Measurement of thermophysical properties of molten silicon using an upgraded electrostatic levitator

摘要

Accurate measurements of thermophysical properties of molten silicon have been attempted using an upgraded electrostatic levitator. In order to reduce the temperature gradient in the levitated sample four laser beams of equal intensity with tetrahedral heating arrangement were used. A new image processing technique was adopted to get reliable sample volume (or density) measurements. In order to increase the accuracy of surface tension and viscosity measurements sample mass was continuously monitored throughout the experiment and the effect of mass loss was accounted for in the final analysis. Based on these new improvements, the results for the density, the specific heat over hemispherical total emissivity, the surface tension and the viscosity of molten silicon can be expressed by ρ(T) = 2.583 - 1.851 x 10~(-4) (T - T_m) - 1.984 x 10~(-7)(T - T_m)~2 g/cm~3 (1370 K< T< 1830 K), C_P/ε_T = 149.433 - 0.03735 x (T - T_m) + 8.0 x 10~(-5)(T - T_m)~2 - 1.1838 x 10~(-7)(T - T_m)~3 + 1.6342 x 10~(-9)T - T_m)~4 J/molK (1370 K