Thermophysical properties of highly doped Si₅₀Ge₅₀ melt were measured contactlessly in the electromagnetic levitation facility ISS-EML on board the International Space Station. The sample could be melted, overheated by about 375 K, and cooled down in 350 mbar Argon atmosphere. A large undercooling of about 240 K was observed and a quasi-homogeneous nucleation on the droplet surface occurred. During the cooling phase, high-resolution videos were taken from the side and the top. The density and thermal expansion were evaluated with digital image processing; the viscosity and the surface tension were measured by means of the oscillating drop technique. Inductive measurements of the electrical resistivity were conducted by a dedicated electronics. All data were taken as a function of temperature T from the overheated melt down to the undercooled range. We found a nonlinear thermal expansion, suggesting a many body effect in the liquid beyond the regular pair interaction, an enhanced damping of surface oscillations likely related to an internal turbulent flow, and an increment of the electrical resistivity with decreased T in the undercooled range regarding a demixing of the components.

高掺杂Si ₅₀ Ge _50的热物理性质在国际空间站上的电磁悬浮设施ISS-EML中非接触式测量熔体。样品可能会熔化，过热约375 K，并在350 mbar的氩气气氛中冷却。观察到约240 K的过冷度过大，液滴表面出现准均相成核。在冷却阶段，从侧面和顶部拍摄高分辨率视频。通过数字图像处理评估密度和热膨胀；粘度和表面张力通过振荡滴技术测量。电阻率的电感式测量是通过专用电子设备进行的。所有数据均取为温度T的函数从过热熔体到过冷范围。我们发现了非线性的热膨胀，这表明除了规则的对相互作用之外，液体中还有许多体效应，可能是与内部湍流有关的增强的表面振动阻尼，以及在过冷范围内电阻率随T的降低而增加组件的混合。