Calorimetric observations of amorphous and crystalline Ni-Zr alloy formation by solid-state reaction

Differential scanning calorimetry and x-ray diffraction are utilized in a study of solid-state vitrification of multilayered composites of Ni and Zr. In order to understand better and optimize the amorphizing reaction, we have examined the kinetics of competing reactions: the formation and growth of crystalline intermetallic compounds. The value of the activation energy, Ec, of the initial crystallization of the growing amorphous phase is determined to be Ec=2.0±0.1 eV, establishing an upper limit on the thermal stability of the amorphous-diffusion couple