Interfacial energies of p-dichlorobenzene–succinonitrile alloy

The commercial purity para-dichlorobenzene (p-DCB) and succinonitrile (SCN) were purified using a columnar distillation system. Thin-walled specimen cells (60–80 μm thick) were fabricated and filled with the purified materials under the vacuum. A thin liquid layer was melted and the specimen was annealed in a constant temperature gradient for an enough time to observe the equilibrated grain boundary groove shapes. The thermal conductivities of solid and liquid phases for purified p-DCB and p-DCB–2.7 mole% SCN alloy were determined with the radial heat flow and Bridgman-type growth apparatuses. From the observed grain boundary groove shapes, the Gibbs–Thomson coefficient and solid–liquid interfacial energy of solid p-DCB in equilibrium with p-DCB–SCN monotectic liquid have been determined to be (6.1 ± 0.6) × 10−8 K m and (29.2 ± 4.4) × 10−3 J m−2. The grain boundary energy of p-DCB phase has been determined to be (54.6 ± 9.3) × 10−3 J m−2 from the observed grain boundary grooves.