Mechanism of eutectic crystallization. II

Relative undercooling, linear velocity of crystallization and microstructure of eutectics have been investigated for (i) naphthalene-m-nitroanaline, (ii) m-dinitrobenzene-phenanthrene, (iii) m-dinitrobenzene-acetanilide, and (iv) 2,4 dinitrophenol-acetanilide systems. The linear velocity of crystallization I for pure components and eutectics is found to depend on Δ according to the equation I = K(ΔT)n, where K and n are constants. For the eutectics, apparently lamellar structure in system (ii) and rod type structure in systems (iii) and (iv) are obtained. For system (ii), the interlamellar spacing λ and I are related by the equation λ = cI-12. The experimental data have also been examined in the light of recent theory of lamellar growth due to Jackson and Hunt.