPT-001
- Material
- Silicon Nitride (Si₃N₄) – Gas Pressure Sintered (GPS) / High-density
- Size
- Custom sizes available (typical OD 16–45 mm, length up to 1200 mm or more)
- MOQ
- 5 pieces per type
- Applications
- Aluminum Casting & Foundry
Silicon Nitride Thermocouple Protection Tubes (also known as Si₃N₄ thermocouple sheaths) are high-performance ceramic tubes designed to protect temperature sensors in molten metal environments, particularly aluminum and other non-ferrous metals.
Send drawing, dimensions, immersion length, operating temperature and quantity for feasibility review and quotation.
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Product Description
Silicon Nitride Thermocouple Protection Tubes (also known as Si₃N₄ thermocouple sheaths) are high-performance ceramic tubes designed to protect temperature sensors in molten metal environments, particularly aluminum and other non-ferrous metals.
Silicon Nitride Thermocouple Protection Tubes (also known as Si₃N₄ thermocouple sheaths) are high-performance ceramic tubes designed to protect temperature sensors in molten metal environments, particularly aluminum and other non-ferrous metals.
Manufactured from Gas Pressure Sintered silicon nitride, these tubes offer outstanding thermal shock resistance, excellent corrosion resistance, non-wetting behavior toward molten aluminum, and high mechanical strength. They enable accurate, continuous temperature monitoring while significantly extending service life compared with cast iron, silicon carbide or alumina tubes, reducing maintenance and improving casting quality.
Product Features
- Non-wetting to molten aluminum — no adhesion, low dross buildup, easy cleaning
- Excellent thermal shock resistance for repeated immersion cycles
- Superior corrosion resistance against molten aluminum, zinc and other non-ferrous metals
- High mechanical strength and long service life
- Good thermal conductivity for fast temperature response
- High-temperature stability and oxidation resistance
Typical Applications
- Temperature measurement in aluminum melting and holding furnaces
- Low-pressure die casting and continuous casting systems
- Non-ferrous metal foundries and smelters
- Launders, pouring troughs and molten metal transfer systems
- Direct and indirect temperature sensing in molten metal
Technical Data
| Property | Unit | Typical Value |
|---|---|---|
| Density | g/cm³ | 3.15 – 3.26 |
| Apparent porosity | % | 0 – 0.2 |
| Young’s Modulus | GPa | 300 – 320 |
| Flexural / Bending Strength | MPa | ≥ 700 – 900 |
| Fracture Toughness | MPa·m¹/² | 6 – 9 |
| Vickers Hardness / HRA | GPa / HRA | 15 – 16 GPa / 92 – 94 |
| Thermal Expansion Coefficient | ×10⁻⁶/°C | 2.95 – 3.3 |
| Thermal Conductivity | W/(m·K) | 20 – 27 |
| Max. Operating Temperature (air) | °C | 1200 – 1400 |
| Dielectric Strength | kV/mm | > 15 |
| Electrical Resistivity | Ω·cm | > 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
Send drawing, dimensions, immersion length, operating temperature and quantity for feasibility review and quotation.
- Straight tubes, flanged tubes, closed-end or open-end designs
- Custom outer/inner diameter, length and wall thickness
- Optional threaded, flanged or grooved joints
Packaging & Shipping
Packing and shipment arrangements are selected for the confirmed tube geometry and order requirements.
| Item | Details |
|---|---|
| Packaging & shipping | Individually protected, cushioned and packed in export cartons or wooden cases according to size and quantity. Terms 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