Kinetics aspects of initial stage thin γ-Al2O3 film formation on single crystalline β-NiAl (110)

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The growth kinetics and mechanisms of thermally-grown thin γ-Al2O3 film at 650 °C in air on single-crystalline β-NiAl (110) was characterized via transmission electron microscopy, X-ray diffractometry, and thermo-gravimetric analyses. The oxidation kinetics as a function of thickness was gradually changing from an inverse-logarithmic to parabolic behavior across the “intermediate thickness regime” as the oxide thickness increases. To define the boundaries of the three thickness regimes, the high field approximation (x1) and Debye-Hückel length (LD) were determined using the existing theoretical kinetics models combined with experimentally measured data. All the relevant constants for each rate law at the three thickness regimes were also experimentally determined to quantitatively describe the initial stage growth kinetics.