Thermal Conductivity: IV,Apparatus for Determining Thermal Conductivity by a Comparative Method

Apparatus for determining thermal conductivity by a comparative method of steady-state heat flow through 1-in. cube samples is described. Suitable precautions insure linear heat flow and low heat losses. Measurements with melting-point lead give values in good agreement with previous data. Measurements for dense Al₂O₃, BeO, and MgO indicate a conductivity which decreases with temperature from values at 100°C. of 0.50 cal. per sec.⁻¹ per °C.⁻¹ per cm.⁻² per cm. for BeO, 0.081 for MgO, and 0.067 for Al₂O₃. Values obtained are somewhat higher than most of those previously reported.