Measurements of Thermophysical Properties of Molten Silicon by a High-Temperature Electrostatic Levitator

Several thermophysical properties of molten silicon measured by the high-temperature electrostatic levitator at JPL are presented. They are density, constant-pressure specific heat capacity, hemispherical total emissivity, and surface tension. Over the temperature range investigated (1350 less than T(sub m) less than 1825 K), the measured liquid density (in g/cc) can be expressed by a quadratic function, pi(P) = p(sub m) - 1.69 x 10(exp -4)(T - T(sub m)) - 1.75 x 10(exp -7)((T - T(sub m))(exp 2) with T(sub m) and p(sub m) being 1687 K and 2.56 g/cc, respectively. The hemispherical total emissivity of molten silicon at the melting temperature was determined to be 0.18, and the constant-pressure specific heat was evaluated as a function of temperature. The surface tension (in 10(exp -3) N/m) of molten silicon over a similar temperature range can be expressed by sigma(T) = 875 - 0.22( T - T(sub m)).