THERMAL CONDUCTIVITY OF METALS AT HIGH TEMPERATURES BY JAIN AND KRISHNAN METHOD .2. COBALT

The improved Jain and Krishnan method is used to measure the thermal conductivity of cobalt in the temperature range 1200-1500°K. The thermal conductivity decreases up to the Curie point (similar 1390°K) and, after showing a minimum at this temperature, starts increasing slowly. The values of electrical resistivity and total and spectral emittances are also reported in the same temperature range. Below the Curie temperature electrical resistivity and thermal conductivity are strongly dependent on temperature. The lattice conductivity is found to be negative even after using the modified form of Lorenz ratio suggested by Backlund. Further theoretical work is necessary to understand the mechanism of conduction in cobalt.