Precise measurement of physical properties of high melting point melts using microgravity environment

利用目前世界上使用时间最长、质量最高的微重力环境--悬浮液滴法，对高温熔体，特别是液态硅的表面张力和密度进行了测量，主要研究结果如下：（1）建立了微重力环境下高温熔体表面张力和密度的测量方法。(2)分析了由表面张力引起的熔体表面振荡模式。(3)在这项工作中获得的表面张力值比以前的作品更可靠。(4)由于无容器工艺，在过冷条件下测量了表面张力和密度。(5)在本实验条件下，液态硅的表面张力不受大气中氧分压的影响。(6)液态硅的熔点表面张力为734 mN/m，温度系数为0.069mN/mK。(7)得到了计算表面张力时修正方程的适用范围。(8)悬浮滴法测量密度时，必须控制液滴的位置。

Surface tension and density of high temperature melts, especially liquid silicon were measured with the levitated drop method using microgravity environment which is the longest term, 10 seconds, and the highest quality on the earth.The results can be summarized as follows ;(1) A measurement method for surface tension and density of high temperature melts under microgravity environment.(2) Surface oscillation mode of melt caused by surface tension was analyzed.(3) Surface tension values obtained in this work were more reliable than those in previous works.(4) Surface tension and density were measured under supercooled condition because of containerless process.(5) Surface tension of liquid silicon was not affected by an oxygen partial pressure in an atmosphere in the present experimental condition.(6) Surface tension and its temperature coefficient of liquid silicon were 734 mN/m at the melting point and 0.069 mN/mK, respectively.(7) An applicable range of correction equation was obtained for a calculation of surface tension.(8) Positioning of liquid drop must be controlled to measure the density by the levitated drop method.