A Review of Nanostructural Aspects of Metal Electrodeposition

In this review we address the electrochemical growth of metals and alloys with nanometric structures controlling the functional properties of electrodeposited coatings and freestanding electroforms. Electrodeposition is starting to be regarded as a viable process for nanofabrication and - even though electrocrystallisation has received considerable attention from both the theoretical and experimental viewpoints - it is now worth focussing systematically on the role of processing and electrochemical engineering factors, in the tailoring of nanosized structural features. This information is currently scattered in the literature and a specific review would fill an information gap. This paper offers: (i) an overview of the tools currently avaliable for the description and in-situ and ex-situ assessment of the nanostructure of electrodeposited metals; (ii) a systematic discussion of the relationships among their nanostructure and mechanical and chemical properties; (iii) a rationalisation of the mechanisms of formation of the different types of nanoelectrodeposits; (iv) a critical presentation - ordered by chemical composition - of specific systems. An updated and comprehensive literature coverage is provided, based on over 300 papers.