Thermophysical Properties of POCO Graphite.

Abstract : The thermal conductivity, specific heat, and electrical resistivity of two samples of POCO AXM 5Q graphite obtained from NBS were measured. These results, combined with previous results for thermal expansion and high temperature specific heat were used to compute thermal diffusivity values from 400 to 2400K The computed diffusivity values agreed well with measured values. The electrical resistivity of the two samples differed significantly from each other and also varied along the length of the rods. Differences in thermal conductivity values between the two samples were directly related to difference in resistivity. In general the results of other researchers could be brought into agreement with the present results, based on differences in resistivity (and density). Consequently it was possible to generate curves of electrical resistivity, thermal conductivity, specific heat and thermal diffusivity of POCO AXM 5Q graphite from 400 to 2400K. There is an electronic contribution to the thermal conductivity. This contribution is less than a few percent at 400K but increases to at least 15% at 2400K. (Author)