Thermophysical properties measurement of molten silicon by high-temperature electrostatic levitator: density, volume expansion, specific heat capacity, emissivity, surface tension and viscosity

Abstract

Thermophysical properties of molten silicon measured by the high-temperature electrostatic levitator at JPL are presented. The properties include the density, the volume expansion, the constant pressure specific heat capacity, the hemispherical total emissivity, the surface tension and the viscosity. Over the temperature range investigated (1350–1850 K), the measured liquid density showed a quadratic nature expressed by ρ( T)=2.58−1.59×10 −4 ( T− T m)−1.15×10 −7 ( T− T m) 2 g/cm 3 with T m=1687 K. The volume expansion with respect to the melting point could be expressed by V( T)/ V m=1+6.18×10 −5 ( T− T m)+4.72×10 −8 ( T− T m) 2. The hemispherical total emissivity of molten silicon at the melting temperature was 0.18, and the constant pressure specific heat was determined over a 500 K around the melting point. The measured surface tension and the viscosity could be expressed respectively by σ( T)=765−0.016 ( T− T m) mN/m, and η( T)=0.75−1.22×10 −3 ( T− T m) mPa s.