Modes of inhibiting electrode processes (corrosion included) and their experimental discrimination. I. Definition, nomenclature and classification of modes of inhibition in electrochemical electrode reactions

Abstract

Abstract As to the modes of inhibiting electrode processes, it belongs to the present tasks of the Working Party “Inhibitors” of the European Federation Corrosion first to elaborate valid formulations in definition, nomenclature and classification and second to present a review on methodology for investigating inhibition experimentally. The author is offering contributions to these themes for discussion. Regarding the international character of the European Federation, these contributions were written in English. In the following part I, inhibition of electrode reactions is defined and classified in Interface inhibition Electrolyte‐layer inhibition Membrane‐inhibition Passivation. Different modes of covering the interface are leading to interface inhibition: Desactivating, indifferent or reactive coverage. Peculiarities in the interface inhibition of electrolytical metal deposition and dissolution are discussed. Electrolyte‐layer inhibition is subdivided in a mechanical and an electrochemical species. Envisaging the origin of the inhibiting substances, primary and secondary inhibitors are distinguished. This subdivision is applied to interface and electrolyte‐layer inhibition. Even by their nature, membrane inhibition and passivation are secondary. Finally, the inhibition of two or more electrode reactions running down simultaneously and their further classification are treated. It is called special attention to peculiarities of the most important representative of this group, the corrosion inhibition (including vapour phase inhibition). The review on methodology will be given in part II to be published later.