MSFC-SPEC-3200

Abstract

The Solidification Using a Baffle in Sealed Ampoules (SUBSA) is a material science investigation that will use the Microgravity Science GloveBox (MSG) Facility. The science objectives are to test the performance of an automatically moving baffle to reduce gravitational induced convection effects, and to determine the behavior and possible advantages of liquid encapsulation in microgravity conditions.<br>Ten directional solidification experiments will be conducted in the MSG with indium antimonide (InSb) contained inside transparent tubes. The experimental apparatus consists of a heater surrounding the sample/ampoule. The ampoules will contain a graphite baffle that is driven by the expansion of the melt at a constant distance from the solid/liquid interface. The baffle may demonstrate that it reduces sensitivity to residual micro-acceleration in two systems with different segregation coefficients and achieve reproducible growth. Reproducibility will help determine the behavior and possible advantages of liquid encapsulation in microgravity conditions. The power supplied to the heater is controlled to provide the needed temperature range, wetting and/or bubble formation, and motion of the solid/liquid interface. Each experiment is expected to average 10.3 hours. Ten samples, plus two spares are planned for processing on the UF-02 mission.