Improved thermal conductivity of graphite though infiltration with SiC and Si3N4 inclusions

Abstract

High thermal conductivity, wear resistant graphite is desirable for a range of applications, for example as an electrode to minimize energy consumption in aluminium smelting. This paper demonstrates that by infiltrating the porosity by reactive infiltration with SiC at levels ranging from 4 to 12 vol.% or Si3N4 ranging from 7 to 19 vol.% the thermal conductivity can be raised progressively from ∼41 W/m K to ∼53 and 64 W/m K respectively. A simple analytical model predicts thermal conductivity rises with increasing reinforcement fraction only 7–9 % higher than that observed. This suggests that heat transfer between the graphite and the reinforcing particles is good making these materials good options where improved thermal conductivity and wear resistance over graphite is required.