Thermophysical Properties of Molten Germanium Measured by a High-Temperature Electrostatic Levitator1

Thermophysical properties of molten germanium have been measured using the high-temperature electrostatic levitator at the Jet Propulsion Laboratory. Measured properties include the density, the thermal expansivity, the hemi- spherical total emissivity, the constant-pressure specific heat capacity, the surface tension, and the electrical resistivity. The measured density can be expressed by \liq=5.67_103&0.542 (T&Tm) kg}m&3 from 1150 to 1400 K with Tm=1211.3 K, the volume expansion coefficient by :=0.9656_10&4 K&1, and the hemispherical total emissivity at the melting temperature by =T, liq(Tm)=0.17. Assuming constant =T, liq(T)=0.17 in the liquid range that has been investigated, the constant-pressure specific heat was evaluated as a func- tion of temperature. The surface tension over the same temperature range can be expressed by _(T)=583&0.08(T&Tm) mN}m&1 and the temperature dependence of the electrical resistivity, when rliq(Tm)=60 +0 } cm is used as a reference point, can be expressed by re, liq(T)=60+1.18_10&2(T&1211.3) +0 } cm. The thermal conductivity, which was determined from the resistivity data using the Wiedemann Franz Lorenz law, is given by }liq(T)=49.43+ 2.90_10&2(T&Tm) W}m&1 } K&1.