Dendrite Tip Shape in Pivalic Acid-Ethanol and Succinonitrile-Salol Systems

Abstract

In the present work, dendrite tip shapes are fitted by parabolic function, and the difference of dendrite tip shapes between the pivalic acid(PVA)-ethanol(Eth) and succinonitrile(SCN)-salol systems which are characterized by anisotropic and isotropic solid-liquid interfacial property, respectively, is quantitatively treated using shape parameters. PVA-Eth system shows slightly higher Z/R value than SCN-salol system, their Z/R values lying in the range 2-4. (Z is the distance from the tip beyond which the parabolic fit starts to deviate from the profile, and R the tip radius.) λp is the distance from the tip beyond which side branching starts to appear, and is different for both sides of the 2-dimensional dendrite profile. The difference of λp between both sides of the dendrite is larger for PVA-Eth system than for SCN-salol, implying that the dendrite of PVA-Eth is more nonaxisymmetric than that of SCN-salol.