Direct observation on solidification of binary organic eutectic alloys

Abstract

With a view to elucidate the chemistry of transparent binary organic systems of phenanthrene with acenaphthene, o-toluic acid and acetanilide, their phase diagram was determined by the thaw-melt method. The data on linear velocity of crystallization (v) of pure components and eutectics, determined by the rate of movement of the interface in a capillary at different undercoolings (ΔT), obey the Hillig-Turnbull equation. The values of heat of fusion, determined by the DTA method, were used to compute enthalpy of mixing and excess thermodynamic functions. These thermodynamic parameters are needed to throw light on the structure, stability and ordering in the eutectic melts. Microstructural studies showed that freshly precipitated eutectics have different characteristics microstructures from their parent components.