Anodic dissolution of metals under mass transport control
Abstract
This paper is focussed on anodic dissolution processes controlled by mass transport. After the recall of the results obtained for a classic redox system, four examples are discussed :
1.
(i) iron dissolution in sulphuric acid for which a liquid layer of high visosity is formed at the interface;
2.
(ii) copper dissolution in hydrochloric acid and
3.
(iii) in phosphate acid, where in both solutions a solid salt layer is existing at the electrode surface; and
4.
(iv) nickel dissolution in sulphate acid media, where a very high Schmidt number is involved in the mass transport.
On the basis of the analysis of steady-state results and electrohydrodynamic impedance, it is evidenced that each system needs a particular description.