The kinetics of dissolution of ordered phase with Pt₂Mo structure has been studied in two nickel chromium alloys – one without molybdenum and another with molybdenum - using differential scanning calorimetry. The activation energy for dissolution, determined using three nonisothermal approaches was found to be ~418 kJ /mole for both the alloys. This value agreed very well with the activation energy for coarsening of g" precipitates in Ni-Cr-Mo matrix and is close to activation energy for mobility of chromium and molybdenum in complex nickel alloy matrix.