Thermal conductivities of molten iron, cobalt, and nickel by laser flash method

Abstract

New attempts were made for the measurement of thermal diffusivity of molten iron, cobalt, and nickel at temperatures close to 1900 K by a laser flash method. A simple but useful sample cell system was developed to keep the molten metal shape uniform for a given thickness. It is also necessary to consider the effect of not only the radiative heat loss but also the conductive heat loss at the interface between the molten metal sample and the sample cell material under the present experimental conditions. The conductive heat loss was found, through computational simulation, to be negligibly small for the present laser flash measurements. Thermal conductivity values of molten iron, cobalt, and nickel were calculated by combining the present thermal diffusivity data with specific heat and density, and the resulting values are given in the following equations (unit: W m⁻¹ K⁻¹)

$$\begin{gathered} \lambda _{Fe} = 2.15 \times 10^{ - 2} (T - 1818) + 33.3 1818 \leqslant T \leqslant 1868 (unit: K) \hfill \\ \lambda _{Co} = 2.79 \times 10^{ - 2} (T - 1768) + 30.4 1768 \leqslant T \leqslant 1838 (unit: K) \hfill \\ \lambda _{Ni} = 2.30 \times 10^{ - 2} (T - 1728) + 53.0 1728 \leqslant T \leqslant 1908 (unit: K) \hfill \\ \end{gathered} $$