落下塔を利用してのバルク結晶材料合成

抄録

Synthesis of bulk materials in the short-duration microgravity of the AIST's 10m drop tower have been studied. The unidirectional cooling apparatus combined with rapid cooling system was developed for the short-duration microgravity experiments. Congruent melt materials were focus to the experimental target. CdTe with a few mm-sized grains were obtained from the melt in the microgravity experiment. The cooling profile explains obvious undercooling with released latent heat. When some of impurities were added into the melt, well-oriented needle like structures were grown. Well-oriented structures are useful for improving material functions. Zn4Sb3, with oriented grains obtained in the microgravity experiment had 50% higher thermoelectrical properties in the perpendicular direction of cooling direction than that in the parallel direction of cooling direction.