| 研究実績の概要 |
Hollow silicon millispheres have been fabricated using a hollow coaxial jet for the first time. Silicon was melted in a graphite crucible at 1823 K, then ejected from the annulus of a coaxial nozzle as argon gas was injected from an inner nozzle whose inner and outer diameters are 0.4 mm and 1 mm respectively. Sphere diameters were 1 - 2 mm with spherical outer surfaces, and the frequency of formation was approximately 145 Hz. The wall thicknesses varied gradually between antipodes. The interior surfaces were somewhat non-spherical, with horn-like structures where the wall was thicker, most likely owing to silicon expansion as solidification finishes. This is the first report of such a “horn expansion structure” observed on a concave substrate.
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