Electrodeposition metal deposition fundamentals

Fundamental studies on metal deposition and electrocrystallization processes started in the first half of the twentieth century with thework of Volmer [6.3], Erdey-Gruz and Volmer [6.4], Brandes [6.5], Gorbunova and Dankov [6.6], and Kaischew [6.7]. A first attempt at a systematic study of the phenomenological aspects of electrodeposited metal coatings was made by Fischer [6.8]. 

Since the mid-1970s there has been a considerable amount of material published on the influence of ultrasound upon the electrochemistry of metal systems. Most of this work was carried out in former Eastern block countries and concentrated on such electrochemical processes as corrosion, electrodeposition, and electrochemical dissolution. Recently there has been an upsurge in the interest shown in sonoelectrochemical processes using both non-metal and metal systems worldwide. There have been a considerable number of publications in the employment of ultrasound in areas as diverse as semiconductor production to sono-electrochemical machining and metal finishing. A review by R. Walker [27] into the use of ultrasound in metal deposition systems, provides an introduction into the fundamental effects of ultrasound in plating and metal finishing. 

Popov KI, Maksimovic MD, Ocokoljic BM, Lazarevic BJ (1980) Fundamental aspects of pulsating current metal electrodeposition I the effect of the pulsating current on the surface roughness and the porosity of metal deposits. Surf Technol 11 99-I09... 

Popov KI, Maksimovic MD, Stevanovic RM, Rrstajic NV (1984) Fundamental aspect of pulsating current metal electrodeposition. VIII the effect pulse to pause ratio on microthrowing power of metal deposits. Surf Technol 22 155-158... 

Popov and Nikolic in Chapter 1 discuss the fundamental aspects of disperse metals electrodeposition. The shapes of polarization curves in relation to the deposition process parameters are analyzed. Disperse metal deposits are formed with a nonuniform current density... 

Ettel V. A. (1984), Fundamentals, practice and control in electrodeposition - an overview , in Warren I. H. (Ed.), Application ofpolarization measurements in the control of metal deposition. Amsterdam Elsevier. 

There are four types of fundamental subjects involved in the process represented by Eq. (1.1) (1) metal-solution interface as the locus of the deposition process, (2) kinetics and mechanism of the deposition process, (3) nucleation and growth processes of the metal lattice (M a[tice), and (4) structure and properties of the deposits. The material in this book is arranged according to these four fundamental issues. We start by considering the basic components of an electrochemical cell for deposition in the first three chapters. Chapter 2 treats water and ionic solutions Chapter 3, metal and metal surfaces and Chapter 4, the metal-solution interface. In Chapter 5 we discuss the potential difference across an interface. Chapter 6 contains presentation of the kinetics and mechanisms of electrodeposition. Nucleation and growth of thin films and formation of the bulk phase are treated in Chapter 7. Electroless deposition and deposition by displacement are the subject of Chapters 8 and 9, respectively. Chapter 10 contains discussion on the effects of additives in the deposition and nucleation and growth processes. Simultaneous deposition of two or more metals, alloy deposition, is discussed in Chapter 11. The manner in which... 

Underpotential deposition (UPD) is the electrochemical adsorption and (partial) reduction of a submonolayer or monolayer of cations on a foreign metal substrate at potentials more positive than the reversible potential of the deposited metal [141]. The UPD phenomenon is used in many fundamental and applied studies because it offers a means of controlling coverages during electrodeposition in a very concise manner. Until recently, most of the information obtained about the structure of the overlayers deposited on single crystal surfaces has come from indirect means such as current-voltage analysis or by analysis of the deposited films after transfer to a UHV chamber [141]. 

In ionic liquids the situation seems to be totally different. It was surprising to us that the electrodeposition of metals and semiconductors in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide delivers nanocrystalline deposits with grain sizes varying from 10 to 200 nm for the different materials, like Si, Al, Cu, Ag and In, investigated to date. It was quite surprising in the case of Al deposition that temperature did not play a tremendous role. Between 25 and 125 °C we always got nanocrystalline Al with similar grain sizes. Similar results were obtained if the deposition was performed in tri-hexyl- tetradecylphos-phonium bis (trifluoromethylsulfonyl) amide. Maybe liquids with saturated nonaromatic cations deliver preferentially nanomaterials this is an aspect which, in our opinion, deserves further fundamental studies. 

Chapter 3, by Rolando Guidelli, deals with another aspect of major fundamental interest, the process of electrosorption at electrodes, a topic central to electrochemical surface science Electrosorption Valency and Partial Charge Transfer. Thermodynamic examination of electrochemical adsorption of anions and atomic species, e.g. as in underpotential deposition of H and metal adatoms at noble metals, enables details of the state of polarity of electrosorbed species at metal interfaces to be deduced. The bases and results of studies in this field are treated in depth in this chapter and important relations to surface -potential changes at metals, studied in the gas-phase under high-vacuum conditions, will be recognized. Results obtained in this field of research have significant relevance to behavior of species involved in electrocatalysis, e.g. in fuel-cells, as treated in chapter 4, and in electrodeposition of metals. 

It should be mentioned here that the composition of the electrolyte solution used in these in situ STM studies of the electrochemical deposition of noble metals (platinum, palladium, rhodium and ruthenium) are quite different from those used in the real electroplating industry [56-58]. Although some experimental conditions (temperature, concentration) may be difficult for the in situ STM measurements, electrodeposition in a practical electrolyte bath should provide more information both in application and in fundamental fields. 

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