Abstract: The size of nano Fe powders was determined to be 25 nm in diameter by SEM. The isobaric molar heat capacity Cp of the nano Fe was measured with the high precision adiabatic low-temperature calorimeter in the temperature range from 84 K to 350 K. The relationship of Cp with temperature T was established as: Cp=36.831+14.772 x−5.4968x2−0.7099x3−1.3188x4, where x=(T−234)/156. The thermodynamic functions of the nano Fe, relative to the standard temperature of 298.15 K, were derived based on the heat capacity data through thermodynamic relationship. The measured Cp values were compared with those of coarse crystal powders and 87 nm Fe powders cited from literature and the difference between the Cp curves was analyzed

Key words: Nano Fe, Low-temperature heat capacity, Heat capacity enhance, Thermodynamic functions, Adiabatic calorimetry