Isotech Thermocouple Standards Platinum/Palladium
- Superior stability to Platinum / Platinum Rhodium
- Very Low Uncertainties
- Temperature Range 0 to 1500°C
The Platinum‑Palladium (Pt‑Pd) thermocouple is one of the most accurate and stable high‑temperature thermocouples available. Made from ultra‑pure noble metals, it provides exceptional long‑term stability and reproducibility, making it a preferred reference sensor for laboratories operating under ITS‑90 and other international metrology standards.
Designed for high temperatures and long‑term stability
Pt‑Pd thermocouples excel in temperature ranges where conventional thermocouples (such as Types R, S or B) begin to show drift or instability. The combination of platinum and palladium produces a highly linear and repeatable EMF response, even at temperatures above 1000 °C.
Both metals offer excellent oxidation resistance and extremely high melting points, ensuring stable performance during extended high‑temperature operation.
Ideal for fixed‑point realization and comparison calibration
The Platinum‑Palladium thermocouple is commonly used with:
- > Aluminium fixed‑point cells (660.323 °C)
- > Silver fixed‑point cells (961.78 °C)
- > Gold fixed‑point cells (1064.18 °C)
- > Copper fixed‑point cells (1084.62 °C)
Its low drift and excellent reproducibility make it ideal for monitoring melt and freeze plateaus, as well as for comparison calibrations in furnaces such as the Isotech Oberon, Medusa 511, or other high‑temperature systems.
Construction and materials
A Pt‑Pd thermocouple typically consists of:
- > positive leg: high‑purity platinum
- > negative leg: high‑purity palladium
- > insulation: alumina (Al₂O₃) for high‑temperature stability
- > sheath: quartz, alumina or metal depending on the application
This construction minimizes contamination, diffusion and drift — essential for metrological accuracy.
Applications
The Platinum‑Palladium thermocouple is used in:
- > primary and secondary metrology laboratories
- > ITS‑90 fixed‑point realization
- > high‑temperature comparison calibration
- > materials research at elevated temperatures
- > monitoring of blackbody cells
It is one of the few thermocouples capable of delivering long‑term, reproducible measurements above 1000 °C.
The Platinum‑Palladium thermocouple offers an exceptional combination of stability, reproducibility and high‑temperature capability. For laboratories requiring absolute accuracy at temperatures exceeding 1100 °C, it is an indispensable tool in high‑temperature metrology.
