Thermocouples operate based on the Seebeck effect, a phenomenon where two different metal wires joined at one end produce an electromotive force (EMF) when exposed to a temperature difference. This voltage correlates to the temperature difference between the hot and cold junctions, allowing for accurate temperature measurement.

Type C thermocouples are specifically designed for extreme high-temperature environments, offering precision and stability where other thermocouples degrade. Their unique tungsten-rhenium composition allows them to function reliably at temperatures up to 4,200°F (2315°C), making them essential for industries requiring precise thermal monitoring in challenging conditions.

Type C thermocouples utilize a specialized Tungsten-Rhenium (W-Re) alloy, enhancing their durability and performance:

• W-5%Re (positive leg) – Improves thermal stability and structural strength.
• W-26%Re (negative leg) – Enhances ductility and prevents brittleness at extreme temperatures.

Key Advantages:

• Unmatched heat resistance – Maintains accuracy beyond 2000°C, surpassing the limits of most thermocouples.
• High melting point – Tungsten’s melting point of 6,192°F (3422°C) makes it ideal for sustained high-temperature exposure.
• Superior electrical response – Produces a strong EMF output for precise readings.

Type C thermocouples perform optimally in controlled environments, as tungsten-rhenium alloys are susceptible to oxidation at high temperatures.

Best suited for:

• Vacuum chambers
• Inert gas atmospheres (Argon, Helium)
• Hydrogen-rich environments

Not recommended for:

• Oxygen-rich environments above 3000°F (1650°C), as oxidation can cause rapid degradation.

Industries such as aerospace, defense, semiconductor processing, and metal heat treatment depend on Type C thermocouples for their high-temperature stability.

The operating temperature of a Type C thermocouple varies based on wire thickness:

Larger wire diameters withstand higher temperatures and last longer, while smaller diameters provide faster response times but degrade more quickly.

To prevent oxidation and extend lifespan, Type C thermocouples require protective sheaths:

• Ceramic Sheaths (Alumina – Al₂O₃): Excellent thermal stability and high-temperature resistance.
• Metal Sheaths (Molybdenum, Tantalum, Inconel): Ideal for vacuum and inert gas conditions.
• Molybdenum & Tantalum: Best for aerospace and vacuum furnace applications.
• Inconel: Provides oxidation resistance but with lower maximum temperature limits.

For accurate readings, Type C thermocouples require high-quality insulation and reliable extension wires:

Insulation Options:

• Alumina & Hafnia – Withstands extreme heat, non-conductive.
• Magnesium Oxide (MgO) – Excellent thermal conductivity, commonly used in industrial applications.

Extension Wires:

• Fiberglass Braid – Rated up to 900°F (480°C).
• PFA/FEP Plastic Coating – Insulated for stability up to 400°F (200°C).

Type C thermocouples excel in ultra-high-temperature environments where other thermocouples fail. Their precision and durability make them essential for various industries:

Cleveland Electric Laboratories (CEL) is a trusted leader in high-temperature sensor technology, providing precision, durability, and reliability across critical industries.

• ISO 9001 Certified – Commitment to consistent, high-quality manufacturing.
• AS9100D Certified – Meeting the rigorous demands of aerospace and defense.
• ISO/IEC 17025 Calibration – Ensuring accurate, traceable temperature readings.