Thermal Conductivity of Molten Alkali Nitrates

Abstract

Measurements of the thermal conductivities of the molten alkali nitrates are reported. A law of corresponding states is found for the conductivities, but an entirely satisfactory theoretical basis of the law is not yet available. At atmospheric pressure the conductivities increase with temperature, a behavior seen in associated liquids such as water. Moreover, the same temperature trend is observed for solid-state thermal conductivities near the melting point. This indicates that the temperature trend observed for the conductivities of the melts is not peculiar to the liquid state but is perhaps due to the nitrate ion or to the long-range Coulombic interactions. Use of the hot-wire transient method for studying thermal conductivities of molten salts is criticized.