Published online by Cambridge University Press: 25 February 2011
Differential scanning calorimetry (DSC) has been used to study the temperatures, kinetics and phase formation mechanisms in Cu/Mg multilayer thin films. When the Cu:Mg layer thickness ratio was 1:4, CuMg2 was the only phase that formed. Cu/Mg films with a layer thickness ratio of 1:1 first form CuMg2 at 215°C with an activation energy of 1.0 ± 0.04 eV and then Cu2Mg at 380°C with an activation energy of 0.73 ± 0.04 eV. The temperatures at which the two phases form decrease as the layer thicknesses decrease due to the shorter reaction times needed in thinner films. The constant scan rate DSC data from films with a layer thickness ratio of 1:1 show three exothermic peaks. The first peak is extremely sharp and results from the formation of isolated nuclei of CuMg2 at the Cu/Mg interface. The formation of CuMg2 is thus shown to be nucleation controlled. The second peak is a growth peak due to the heat released during the growth of CuMg2. The third peak corresponds to the formation and growth of Cu2Mg.