Determination of thermal conductivities at high temperatures

Abstract

The usual electrical methods of determining thermal conductivities either cannot be used at high temperatures or their use is restricted to substances like carbon or graphite which satisfy certain special requirements. It is shown that the observed temperature distribution along a metal filament electrically heated in a vacuum can be used for the determination of the thermal conductivity at high temperatures. The temperature distribution near the centre of a short filament, which is known to be parabolic, or the distribution in regions slightly removed from the centre of a long filament, which is known to be logarithmic, are particularly suitable for this purpose. Measurements are reported on the thermal conductivity of platinum in the temperature region 1300 to 1800° K made in this manner.