Electrodeposition from Deep Eutectic Solvents

Abstract

Deep eutectic solvents constitute a class of compounds sharing many similarities with properly named ionic liquids. The accepted deinition of ionic liquid is a luid liquid for T< °C) consisting of ions, while DES are eutectic mixtures of Lewis or "rønsted acids and bases. Their most atractive properties are the wide potential windows and the chemical properties largely diferent from aqueous solutions. In the last few decades, the possibility to electrodeposit decorative and functional coatings employing deep eutectic solvents as electrolytes has been widely investigated. " large number of the deposition procedures described in literature, however, cannot ind application in the industrial practice due to competition with existing processes, cost or diicult scalability. From one side, there is the real potential to replace existing plating protocols and to ind niche applications for high added-value productions to the other one, this paves the path towards the electrodeposition of metals and alloys thermodynamically impossible to be obtained via usual aqueous solution processes. The main aim of this chapter is therefore the critical discussion of the applicability of deep eutectic solvents to the electrodeposition of metals and alloys, with a particular atention to the industrial and applicative point of view.Keywords: electrodeposition, deep eutectic solvents, metals, alloys . IntroductionThe electrodeposition of metals for industrial surface inishing is nowadays a well-established industrial practice. Many processes are available to obtain a wide variety of coatings on most of © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. the substrates used in manufacturing. There are however some important limitations, as not all the metal/substrate combinations are possible in the current state of the art. This is connected to the nature of the electrolytes used for the vast majority of the plating processes, which are water based. Water is the most obvious choice to formulate a plating electrolyte, and in the majority of the cases, it is also the most convenient from the point of view of the results obtained. This solvent however presents some limitations: narrow potential window, reactivity towards speciic metals, high hydrogen evolution in speciic conditions, etc. If metal plating is limited to aqueous solutions, many possibilities are therefore precluded." possible way to extend the range of coating/substrate combinations is the use of non-aqueous solvents, characterized by ext...

Electrodeposition of Magnetic SmCo Films from Deep Eutectic Solvents and Choline Chloride-Ethylene Glycol Mixtures

“…SmCo codeposition was firstly studied from a solution containing 0.04 M SmCl 3 . 6H 2 O and 0.04 M CoCl 2 .…”

“…Silver pseudo-reference electrode was employed for all the experiments, potential values were referred to Ag wire. Prior each experiment, all electrodes were cleaned with a 10 wt% HNO 3 ] (0.12 M) was added to evaluate its effect on deposition process and film properties. All reagents employed were of analytical grade.…”

“…[7][8][9] In literature, works on this alloy from both waterbased [10][11][12][13][14][15][16] and non-aqueous solution are reported. 17 In the former case, fundamental is the employment of glycine as complexing agent as shown by Wei et al [13][14][15] However, in-plane coercivities in the order of H c|| = 100 Oe were observed with the formation of SmO, Sm(OH) 3 and Co(OH) 2 .…”

“…Ionic liquids are in fact characterized by wider electrochemical windows limiting the onset of secondary processes suppressing the metal reduction one. [1][2][3] One practical example is the electrodeposition of rare earth metals and their alloys (e.g. SmCo).…”

The importance of using hydrogen evolution inhibitor during the Zn and Zn-Mn electrodeposition from ethaline

“…), semiconductors and photovoltaic alloys (In-Ga, CuGaSe 2 ), and alloys for electrocatalytic application (Ni-Co-Sn, Co-Pt). 2 Our group focuses research on Zn-Mn alloy electroplating as a corrosion resistant coating on steel, from aqueous solutions, 3 but we also reported the electrodeposition process of Zn-Mn alloy from deep eutectic mixture of choline chloride and urea, with trade name reline. 4 The motivation for using DES in Zn-Mn electroplating is the fact that water baths suffer from instability, low current efficiency or poor deposit morphology due to the hydrogen evolution reaction.…”