We have utilized differential scanning calorimetry to monitor the solid-state reaction of crystalline metals to form an amorphous alloy in multilayered thin-film diffusion couples of elemental Ni and Zr. The heat of formation of amorphous ${\mathrm{Ni}}_{68}$${\mathrm{Zr}}_{32}$ alloy from the elemental metals is measured directly and found to be 35 ± 5 kJ/mole. The kinetics of these reactions has been examined. The activation energy for interdiffusion in the amorphous phase is determined to be $E=1.05\mathrm{}\pm 0.05$ eV.

• Received 25 August 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.2295