Observation of artifact-free amorphous structure in Cu-Zr-based alloy using transmission electron microscopy

The effect of the sample preparation method on the observation of amorphous structure in glass forming Cu-Zr, Cu-Zr-Ti and Cu-Zr-Ti-Ni alloys (Cu-Zr-based alloys) using transmission electron microscopy (TEM) has been investigated. The result shows that the selection of a proper sample preparation method is crucial in observing artifact-free amorphous microstructure, since Cu-Zr-based alloy is readily oxidized in air atmosphere. Electro-chemical thinning or electro-chemical thinning followed by ion milling causes oxide (Cu2O and CuO) contamination on the surface of the sample. Only low-energy ion milling with liquid nitrogen cooling can result in the observation of a fully amorphous structure. The exposure time of the thin foil sample in air before TEM examination should be minimized to observe the microstructure without contamination.