Modelling of copper etching in aerated chloride solutions

M. Georgiadou, R. Alkire

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of dissolved oxygen on the rate of chemical etching of copper by acidic cuprous chloride solution was investigated numerically for the case of a rotating disc electrode (RDE). Copper dissolution in aerated acidic cupric chloride solutions of composition 3.5 M CuCl2 + 0.5 M HCl + 0.5 M KCl and 3.5 M CuCl2 + 0.5 M HCl was investigated with consideration of the instantaneous homogeneous reaction 4 CuCl2-3 + 4H+ + O2 ⇌ 4 CuCl-3 + 2 H2O which takes place within the mass transport boundary layer. It was assumed that CuCl2-3 and O2 react instantaneously, resulting in the formation of a reaction plane which separated the mass transport boundary layer into two regions: a region adjacent to the electrode where oxygen was depleted, and a region adjacent to the bulk where CuCl2-3 was absent. A one-dimensional mathematical model was developed to predict the position of the reaction plane. The model accounted for diffusion, migration and fluid flow generated by an RDE and included nine species and five heterogeneous electrochemical reactions. The homogeneous redox reaction served to regenerate the chemical etchant solution and thus enhance the etch rate. With increasing oxygen concentration and rotation rate the reaction plane was found to move closer toward the electrode and thus the etch rate of copper increased. Addition of KCl increased the Cl- content in solution so as to shift the reaction plane toward the bulk.

Original languageEnglish (US)
Pages (from-to)127-134
Number of pages8
JournalJournal of Applied Electrochemistry
Volume28
Issue number2
DOIs
StatePublished - Feb 1998

Keywords

  • Copper etching
  • Cuprous chloride solution
  • One-dimensional model
  • Rotating disc electrode

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry
  • Materials Chemistry

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