When it comes to measuring extreme temperatures in industrial settings, thermocouples are indispensable tools, and among the most reliable are the S type, R type, and B type thermocouples. These are part of the noble metal thermocouple family, known for their exceptional stability and accuracy in high-temperature environments—often exceeding 1,500°C.
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S type thermocouple: Composed of 90% platinum and 10% rhodium (positive leg) and pure platinum (negative leg), it’s ideal for applications like furnace calibration and semiconductor manufacturing, where precision up to 1,600°C is critical.
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R type thermocouple: Similar to the S type but with a higher rhodium content (13% in the positive leg), it offers slightly better stability at elevated temperatures, making it a top choice for aerospace and metallurgical processes.
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B type thermocouple: Designed for even hotter conditions (up to 1,800°C), this variant uses 70% platinum-30% rhodium in both legs, resisting oxidation and corrosion in harsh environments like glass production.
For temperatures beyond 2,000°C, tungsten rhenium thermocouples take the lead. Their high melting points (tungsten: 3,422°C; rhenium: 3,186°C) make them perfect for vacuum furnaces and nuclear research.
