Abstract The temperature dependence of the thermodynamic properties of V, in Pt-V alloy, was investigated in this study. A Pt strip was equilibrated with V2O3 powder, under controlled oxygen partial pressure and temperature. The mole fraction of V in the sample was measured with an electron probe micro-analyzer, and the activity coefficient of V was determined as a function of temperature and composition. With increasing temperature, the activity coefficient of V ( γ V ) increased. The activity coefficient at infinite dilution ( γ V o ) increased and the interaction parameter ( e V V ) decreased with rising temperature. The excess Gibbs energy value for the fcc phase Pt-V alloy was strongly negative.