Computer-aided Knudsen cell mass spectrometry is used for the thermodynamic investigations on ternary Au-Co-Pd melts over the entire range of composition. The "digital intensity-ratio" (DIR)-method has been applied for the determination of the thermodynamic excess quantities, and the ternary thermodynamically adapted power (TAP) series concept is used for algebraic representation of the thermodynamic mixing behavior. The corresponding TAP parameters as well as the values of the molar excess Gibbs energies GE, of the molar heats of mixing HE, of the molar excess entropies S-E, and of the thermodynamic activities at 1800 K are presented. (C) 2009 Elsevier B.V. All rights reserved.