Electron microscopy of microstructural transformation in electrodeposited Ni-rich, Ag–Ni film

Abstract

Ag–Ni films were electrodeposited over a Cu substrate. Structural characterization revealed a fibrous microstructure with an amorphous structure for the as-deposited film. Isothermal annealing at 400°C of the film inside transmission electron microscope led to amorphous-to-crystalline transition along with the evolution of nano-sized particles in the microstructure. The crystalline phase was Ni–Ag solid solution. The relative volume fraction of the nano-sized particles increased gradually with time. There was however no detectable decomposition of solid solution phase till about 4h of annealing. Beyond 4h phase separation initiated and pure Ag and Ni phases formed in the film. This study provides a methodology by which microstructural engineering of as-electrodeposited amorphous Ag–Ni films can be conducted to isolate a particular microstructure in order to tap specific potentially usable functionalities.