Periodic Phenomena during Anodic Dissolution of Copper at High Current Densities

Abstract

Uniform and sustained anode potential oscillations (amplitude, 10-20V) have been observed in galvanostatic dissolution of copper in chlorate electrolyte. The oscillations occur in the current density range of 0.3-150 A/cm 2. Frequency increases with current density in this range from 10 -3 to 103 Hz. Increases in electrolyte temperature, acidity, and flow rate were found to result in a decrease of oscillation frequency. Large amplitude oscillations were also observed in a narrower current density range and with less cycle uniformity, in a variety of mixed electrolytes containing small concentrations of halides. The rise and fall of potential reflects an alternate growth and destruction of an adherent cuprous oxide surface layer. A model for the oscillations is proposed based on resistive switching transitions within the anode surface film.The anodic dissolution of copper in sodium chlorate electrolyte gives rise to a remarkable phenomenon. On applying a constant current to the cell, the anode potential fails to reach a steady level; rather, the potential undergoes a periodic rise and fall of about 10V, as shown by the sample oscillograph recording (Fig. I). The individual cycles are impressively uniform in period and amplitude. Oscillations are found with galvanostatically controlled current densities in the range of 0.3 to over 150 A/era 2. Above approximately 180 A/cm 2, random fluctuations accompanied by gassing and sparking were observed. Frequency increases with 9 Electrochemical Society Active Member.

Temporal Instabilities in Corrosion Processes

“…The oscillatory electrooxidation of Cu anode in HCl or NaCl solutions has been studied since 1920s of the twentieth century [50][51][52][53] and some attempts to explain the mechanisms of these oscillations were made by Cooper et al [54]. Here we shall focus on more recent studies of these oscillations in various acidic chloride solutions, performed by Lee et al [55,56], using rotating disk copper electrode.…”

Localized passivity breakdown of iron in chlorate- and perchlorate-containing sulphuric acid solutions: A study based on current oscillations and a point defect model

“…The presence of Cl − was identified in the solution by means of a potentiometric titration with a standardized solution of silver nitrate. Chloride production by reduction of ClO 3 − was assumed to occur during electromashining of mild steel [39] as well as during Cu dissolution where Cu + is the reducing species [40].…”

“…Perchlorates and especially chlorates are used in important technological processes such as electromachining and electropolishing of mild steel [38][39][40][41]. The effect of chlorates and perchlorates on the iron passivity was previously considered to occur via pitting corrosion caused by these ions themselves [41,42].…”

Self‐Organized Formation of Layered Nanostructures by Oscillatory Electrodeposition

“…Oxidation of H 2 [19][20][21][22][23] Cu [53][54][55][56][57][58][59][60][61][62] Zn [88][89][90][91][92][93] Oxidation of HCHO [24,25] Fe [63][64][65][66][67][68][69][70][71] Sn [94][95][96][97][98] Oxidation of HCOOH [26][27][28][29][30][31][32] Co [72][73][74][75] Au [99,100] Oxidation of CO [33,34] Ni …”

“…H 2 O 2 reduction on a Pt electrode is a very interesting reaction in that various oscillations appear only by making slight changes in the experimental conditions [59][60][61][62]. Among the various oscillations, the oscillation caused by competition between the H 2 O 2 reduction and the formation of upd-H has been most extensively studied.…”