RATE OF COMPOSITION CHANGES OF ORGANIC SOLID SOLUTION CRYSTALS IN SWEATING OPERATIONS

Abstract

When crystalline particles of binary solid solution mixtures of the m-chloronitrobenzene-m-fluoronitrobenzene system were placed in an atmosphere at elevated temperatures close to their equilibrium liquidus point (sweating), they gradually changed their compositions to approach the equilibrium solidus composition and also changed shape from rigid plates to porous ones. These changes continued even after 360 h, which is significantly different from the behavior observed for simple eutectic systems reported in a previous study. Quantitative analysis of the rates of composition changes were made on the basis of the diffusion mechanism of the recrystallization process during sweating.