Characteristics of reversible and irreversible electrode potentials are defined with respect to the ionic patterns characteristic of the two states. Limits of ionic exchange are seen as significant in achievement of polarization by a metal surface. The theory of electrode potentials is considered at some length with pertinent, mathematical derivations. Significance and characteristics of the double layer on a metal immersed in an electrolyte are reviewed with emphasis on ionic activity.
Theoretical and practical aspects of irreversible potentials are considered with respect to several metals and environments. Differences between the considerations affecting potentials of simple irreversible electrodes and complex electrodes are detailed in several liquid and gaseous environments. The effect of stress in lowering electrode potentials is covered, as are results of experiments in environments with oxidizers, chlorides and the effects of temperature, velocity of solution and time.
Potentials of active cathodes and anodes are discussed. Theoretical influence of films, current densities and direction and experiments with a copper-zinc couple are detailed. Uses of polarization diagrams are considered and the significance of anodic and cathodic control of a corroding system explained.
The author examines results of experiments with several complex alloys. The influence of the several components of the alloy is weighed and numerous cases involving different areas of cathode and anode and the difficulties involved in making experimental determinations of true potentials examined. Potentials of complex anodes of the film-pore type are determined by an experiment which includes a means of continuously cleaning the specimen of protective films. The nature and characteristics of films is covered as is the effect of varying thicknesses of film.
The effect of differences in lattice structure are investigated. Diagrams of potentials taken under varying conditions are given. 62 figures, 12 tables.
