Surface tension of molten silicon measured by the electromagnetic levitation method under microgravity

The surface tension of molten silicon was measured using the electromagnetic levitation method under microgravity. The atmosphere was Ar-3 pet H-2 purified by Pt asbestos and magnesium perchlorate. The partial oxygen pressure is estimated to be less than 1.1 x 10(-14) Pa. The spherical droplet shape was controlled by changing the current ratio between a quadrupole coil and a dipole coil. The surface tension of molten silicon can be expressed by the equation gamma = 735 - 0.074 (T - 1687) where gamma is the surface tension (in mN/m) and T is the temperature (in K). The value was measured over a wide range of temperatures, from 230 K below the melting point (1687 K) to 1890 K. The scatter of the measured surface-tension values is much less than that measured by conventional methods.