Melting and solidification of Pb nanoparticles embedded in an Al matrix as studied by temperature-modulated differential scanning calorimetry

A newly developed temperature-modulated differential scanning calorimetry has been used to study the melting and solidification processes of Pb nanoparticles embedded in an Al matrix under continuous heating and cooling conditions at rates of 1-5 K min^-1Endothermic peaks have been observed in the total, the reversing and the non-reversing heat flows during the melting process, indicating that the process is controlled by both thermodynamics and kinetics. As the underlying heating rate increases, the enthalpy change in the reversing heat flow increases whereas that in the non-reversing heat flow decreases, while that in the total heat flow remains constant. On the other hand, during solidification, exothermic peaks are observed only in the non-reversing and total heat flow curves and the enthalpy changes remain essentia1ly constant when the underlying cooling rates increase from 1 to 5 K min^-1No exothermic peaks were observed in the reversing heat flow curve. This indicates that the solidification process is controlled essentially by kinetics.