Thermal Conductivity of the Na–Pb System Liquid Alloys

The thermal conductivity λ of liquid sodium–lead alloys (10, 21, 31, 41, 50, and 63 at % of Pb) was measured by the laser flash method in the temperature range from the liquidus line to 1070 K with an uncertainty of 4–6%. The temperature and concentration dependences of λ are constructed. It was found that for most of the studied alloys, thermal conductivity increases monotonically with temperature and has rather low values compared to pure Na and Pb melts: from 3.7 to 12.0 W/(m K). A gently sloping minimum was found on the concentration dependence of λ in the lead concentration range X_Pb ≈ 20–50 at %. Correlations are noted between the obtained results on thermal conductivity and other thermophysical properties, which indirectly confirm the existing literature ideas about the formation of ionic complexes in the liquid Na–Pb system.