Structural phase transformations in Al/Pt bilayer thin films during the solid-state reaction

A sequence of phases forming during the solid-phase reaction in Al/Pt bilayer thin films has been investigated by in situ electron diffraction. It is shown that the amorphous PtAl$_2$ phase forms first during the solid-phase reaction initiated by heating. Upon further heating, PtAl$_{2}$, Pt$_{2}$Al$_{3}$, and PtAl, Pt$_{3}$Al crystalline phases sequentially form, which is qualitatively consistent with an effective formation heat model. The content of phases forming during the reaction has been quantitatively analyzed and the structural phase transformations have been examined.