Convective and interfacial instabilities during solidification of succinonitrile containing ethanolEven though slow convective flow is difficult to detect in solidifying metals, it can readily be observed in transparent materials by observing the motion of small neutrally buoyant particles. Succinonitrile, which solidifies with an unfaceted solid/liquid interface and has well characterized physical properties, is considered an excellent material for such studies. For studies of solute-induced convection, ethanol is a useful addition to succinonitrile since it has a lower density and a somewhat similar molecular structure. Samples of high purity and ethanol-doped succinonitrile are unidirectionally solidified in a vertical temperature gradient. Latex mimcrospheres 2 microns in diameter are suspended in the liquid to reveal the convective flow. Convective and morphological stability is observed as a function of solute concentration and growth velocity. These measurements are compared with theoretical calculations that predict the transition from stability to instability as a function of solidification conditions. The predicted transitions occur at low concentrations and solidification velocities; for this reason, extreme care must be taken in order to eliminate the effects of impurities or thermally induced convection.
Document ID
19830062081
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Schaefer, R. J. (National Bureau of Standards Washington, DC, United States)
Coriell, S. R. (National Bureau of Standards Washington, DC, United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1982
Subject Category
Chemistry And Materials (General)
Meeting Information
Meeting: Materials processing in the reduced gravity environment of space; Annual Meeting