Partial and integral enthalpies of mixing of liquid ternary In-Sn-Zn alloys were determined at 500 degrees C along seven sections over a large composition range. Additionally, binary alloys of the constituent system In-Sn were investigated at the same temperature. The measurements were carried out using a Calvet-type microcalorimeter and a drop calorimetric technique. The binary data were evaluated by means of a standard Redlich-Kister polynomial fit whereas ternary data were fitted on the basis of an extended Redlich-Kister-Muggianu model for substitutional solutions. (C) 2010 Elsevier B.V. All rights reserved.