High temperature electrical resistivity of rigid thermal insulation fabricated from carbon fiber felt

Rigid thermal insulation material fabricated from carbon fiber felt has been used for high temperature applications such as heating in an artificial graphite furnace, e.g., silicon semiconductor manufacture. In this study, the high temperature electrical resistivity of rigid thermal insulation materials, one of its important properties, was measured by a prototype device developed by the author, and factors influencing it are investigated. The resistivity of rigid thermal insulation decreased by 60% during heating to 2000 °G For temperatures above 2200 °C, different behaviors were observed between argon and nitrogen atmospheres. In the case of an Ar atmosphere, the high temperature resistivity decreased steeply as the temperature increased from 2200 to 2500 °C, but this was not observed when the atmosphere was changed to nitrogen. On the other hand, such a difference in the high temperature resistivity behavior above 2200°C between Ar and N2 atmospheres was barely noticeable for isotropic graphite and glass-like carbon.