The high-temperature Lorenz number of tungsten; an analysis of recent results on the thermal and electrical conductivity over the temperature range 300 to 1300 K

A recently described method has been used to measure thermal and electric conductivities of an arc-cast tungsten specimen in the range 300 to 1300 K. The Lorenz number was calculated from the measured results. In contrast to reported data at high temperatures the present results yield the Sommerfeld value within the experimental uncertainty of some percent and and agree with theoretical expectations. (author)