The grain boundary groove shapes for Zn solid solution in equilibrium with Sn-Zn eutectic liquid were observed with a radial heat flow apparatus. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient, the solid-liquid and the grain boundary energy for the Zn solid solution in equilibrium with Sn-Zn eutectic liquid were determined to be (2.32 +/- 0.13)x10(-8) Km, (120.87 +/- 13.29)x10(-3) J.m(-2) and (194.76 +/- 23.37)x10(-3) J.m(-2), respectively. The termal conductivity of the eutectic Sn- 9 wt% Zn solid solution, kappa(S), was obtained as 74.74 W/Km by using a radial heat flow apparatus. The thermal conductivity ratio of the eutectic liquid to the eutectic solid, R = kappa(L)/kappa(S) was found to be 0.58 with a Bridgman-type directional growth apparatus. Thus, the value of the thermal conductivity of eutectic Sn-9 wt% Zn liquid solution, kappa(L), was obtained as 43.82 W/Km.