Calorimetric determination of NiAl3-growth kinetics in sputter-deposited Ni/Al diffusion couples

Ni/Al multilayer films with 1:3 molar ratio and periodicities in the range 640-2000 nm were prepared by sputter deposition, and investigated by differential scanning calorimetry and X-ray diffraction. X-ray diffraction showed that only NiAl3 formed inthe reaction of these films. The calorimetry measurements were analyzed using one-dimensional diffusion-controlled growth kinetics. The activation energies so obtained were in the range 1.64-1.76 eV, and the pre-exponential factors were (5-50)x10(-4) m(2) s(-1). These kinetic growth parameters were extracted from the calorimetry data using a variety of analysis methods applied to constant heating-rate calorimetry data. Good agreement was found among the results of the various methods. The present paper, in addition to providing the kinetic parameters for the growth of nickel trialuminide in these Ni/Al films, demonstrates the general utility of multilayer films and calorimetric methods in the determination of the growth kinetics of intermetallic phases in diffusion couples. (C) 1997 Elsevier Science S.A.