Partial thermodynamic properties of Sb in liquid Ni-Sb-Sn alloys were determined by an isopiestic vapor pressure method. Vapor pressures of Sb were measured along two sections with constant x(Ni)/x(Sn) values, i.e. Ni3Sn-Sb and Ni3Sn2-Sb. Data points were obtained between approximately 52 and 88 at.% Sb in the temperature interval from 1080 to 1350 K. From these measurements, the thermodynamic activities of Sb were calculated, and the partial molar enthalpies of mixing of Sb were derived from their temperature dependence. The composition dependence of the Sb activity in the two sections was calculated for 1173 K and was compared with data for the limiting binary systems Sb-Sn and Ni-Sb. (C) 2012 Elsevier B.V. All rights reserved.