Measurement of Thermal Conductivity of Electrical Conductors at High Temperatures

摘要

A new method for measuring the thermal conductivity of electrically conducting materials has been investigated that is particularly well suited for use at high temperatures. The sample has the shape of a narrow bridge between two larger masses of the same substance. The thermal conductivity is derived from the change in resistance which occurs when the narrow bridge is heated by passage of an electric current through it. The small size of the heated region makes it possible to neglect radiation at very high temperatures. It is not necessary to control the exact shape of the bridge, since geometric effects cancel out in the equations used to interpret the heating phenomena. Experimental measurements of the Lorentz ratio and thermal conductivity are reported for single‐crystal molybdenum and tungsten at temperatures up to 1700°K. The application of this method to brittle semiconductor materials is also discussed.