Low temperature heat capacity and thermal stability of nanocrystalline nickel

The heat capacity (Cp) of nanocrystalline nickel (nc-Ni, 40 nm crystallite size) has been measured over the temperature range of 78–370 K with a high-resolution automated adiabatic calorimeter. The measured results are compared with the Cp values of the corresponding coarse-grained crystal, and an enhancement of heat capacity of the nanocrystalline nickel was observed to be 2–4% in the temperature range between 100 and 370 K. The thermal stability of the nanocrystalline nickel sample was determined by a differential scanning calorimeter and a thermogravimetric system. The melting point of nc-Ni is the same as that of the corresponding coarse-grained crystalline nickel and the sample is stable at temperature lower than 500 K.