Pulse Electrodeposition of Copper in the Presence of a Corrosion Reaction

Abstract

This study has examined the pulse electrodeposition of copper from a deep eutectic solvent.Pulse plating parameters were selected using the methodologies originally developed for aqueous solutions, including constraints arising from double layer charging and mass transport effects. Although copper could be deposited under nearly all conditions, in many instances only partial plating was observed and current efficiencies were low. This effect was greatest at low duty cycles and/or when the off-time was long. This phenomenon was attributed to a corrosion (comproportionation) reaction occurring in the off-time. A simple model based on the corrosion reaction being under cathodic mass transport control was developed. While this could explain the main effects, it predicted a corrosion rate that was typically higher than observed. A variety of other models were then explored, the most plausible one indicating that the corrosion rate in the off-time is being controlled by a slow chemical dissolution step. This explained the main observations and predicts that, only for long pulse periods when steady-state conditions are approached, is the corrosion rate under cathodic mass transport control. Finally, it was found that benzotriazole could be employed to substantially reduce the corrosion rate and allow higher current efficiencies to be obtained.

Review—Influence of Corrosion Reactions on the Pulse Electrodeposition of Metals and Alloys

“…In deriving these expressions, it is assumed that the number of electrons involved in the deposition and dissolution steps are the same. This is normally the case but there are some exceptions, and in previous papers 20,21 a variant of Eq. 2 was used to reflect this.…”

“…However, some early 6,18 and more recent [19][20][21] studies have shown that it is possible to have corrosion processes occurring during the offtime which can significantly influence deposit properties and current efficiency. This has been observed for the pulse plating of certain metals (e.g.…”

“…Au and Cu) and can arise due to conventional oxygeninduced corrosion, 6,19 or alternatively, by comproportionation reactions. [18][19][20][21] Similarly, during the pulse electro-deposition of binary and ternary alloys from aqueous and non-aqueous solutions, displacement (corrosion) reactions have been observed in the off-time that can significantly alter the alloy composition and microstructure. [22][23][24] This effect has been more extensively studied, and has been reported in both aqueous [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] and non-aqueous [41][42][43] systems.…”

Dynamic Galvanic Corrosion of Working Lithium Metal Anode Under Practical Conditions

“…Traditionally, chemical corrosion is the most established type of corrosion reactions on Li metal anode, which involves the direct redox reactions occurring between Li metal and nonaqueous electrolyte, giving rise to a solid electrolyte interphase (SEI) growth on the Li surface. [ 6a,7 ] This process is spontaneous and ubiquitous during both calendar aging and dynamic electrochemical cycling of Li metal anode. SEI is expected to serve as a passivation layer to kinetically terminate the proliferation of chemical corrosion.…”

A systematic study of pulse and pulse reverse plating on acid copper bath for decorative and functional applications

“…PC mainly used to influence the mechanisms of electrocrystallisation, which in turn control the mechanical and physical properties of the deposited metal 16 , 17 . Since the nucleation rate is proportional to the current density, the use of pulsed single or bipolar currents, which can reach densities significantly higher than their stationary counterparts, can produce deposits with reduced porosity and, a finer grain size 18 , 19 .…”