The Measurement of Thermal Conductivity of Refractory Materials

Thermal conductivity of titania, mullite, and zircon have been measured in the range from 200°C to l400°C by the ellipsoid envelope method.Measurement of conductivity of AI2O3, BeO and MgO has been extended to l800°C by employing inductive heating.All these materials showed an increase in thermal conductivity above about 1500°C which is believed due to the effect of radiant transmission by the translucent specimens.A new derivation of the heat flow equations for ellipsoidal specimens and calculations of the effect of porosity are presented.The thermal conductivity of AI2O3, BeO, and MgO over the entire temperature range from room temperature to l800°C is analysed and the effects of radiation and translucency considered.