Silicon Nitride Thermocouple Protection Tubes

• High-performance Silicon Nitride (Si₃N₄) Thermocouple Protection Tubes
• Excellent high-temperature strength
• Exceptional thermal shock resistance
• Low coefficient of thermal expansion
• Excellent oxidation resistance
• Excellent corrosion resistance
• Excellent resistance to molten aluminum and non-ferrous metals
• High hardness and wear resistance
• Good thermal conductivity
• Excellent dimensional stability
• Long service life
• Fast thermal response compared with many conventional ceramics
• Protects thermocouples from mechanical and chemical damage
• Suitable for continuous temperature measurement
• Available in straight and closed-end configurations
• Precision-machined dimensions available
• Custom lengths and diameters available
• COA available

Property	Specification
Product Name	Silicon Nitride Thermocouple Protection Tube
Material	Silicon Nitride (Si₃N₄)
Chemical Formula	Si₃N₄
CAS Number	12033-89-5
Material Type	Technical Ceramic
Appearance	Gray / Dark Gray
Purity	Grade Dependent
Density	~3.1–3.3 g/cm³
Hardness	High
Thermal Conductivity	~20–80 W/m·K, Grade Dependent
Coefficient of Thermal Expansion	Low
Thermal Shock Resistance	Excellent
Maximum Operating Temperature	Typically ~1,000–1,400°C, Grade Dependent
Outer Diameter	Custom
Inner Diameter	Custom
Wall Thickness	Custom
Length	Custom
Tube Configuration	Open-End / Closed-End / Custom
Surface Finish	As-Fired / Ground / Polished
Manufacturing	Reaction-Bonded / Sintered / Hot-Pressed
Packaging	Protective / Custom

• Sintered Silicon Nitride Thermocouple Tubes
• Reaction-Bonded Silicon Nitride Protection Tubes
• Hot-Pressed Silicon Nitride Tubes
• High-Purity Silicon Nitride Protection Tubes
• High-Density Si₃N₄ Thermocouple Tubes
• High-Temperature Silicon Nitride Tubes
• Thermal-Shock-Resistant Si₃N₄ Tubes
• Molten Aluminum-Resistant Silicon Nitride Tubes
• Foundry-Grade Silicon Nitride Protection Tubes
• Furnace-Grade Silicon Nitride Tubes
• Industrial-Grade Si₃N₄ Tubes
• Custom Silicon Nitride Thermocouple Protection Tubes

1. What are Silicon Nitride Thermocouple Protection Tubes?

Silicon Nitride Thermocouple Protection Tubes are ceramic tubes used to protect thermocouple sensors from high temperatures, molten metals, corrosive environments, oxidation, and mechanical damage.

2. Why is silicon nitride used for thermocouple protection?

Silicon nitride ceramic provides excellent thermal shock resistance, high-temperature strength, low thermal expansion, corrosion resistance, and resistance to molten non-ferrous metals, making it well suited for demanding temperature measurement.

3. What are Silicon Nitride Thermocouple Tubes used for?

Applications include molten aluminum temperature measurement, foundries, non-ferrous metal processing, industrial furnaces, heat-treatment equipment, kilns, semiconductor processing, and high-temperature process control.

4. Can Silicon Nitride Protection Tubes be used in molten aluminum?

Yes. Specialized molten aluminum-resistant silicon nitride thermocouple protection tubes are widely used for temperature measurement in aluminum processing applications. The appropriate grade should be selected based on alloy, temperature, immersion time, and operating conditions.

5. What temperature can Silicon Nitride Thermocouple Tubes withstand?

The operating temperature depends on the specific Si₃N₄ grade and environment. Many grades are suitable for temperatures around 1,000–1,400°C, while the exact continuous-use limit should be confirmed from the manufacturer's specification.

6. Are closed-end thermocouple protection tubes available?

Yes. REG Metals can source closed-end, open-end, and custom silicon nitride thermocouple tubes, depending on the thermocouple assembly and installation method.