The grain boundary groove shapes for equilibrated solid aminomethylpropanediol solution, BCC (AMPD-42.8 mol% NPG-3 mol% DC) in equilibrium with the liquid (AMPD-7 mol% NPG-3 mol% DC) have been directly observed by using a horizontal linear temperature gradient apparatus. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient (Gamma), solid-liquid interfacial energy (sigma(SL)) of solid AMPD solution have been determined to be (5.20 +/- 0.52) x 10(-8) Km and (8.89 +/- 1.33) x 10(-3) J m(-2), respectively. The grain boundary energy of solid AMPD solution has been determined to be (17.12 +/- 2.73) x 10(-3) J m(-2) from the observed grain boundary groove shapes. The ratio of thermal conductivity of equilibrated liquid to thermal conductivity of solid AMPD solution has also been determined to be 0.35. (C) 2013 Elsevier B.V. All rights reserved.