INCOTHERM® alloy TD was specifically developed for thermocouple sheathing where high-temperature corrosion resistance and strength are required without the use of elements that may cause thermocouple degradation over time.

Alloy TD is a Ni-22% Cr alloy with the addition of 1.4% Si, 3.0% Mo and rare earth elements. Elements such as manganese and aluminum, which can diffuse through the thermocouple insulator and contaminate the thermo-element wires leading to emf drift over time, are controlled at very low levels thus giving excellent long term performance. In addition, the composition is similar to the thermo-element wires, which further reduces the potential for the diffusion of elements between the alloys. The alloy has outstanding static and cyclic oxidation resistance at temperatures up to 1250°C (2282°F) and possibly beyond.

INCOTHERM alloy TD is highly resistant to oxide spalling and can therefore be considered for applications where contamination needs to be controlled at low levels, such as in glass making and electronic component processing.