Some effects of surface states of corroding metals on the kinetic characteristics of the dissolution processes

✍ Scribed by G. Bech-Nielsen; M. Mogensen; J. C. Reeve

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: German
• Weight: 767 KB
• Volume: 31
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.19800310503

✦ Synopsis

Abstract

Depending on etching, iron in chloride or sulphate solutions and in some degree copper in perchlorate solution can be made to follow one or the other of two clearly different dissolution behaviours. This is attributed to the establishment of two alternative states of the metal surface. For both metals the transitions (at constant potential) between the two states can be followed by means of cd‐time curves, and one of these transitions can be described in terms of the Avrami equation. The rates of the transitions are dependant on potential and on the composition of the electrolyte solution, but because of the great number of details influencing these phenomena a complete interpretation is not yet available. However, sources of some experimental errors are discussed in detail, and for iron electrodes it is shown that other fundamental phenomena than the relaxation of pit shape must be assumed as the basis of the transitions.