Platinel

the general name for alloys of noble metals for electrodes of highly sensitive thermocouples (~39 microvolts per °C).

The composition of the alloy for the positive electrode is 55 percent Pd, 31 percent Pt, and 14 percent Au, and for the negative electrode, 65 percent Au and 35 percent Pd. Thermocouples made of Platinel alloys can measure temperatures up to 1300°C over the course of hundreds or thousands of hours in oxidizing or inert media, as well as in dry hydrogen. The calibration characteristics of such thermocouples at temperatures of 600°-1300°C virtually coincide with the calibration characteristics of Chromel-Alumel thermocouples; therefore, thermocouples of Platinel alloys are usually used with compensation leads made of Chromel and Alumel, with maintenance of the cold junction temperature at 600°-800°C. This makes possible the production of very short thermocouple electrodes.

Thermocouples made of Platinel alloys are mainly used for measuring and regulating the temperature of gas streams in gas-turbine engines.