HIGH-RATE DISSOLUTION OF COPPER IN CUPRIC-SULFATE ELECTROLYTES

The mass-transfer-limited dissolution of copper in acidic and binary c upric-sulfate solutions is investigated. The dissolution produces a du ll surface with a coarse microtexture. This system has an unusually la rge limiting-current plateau, where a salt film precipitates. The film is characterized with steady polarization measurements as well as AC- impedance and flow-modulation spectroscopy. A low-field, film-conducti on mechanism explains best the high-frequency region of the AC-impedan ce spectrum. The electrochemical behavior of the system is compared to other high-rate metal-dissolution systems. Shortcomings of present sa lt-film models are discussed. Copyright (C) 1996 Elsevier Science Ltd