THE THERMAL CONDUCTIVITY OF PLATINUM BETWEEN 300 AND 1 000 °K

Abstract

The thermal conductivity of high-purity platinum was measured between 300 and 1 000 °K. The results obtained agree very well with the previously reported work of Bode and of Martin and Sidles, but at higher temperatures are in definite disagreement with the results of Powell and Tye. The observed variation of the thermal conductivity with temperature implies that at high temperatures the (electronic) Lorenz number of platinum is an increasing function of temperature, exceeding in magnitude the Sommerfeld value. Such behavior of the Lorenz number can be understood qualitatively if one assumes a low Fermi energy for platinum, an assumption usually made to account for the behavior of its high-temperature electrical resistivity.