Amorphous Ni-Zr phase formation in self-supporting thin-film lateral-diffusion couples

The formation of an amorphous Ni-Zr alloy, by heating to cause interdiffusion in the temperature range 2500C to 3250C, was demonstrated in a self-supporting lateral-diffusion couple. Micro-area diffraction in a scanning transmission electron microscope (STEM) indicates that microcrystalline ordering in the amorphous phase must be on a scale less than 5 nm. The samples were heated in a vacuum furnace to form the amorphous phase and later heated in STEM for in situ observation of crystalline compound formation. The amorphous to crystalline transformation occurs first in the Zr-rich regions at 3700C. A crystalline phase begins to consume the Ni rich amorphous material, at 4500C; but at 3250C, the amorphous phase is stable up to 20.5 hours, even in the presence of crystalline compounds