Abstract
Electrodeposition and electropolishing of nanograined nickel has been observed using an in situ electrochemical wet cell developed for transmission electron microscopy. The cell employs two thin film nickel electrodes in a 0.1 M aqueous NiCl2 electrolyte, which were biased at ±1 V. Anisotropic electrodeposition was observed in which growth of the nickel film across the substrate occurred much more rapidly than growth perpendicular to the substrate. The anisotropic behavior results from relatively equiaxed nanograins nucleating at the growth front with little subsequent coarsening. Grains were observed to nucleate ahead of the growth front, suggesting a new mechanism for electrochemically driven growth across a substrate which depends on ionic surface adsorption ahead of the growth front. During electropolishing the dissolution of nickel tended to occur more isotropically. The film thinned relatively uniformly until certain regions displayed Rayleigh instabilities. At this point the film broke up and some regions coarsened rapidly and/or were subject to electromigration.
Original language | English (US) |
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Pages (from-to) | 192-198 |
Number of pages | 7 |
Journal | Acta Materialia |
Volume | 60 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2012 |
Keywords
- Electrochemical characterization
- In situ transmission electron microscopy
- Nickel
- Thin film
ASJC Scopus subject areas
- Ceramics and Composites
- Metals and Alloys
- Polymers and Plastics
- Electronic, Optical and Magnetic Materials